http://hdl.handle.net/1811/6631 Wed, 22 May 2013 06:17:18 GMT 2013-05-22T06:17:18Z http://hdl.handle.net/1811/15880 THE MICROWAVE SPECTRUM OF NORMAL PROPYL IODIDE. Sarachman, T. N. The microwave spectrum of normal propyl iodide has been studied in the spectral region from 18 GHz to 36 GHz. The observed spectrum is accounted for by the presence of two rotational isomers, the gauche and trans forms of the molecule. Because of the great mass of the iodine atom, both rotational isomers are very nearly symmetric prolate rotors. The trans form spectrum consists of the $J \rightarrow J +1, \Delta K=0 R^{a}$ transitions, of which only the $K = 1$ lines are resolved; the gauche spectrum exhibits in addition to these $R^{a}$ transitions a series of $Q^{b}$ transitions $J_{1,J-1}\rightarrow J_{2J-2}$. Results of the spectral analysis will be given, and the molecular geometry will be discussed. Author Institution: Department of Physics, State University of New York at Buffalo Wed, 01 Jan 1969 00:00:00 GMT http://hdl.handle.net/1811/15880 1969-01-01T00:00:00Z Sarachman, T. N. http://hdl.handle.net/1811/15879 MICROWAVE SPECTRUM OF METHYLCYCLOPROPYL KETONE. Lee, P. L.; Schwendeman, R. H. The microwave spectrum of methylcyclopropyl ketone has been examined in the 8-36 GHz region. A very rich spectrum has been observed in which b-type transitions have been assigned for a species with the carbonyl group cis to the cyclopropyl ring. The transitions are split into doublets by the internal rotation of the methyl group. Transitions have been assigned for species in the first three excited states of the torsional motion in which the acetyl group rotates with respect to the cyclopropane ring. The rotational constants for the ground state are $A = 7204.33 MHz, B = 2630.88 MHz$, and $C = 2301.11$ MHz. The height of the barrier to internal rotation of the methyl group is 1175 cal/mole. Author Institution: Department of Chemistry, Michigan State University Wed, 01 Jan 1969 00:00:00 GMT http://hdl.handle.net/1811/15879 1969-01-01T00:00:00Z Lee, P. L. Schwendeman, R. H. http://hdl.handle.net/1811/15878 THE MICROWAVE SPECTRUM OF GLYCOLALDEHYDE. Simons, Margaret A.; Woods, R. C. Glycolaldehyde $(CHOCH_{2}OH)$ has been found to exist in an intramolecularly hydrogen bonded ring structure with a plane of symmetry. A large number of transitions have been assigned in the frequency range 8-18GHz for the normal species and for $CHOCH_{2}OD$. The rotational constants derived from these data are $A = 18,446.28 MHz, B = 6525.92, C = 4969.23$ for the normal and $A = 17491.15, B = 6499.57, C = 4883.10$ for the deuterated form. Five sets of lines due to excited vibrational states have also been assigned. Preliminary Stark effect measurements indicate $\mu_{a} = 0.50D$ and $\mu_{b} =2.38D$ are the dipole moment components. Author Institution: Department of Chemistry, University of Wisconsin Wed, 01 Jan 1969 00:00:00 GMT http://hdl.handle.net/1811/15878 1969-01-01T00:00:00Z Simons, Margaret A. Woods, R. C. http://hdl.handle.net/1811/15877 COMMENTS ON THE MICROWAVE SPECTRA OF METHYLCHLORO-DIAZIRINE, TRIMETHYLAMINE AND ETHYLENE EPISULFOXIDE. Wollrab, James E. Ground state rotational spectra of $CH_{3}^{25}CICN_{2}$ and $CH_{3}^{37}CICN_{2}$ have been assigned, and the derived $r_{0}$ structural parameters are: $r(NN)= 1.241 \pm 0.005{\AA}, r(CCl) = 1.743 \pm 0.01{\AA}, r(CC) = 1.498 \pm 0.01{\AA}, \sphericalangle CC-C-Cl = 116.7^{\circ} \pm 1.0^{\circ}, \sphericalangle CCN_{2} = 124.5^{\circ} \pm 1.0^{\circ}$, and $\sphericalangle NCN = 50.2^{\circ} \pm 0.5^{\circ}$. The internal rotation splittings for $CH_{3}^{35}CICN_{2}$ yield a barrier to internal rotation of $1689 \pm 10$ calories mole$^{-1}$. The Cl quadrupole coupling constants (MHz) for $CH_{3}^{35}ClCN_{2}$ are $\chi_{aa} = -66.51, \chi_{bb}=32.91, \chi_{cc}=33.60$ and for $CH_{3}^{37}ClCN_{2}$ are $\chi_{aa}=- 53.07, \chi_{bb} = 26.40, \chi_{cc} = -66.51, \chi_{bb} = 32.91, \chi_{cc} = 33.60$ and for $CH_{3}^{37}ClCN_{2}$ are $\chi_{aa} -53.07, \chi_{bb} = 26.40, \chi_{cc} = 26.67$. The nitrogen quadrupole splitting were generally unresolved. The ground state rotational spectra of $(CH_{2}D) (CH_{3})_{2}N, (CH_{3})_{3}^{15}N$, and $(^{13}CH_{3}) (CH_{3})_{2}N$ have been assigned yielding the effective moments of inertia. This information has been combined with that for $(CH_{3})_{3}N$ to give the following structural parameters: $\begin{array}{l}r(CN) = 1.451 \pm 0.003 {\AA}, r(CH_{8}) = 1.109 \pm 0.008{\AA},\\ r(CH_{a}) = 1.088 \pm 0.008{\AA}, \sphericalangle CNC = 110.9^{\circ} \pm 0.6^{\circ},\\ \sphericalangle NCH_{a} = 111.7^{\circ} \pm 0.4^{\circ}, \sphericalangle NCH_{a} = 110.1^{\circ} \pm 0.5^{\circ},\\ \sphericalangle H_{a}CH_{a} = 108.1^{\circ} \pm 0.7^{\circ}, and \sphericalangle H_{a}CH_{a} = 108.6^{\circ} \pm 0.8^{\circ},\end{array}$ where $H_{2}$ lies in a symmetry plane. $A C_{3v}$ equilibrium conformation has been established and the methyl groups appear to be tilted by $1.3^{\circ}$ toward the unshared electron pair. A mild Coriolis interaction has been observed between the lowest two vibrational states of ethylene episulfoxide. LeRoy H. Scharpen is co-author of methylchlorodiazirine work. Victor W. Laurie is co-author of trimethylamine work William F. White is co-author of ethylene episulfoxide work.; Author Institution: McDonnell Douglas Corporation Wed, 01 Jan 1969 00:00:00 GMT http://hdl.handle.net/1811/15877 1969-01-01T00:00:00Z Wollrab, James E. http://hdl.handle.net/1811/15876 THE MOLECULAR ZEEMAN EFFECT IN $O_{3}, OF_{2}, CH_{3}C^{14}N, CH_{3}^{14}NC, H_{2}CF_{2}, H_{2}C = CF_{2}, cis-HFC = CHF, OCF_{2}, PF_{3}, OPF_{3}, SOF_{2}$, AND $SO_{2}F_{2}$. Pochan, J. M.; Blickensderfer, R. P.; Wang, J. H. S.; Stone, R. G.; Flygare, W. H. The magnetic properties of the above molecules will be discussed. Both the first-order (H) and second-order ($H^{2}$) Zeeman parameters (molecular g-values and magnetic susceptibility anisotropies) have been measured. The molecular quadrupole moments and other interesting molecular parameters are discussed in light of the molecular electronic structures. Author Institution: Noyes Chemical Laboratory, University of Illinois Wed, 01 Jan 1969 00:00:00 GMT http://hdl.handle.net/1811/15876 1969-01-01T00:00:00Z Pochan, J. M. Blickensderfer, R. P. Wang, J. H. S. Stone, R. G. Flygare, W. H. http://hdl.handle.net/1811/15875 MOLECULAR G-VALUES, MAGNETIC SUSCEPTIBILITIES, AND MOLECULAR QUADRUPOLE MOMENTS IN CYCLOPROPENE, FLUOROBENZENE, FURAN, THIOPHENE, TRIMETHYLENE OXIDE, TRIMETHYLENE SULFIDE, ETHYLENE OXIDE, AND ETHYLENE SULFIDE. Benson, R. C.; Tigelaar, H. L.; Sutter, D.; Huttner, W.; Flygare, W. H. The molecular Zeeman effect has been observed in the series of ring compounds listed above. Both the first order (H) and second order ($H^{2}$) Zeeman parameters are recorded and listed for the above molecules. The first-order parameters are the molecular magnetic moments or molecular g-values and the second-order parameters are the magnetic susceptibility anisotropies. Combining these experimental parameters gives the molecular quadrupole moments for these molecules. The electronic distributions are discussed as well as the magnetic properties of the rings. The sign of the electric dipole moment of cyclopropene is also obtained. Author Institution: Noyes Chemical Laboratory, University of Illinois Wed, 01 Jan 1969 00:00:00 GMT http://hdl.handle.net/1811/15875 1969-01-01T00:00:00Z Benson, R. C. Tigelaar, H. L. Sutter, D. Huttner, W. Flygare, W. H. http://hdl.handle.net/1811/15874 THE MOLECULAR ZEEMAN EFFECT AND MAGNETIC SUSCEPTIBILITY ANISOTROPIES IN ACETYLENIC MOLECULES. Shoemaker, R. L.; Flygare, W. H. High-resolution microwave spectroscopy is combined with high magnetic fields (up to 30,000 gauss over a 6 foot length) to yield resolvable first-order (H) and second order $(H^{2})$ Zeeman spectra in a large number of molecules. The magnet and phase locked microwave spectrograph ($2.0-40.0$ gHz) will be described briefly. The molecular Zeeman effect has been observed in fluoroacetylene, methylacetylene, and methyldiacetylene. The molecular g-values and magnetic susceptibility anisotropies are given which lead to the second moment of the electronic charge distribution and molecular quadrupole moments. The magnetic properties of these molecules will be discussed in light of recent work on $CH_{3}CN$ and $CH_{3}NC$. The possible additivity of group magnetic susceptibilities will also be discussed. Author Institution: Noyes Chemical Laboratory, University of Illinois Wed, 01 Jan 1969 00:00:00 GMT http://hdl.handle.net/1811/15874 1969-01-01T00:00:00Z Shoemaker, R. L. Flygare, W. H. http://hdl.handle.net/1811/15873 THE MICROWAVE SPECTRA OF 2-METHYL-1-BUTEN-3-YNE, trans-AND $cis-1,3$-PENTADIENE Hsu, S. L. The microwave spectra of 2-methyl-1-buten-3-yne, trans-1,3-pentadiene and cis-1,3-pentadiene were all assigned and the methyl group barriers to internal rotation were measured. The results for 2-methyl-1-buten-3-yne are: $A = 9359.58 \pm 0.02 MHz, B \pm 4013.52 \pm 0.01 MHz, C = 2854.80 \pm 0.01 MHz, V_{3} = 2011 \pm 70 cal/mole$. For trans-1,3-pentadiene $A = 28.5 GHz, B = 2161.6 \pm 0.2 MHz, C = 2033.2 \pm 0.2 MHz, V_{3} = 1813 \pm 60$ cal/mole. For cis-1,3-pentadiene: $A = 15.6 GHz, B = 2659.2 \pm 0.1 MHz, C = 2306.1 \pm 0.1 MHz, V_{a} = 750 \pm 50$ cal/mole. The molecular electric dipole moments were also measured in the three molecules. The methyl group barriers to internal rotation will be interpreted in light of present theories. Author Institution: Noyes Chemical Laboratory, University of Illinois Wed, 01 Jan 1969 00:00:00 GMT http://hdl.handle.net/1811/15873 1969-01-01T00:00:00Z Hsu, S. L. http://hdl.handle.net/1811/15872 SYMMETRY PROPERTIES OF THE INTERNAL COORDINATE SPACE DERIVED FROM ITS METRICAL TENSOR (G MATRIX). Dellepiane, G.; Gussoni, M.; Zerbi, Giusepp In the present paper it is shown that the G matrix provides directly: 1) the point group to which the molecule belongs (characters of the irreducible representations); 2) the separation into symmetry species of the symmetry coordinates derived, as already discussed$^{1}$ by diagonalization of the G matrix; and 3) the symmetry properties of the potential energy matrix. On the basis of this method a program has been written which, given the G matrix as input, computes the properly factorized G and V. F. F. Z matrices. The method may also be extended to chain molecules. $^{1}$ M. Gussoni, G. Zerbi, J. Mol. Spectry, 26, 485 (1968).; Author Institution: Istituto di Chimica dell Macromolecole, c/o Istituto Chimica Industriale Wed, 01 Jan 1969 00:00:00 GMT http://hdl.handle.net/1811/15872 1969-01-01T00:00:00Z Dellepiane, G. Gussoni, M. Zerbi, Giusepp http://hdl.handle.net/1811/15871 DISTRIBUTION OF EIGENVALUES AND EIGENVECTORS OF CHAIN MOLECULES CONTAINING RANDOM DEFECTS. Gussoni, M.; Dellepiane, G.; Zerhi, G. In a previous $work^{1}$ Dean's negative eigenvalue theorem has been used to compute the distribution of eigenvalues of a chain molecule containing randomly distributed mass defects. The method has been extended to conformational $defects^{2}$ and, in the present work, to force constant defects. For a better understanding of the molecular dynamics of the chain, we have also applied the Givens-House-holder's method which allows to obtain the distribution of eigenvectors corresponding to approximate eigenvalues of very large matrices. Results will be presented and discussed. $^{1}$ Tasumi, G. Zerbi J. Chem. Phys. 48, 3813 (1968). $^{1}$ L. Piseri, G. Zerbi Chem. Phys. Letters 2, 127 (1968).; Author Institution: Istituto di Chimica del Macromolecole, c/o Istituto Chimica Industriale Wed, 01 Jan 1969 00:00:00 GMT http://hdl.handle.net/1811/15871 1969-01-01T00:00:00Z Gussoni, M. Dellepiane, G. Zerhi, G. http://hdl.handle.net/1811/15870 MEASUREMENT OF ABSOLUTE INTENSITIES IN MICROWAVE ROTATIONAL SPECTROSCOPY Scharpen, Leroy H.; Curl, R. F., Jr. A method of calibrating signal strength for the Hewlett-Packard spectrometer by introducing a known modulation index has been devised. The curve of power versus grid voltage for the frequency stabilized backward wave oscillator microwave source is determined. Then a small, known 33.3 kHz square wave voltage is applied to the grid. From the magnitude of this voltage and the power versus grid voltage curve, the modulation index may be calculated and the propertionality constant (overall gain constant) relating signal strength to modulation index determined. The absolute intensities of the lines of several compounds have been measured and compared with theory. Both the maximum peak signal ($\eta$) method and the product of unsaturated absorption coefficient and unsaturated line width ($\gamma_{0} \Delta$) method have been used and will be compared. Application of absolute intensity measurement to quantitative analysis and to determination of thermodynamic quantities will be discussed. This work was supported in part by National Science Foundation Grant GP 6305X.; Author Institution: Hewlett-Packard Company Palo Alto; Chemistry Department, Rice University Wed, 01 Jan 1969 00:00:00 GMT http://hdl.handle.net/1811/15870 1969-01-01T00:00:00Z Scharpen, Leroy H. Curl, R. F., Jr. http://hdl.handle.net/1811/15869 THE INVERTOR: AN EXACTLY SOLUBLE MODEL FOR THE ROTATION-INVERSION PROBLEM OF ETHYLENEIMINE-TYPE MOLECULES. Attanasio, A.; Bauder, A.; Günthard, Hs. H. Several molecules, mostly amines, are known to show large amplitude internal motions of the inversion type. The prominent feature is normally the tunneling of a hydrogen atom through a potential barrier. The simplified model for such a molecule consists of a rigid frame and a hydrogen atom or a group of atoms which are bound to the frame to move on a circular path between the two equilibrium positions. The classical Hamiltonian of the over-all rotation and inversion is set up and converted to the correct quantum-mechanical Hamiltonian for this model. It is shown that the matrix elements of the Hamiltonian can rigorously be calculated in a basis composed of the symmetric rotor wave functions and the trigonometric functions. The form of the potential function was chosen as to reproduce the characteristics of a double minimum potential but to facilitate the calculation of the matrix elements. Author Institution: Laboratory for Physical Chemistry, Swiss Federal Institute of Technology Wed, 01 Jan 1969 00:00:00 GMT http://hdl.handle.net/1811/15869 1969-01-01T00:00:00Z Attanasio, A. Bauder, A. Günthard, Hs. H. http://hdl.handle.net/1811/15868 MICROWAVE SPECTRA OF TORSIONALLY EXCITED STATES OF NITROETHYLENE. Nosherger, P.; Bauder, A.; Gonthard, Hs. H. Nitroethylene shows a torsional motion of the nitro group with a frequency of $99.5 cm^{-1}$ in the far infrared. In the microwave spectrum, the ground state and five excited torsional states could be measured for the lowest pure rotational transitions. It was already shown that the equilibrium structure is planar. An attempt to explain the variation of the rotational constants and the inertia defect in the different torsional states with the existing theories of Oka and Morino or Lauric and Herschbach failed. The discrepancies mainly arise from the neglect of anharmonic terms in the torsional motion. However, the application of the recently developed theory of hindered internal rotation with $C_{2v}$-type internal rotors gave an excellent fit of the measured spectra.; Author Institution: Laboratory for Physical Chemistry, Swiss Federal Institute of Technology Wed, 01 Jan 1969 00:00:00 GMT http://hdl.handle.net/1811/15868 1969-01-01T00:00:00Z Nosherger, P. Bauder, A. Gonthard, Hs. H. http://hdl.handle.net/1811/15867 THE MICROWAVE SPECTRUM OF MORPHOLINE. Sloan, J. J.; Kewley, R. The microwave spectrum of morpholine has been observed within the 8-40 GHz region. The ground vibrational state rotational constants and quadrupole coupling constants for the chair equatorial conformer are (in MHz) for undeuterated morpholine $A = 4924.88, B = 4625.15, C = 2684.25, \chi_{aa} = 2.22, \chi_{bb} = 2.51, \chi_{cc} = -4.73$ and for N-deutero morpholine $A = 4925.39, B = 4399.67, C = 2607.09, \chi_{aa} = 1.92, chi_{bb} = 2.59, \chi_{c} = -4.51$. The dipole moment of this conformer has been determined to be 1.71 D. Author Institution: Department of Chemistry, Massachusetts Institute of Technology; Department of Chemistry, Queen's University Wed, 01 Jan 1969 00:00:00 GMT http://hdl.handle.net/1811/15867 1969-01-01T00:00:00Z Sloan, J. J. Kewley, R. http://hdl.handle.net/1811/15866 MICROWAVE SPECTROSCOPY FROM $8.0-40.0$ GHz OF THE OH- ION IN THE KCI AND NaCl LATTICES AT $1.2^{\circ} K$. Scott, R. S.; Flygare, W. H. Microwave resonant absorption has been observed in $OH^{-}$-doped KCl and NaCl crystals. Several lines were observed from $8-40$ GHz by using relatively standard spectroscopic techniques. The zero-field spectra obtained here indicate that the $OH^{-}$ ion experiences a strong $C_{4v}$ potential in addition to the expected octahedral crystal field. The $C_{4v}$ potential probably arises from a shift of the $OH^{-}$ center of mass from the lattice site. Author Institution: Materials Research Laboratory and Noyes Chemical Laboratory, University of Illinois Wed, 01 Jan 1969 00:00:00 GMT http://hdl.handle.net/1811/15866 1969-01-01T00:00:00Z Scott, R. S. Flygare, W. H. http://hdl.handle.net/1811/15865 HIGH RESOLUTION INFRARED SPECTRA OF SMALL CRYSTALS OF BARIUM AND THALLOUS AZIDE. Iqbal, Zafar The vibrational spectra of large sized crystals of sodium, potassium and cesium azides have been studied by $Bryant.^{1}$ In the present study, high resolution spectra in the region $4000-200 cm^{-1}$ of single crystals of anhydrous barium azide (dimensions $5.00\times 1.00\times 0.10 mm$) and thallous azide (dimensions $2.50\times 0.70\times 0.014 mm$) have been recorded using a dual Perkin Elmer $6\times$ microsampling attachment with a Perkin Elmer 621 grating spectrophotometer. A large number of bands were observed for barium azide. The selection rules for the internal and lattice vibrations and their combinations were calculated by the ``unit cell'' $method^{2}$ in terms of the crystal structure proposed by $Choi^{3}$ from the neutron diffraction data. Due to low space group symmetry and the presence of two distinct azide ions, multiple splitting of the fundamental modes were observed. Four closely spaced strong bands in the symmetric stretching region (approx. $1360 cm^{-1}$) have been assigned to the infra-red forbidden $\nu_{1}$ frequency, which is allowed by breakdown of selection rules due to asymmetry in one of the azide ions. The spectrum shows good agreement with the neutron diffraction results and the crystal structure described by the space group $C^{2}_{2h}-P2_{1}/m$. The greater sensitivity of barium azide to shock and heat compared with the alkali metal azides can be correlated with the presence of asymmetry in the lattice. The spectrum of thallous azide is similar to that of potassium and cesium azide and supports the accepted space group $D^{18}_{4h}-I4/mcm$. An interesting feature is the fact that the asymmetric stretching frequency $(\nu_{3})$ is at a lower energy compared with the alkali metal azides. This would suggest that the azide ions are more labile in thallous azide. $^{1}$ J. Bryant, J. Chem. Phys. 45, 689 (1966) and references therein. $^{2}$ S. Bhagavantam and T. Venkatarayudu, ``Theory of Groups and Its Applications to Physical Problems'' (Andhra University Press, Waltair, India, 1951) p. 127-140. $^{3}$ Chang S. Choi, to be published (1969).; Author Institution: Solid State Branch, Explosive Laboratory, Feltman Research Laboratories Wed, 01 Jan 1969 00:00:00 GMT http://hdl.handle.net/1811/15865 1969-01-01T00:00:00Z Iqbal, Zafar http://hdl.handle.net/1811/15864 THE INFRARED SPECTRUM OF PRUSSIAN BLUE AND OTHER METAL-IRON CYANIDE COMPOUNDS. Wilde, R. E.; Ghosh, S. N. The infrared spectra of Prussian blue and compounds of the type $M_{2}[Fe(CN)_{6}$ where $M = Cu, Zn$, Cd have been obtained in the region $33-4000 cm^{-1}$. In addition, Prussian blue has been spectroscopically studied in the temperature range $300^{\circ}K-4^{\circ}K$. Spectra obtained at $300^{\circ} K$ and $77^{\circ}K$ are different in the region of the Fe-C stretching motion. The infrared spectra will be correlated with the x-ray, magnetic susceptibility, and Mossbauer studies in an effort to clarify the structures of the metal-iron cyanide compounds. Author Institution: Department of Chemistry, Texas Technological College Wed, 01 Jan 1969 00:00:00 GMT http://hdl.handle.net/1811/15864 1969-01-01T00:00:00Z Wilde, R. E. Ghosh, S. N. http://hdl.handle.net/1811/15863 INFRARED SPECTRA AND STRUCTURES OF THE NOBLE GASESMETHANE MIXED CRYSTALS. Chamberland, A.; Cabana, A. The infrared spectra of methane dissolved in the solid gases have been obtained at various concentrations in the range 0.06% to 55%. While at low concentrations the spectra of the three different systems resemble each other closely, at high concentrations the spectra are different. The influence of the molecular concentration on the fine structure of the asymmetric stretching vibration of methane will be discussed in terms of the structure of the mixed solutions. Author Institution: D\'{e}partment de Chimie, Universit\'{e} de Sherbrooke Wed, 01 Jan 1969 00:00:00 GMT http://hdl.handle.net/1811/15863 1969-01-01T00:00:00Z Chamberland, A. Cabana, A. http://hdl.handle.net/1811/15862 INFRARED AND RAMAN SPECTRA OF SILANE IN THE CONDENSED PHASES. Belzile, R.; Cabana, A.; Fournier, R. P.; Savoie, R. The infrared and Raman spectra of silane in its condensed phases have been obtained. The most interesting features are seen on the spectra of the crystal in phase II. The crystal structure is unknown. The spectra will be interpreted in terms of possible site and factor groups. Author Institution: D\'{e}partment de Chimie, Universit\'{e} de Sherbrooke; D\'{e}partment de Chimie, Universit\'{e} Laval Wed, 01 Jan 1969 00:00:00 GMT http://hdl.handle.net/1811/15862 1969-01-01T00:00:00Z Belzile, R. Cabana, A. Fournier, R. P. Savoie, R. http://hdl.handle.net/1811/15861 OPTICAL PHONONS AND PHASE TRANSITION OF THALLOUS IODIDE. Lowndes, R. P.; Perry, C. H. Far infrared transmittance and reflectance and Raman spectroscopic measurements have been made on polycrstalline thallous iodide in the temperature range $5^{\circ}-550^{\circ}K$. In particular, the spectroscopic investigations have been used to study the 4 molecule/unit cell $D^{17}_{2h}$ (Cmem) orthorhombic structure transition to the $O^{1}_{b}$ (Pm3m) CsCl structure which occurs near $445^{\circ}K$. In the orthorhombic structure one infrared active transverse optic mode and six Raman active modes were observed; group theoretical predictions indicate that there should be three infrared active and six Raman active modes. In the CsCl structure a single infrared transverse optic mode is still found but displaced to much lower frequencies than the mode observed below the transition temperature. The Raman spectra in the CsCl structure is purely second order. A significant hysteresis is observed in traversing the orthorhombic-CsCl phase transition. This work was supported by NASA grant NGR 22-011-051.; Author Institution: Physics Department, Northeastern University Wed, 01 Jan 1969 00:00:00 GMT http://hdl.handle.net/1811/15861 1969-01-01T00:00:00Z Lowndes, R. P. Perry, C. H. http://hdl.handle.net/1811/15860 MEASURING UNIAXIAL SPECTRAL DIELECTRIC RESPONSE: APPLICATIONS TO CALCITE $CaCO_{3}$ AND TYSONITE $LaF_{3}$. Parrish, J. F.; Perry, C. H. Often it is not possible or convenient to orient a crystal's optic axis precisely parallel or perpendicular to a large single crystal face. Furthermore, it can be shown both theoretically and experimentally that even rather small misalignments of an optic axis (less than five are degrees) can lead to large, easily measurable but possibly spurious effects. Nevertheless, quantitative and qualitative analysis of the measured spectra is possible, as it can be proved that the zeros (longitudinal optical frequencies) of the effective spectral dielectric response must occur at the zeros of the characteristic spectral dielectric response functions defined parallel and perpendicular to the optic axis, independent of the angle between the optic axis and crystal face. Moreover, the characteristic dielectric response functions can be calculated analytically from the experimentally measured effective spectral dielectric response functions of the ordinary and extraordinary rays reflected or transmitted by a single crystal face. The polarized far infrared transmittance and reflectance of calcite, which has strong anisotropics at high lattice frequencies ($\sim 1500 cm^{-1}$), and of tysonite, which has strong anisotropics at low lattice frequencies ($\sim 100cm^{-1}$), illustrate some of the effects predicted theoretically. This work was supported in part by the U. S. Air Force (ESD Contract AF 19(628)-69-C-0081) and NASA grant NGR 22-011-051 at Northeastern University and the Joint Services Electronics Program (Contract DA28-043-AMC 02536 (E) at M.I.T. J. F. Parrish is a Visiting Research Associate, Department of Physics, Northeastern University.; Author Institution: Research Laboratory of Electronics, Massachusetts Institute of Technology; Department of Physics, Northeastern University Wed, 01 Jan 1969 00:00:00 GMT http://hdl.handle.net/1811/15860 1969-01-01T00:00:00Z Parrish, J. F. Perry, C. H. http://hdl.handle.net/1811/15859 RAMAN SPECTRA OF ALKALI HALIDES AND SOME OF THEIR MIXED CRYSTALS. Fertel, Jeanne H.; Perry, C. H. The Raman spectra of room temperature KI RbI, and $Kcl_{1-x}Br_{x}$ (with $x=0,.08,.25,.5,.75,.92$, and 1.0) single crystals have been observed from $30-400 cm^{-1}$ frequency shift from the exciting line. These measurements were made with a Spex double monochromator using He-Ne excitation. No first order spectrum is expected for these crystals and we have assigned the observed peaks to two-phonon combinations and overtones at various symmetry points in the Brillouin zone. Experimental values for the critical point frequencies are available only for KBr. For KCl and KI we have used the frequencies calculated by Karo and Hardy (but these values are expected to be accurate only to about 10 per cent for the acoustic modes and 40 per cent for the optic modes). The assignments for the mixed crystal spectra were made by comparison, i.e., it was expected that the peaks in the KCl spectrum would vary smoothly into the KBr peaks as the mole fraction of KBr was increased. No frequencies, either calculated or experimental, are available for RbI, but we have been able to assign the RbI spectrum by comparison with the KI spectrum which it closely resembles. This work was supported in part by the NASA grant NGR 22 011-051 at Northeastern University and the Joint Services Electronics Program (Contract DA28-043-AMC 02536 (E) at M.I.T. Jeanne H. Fertel is a Visiting Research Associate, Department of Physics, Northeastern University.; Author Institution: Research Laboratory of Electronics, Massachusetts Institute of Technology; Department of Physics, Northeastern University Wed, 01 Jan 1969 00:00:00 GMT http://hdl.handle.net/1811/15859 1969-01-01T00:00:00Z Fertel, Jeanne H. Perry, C. H. http://hdl.handle.net/1811/15858 THEORY OF A NOVEL ODD-PARITY RAMAN EFFECT: DEPOLARIZATION AND ROTATIONAL STRUCTURE STUDIED BY RACAH'S TENSOR ALGEBRA. Chiu, Ying-Nan Raman Scattering was treated as a two-photon process in quantum electrodynamics. A novel scattering mechanism that involves one photon in an electric dipole mode of radiation (R) and one photon in a magnetic dipole mode (M, or electric quadrupole mode) has been worked out. Because the electric dipole transition operator has odd parity and the magnetic dipole (or electric quadrupole) operator has even parity, the initial and final electronic states in this mechanism are of opposite parities. This is in contrast to the conventional vibrational or rotational Raman Effect which involves both photons in the electric dipole mode and in which the initial and final electronic states are the same (and of the same parity). When the initial and final electronic states are of different energies, this mechanism gives rise to an odd-parity electronic Raman Effect. When the initial and final electronic states are the same, this mechanism can give rise to the vibrational and rotational Raman Effect for optically active molecules for which the second order transition matrix element $(O|R|b) (b|M|O)$ is non-vanishing. For random molecular system, the depolarization ratios for linearly polarized light and the reversal coefficients for circularly polarized light have been derived for arbitrary observation directions. For quantized symmetric top and spherical top molecules, the rotational structure for this novel Raman Scattering has also been derived. The derivation made use of the coupling of irreducible tensor, the properties of the rotation matrices and the symmetry and sum rules of Clebsch-Gordan $coefficients.^{1}$ Such use of modern angular momentum techniques shows an improvement of clarity over the early use of circular coordinates and direction consines by Placzek and Teller. These new techniques yield results expressible in terms of well known tabulated functions and are capable of extension to multi-photon (hyper)Raman Effects. This work was supported in part by the National Science Foundation and in part by the Petroleum Research Fund, American Chemical Society. Ying-Nan Chiu is an Alfred P. Sloan Research Fellow. $^{1}$ See for example Y.-N. Chiu, J. Chem. Phys. 41, 3285 (1964);ibid. 48, 5702 (1968).; Author Institution: Department of Chemistry, The Catholic University of America Wed, 01 Jan 1969 00:00:00 GMT http://hdl.handle.net/1811/15858 1969-01-01T00:00:00Z Chiu, Ying-Nan http://hdl.handle.net/1811/15857 VIBRATIONAL SPECTRA OF CRYSTALLINE CARBON SUBSULFIDE AND ITS VIBRATIONAL POTENTIAL FUNCTION. Bates, John B.; Smith, William Hayden Direct observation of the fundamental, and first and second overtones of $\nu_{\tau}$, the central carbon bending mode, in the polycrystalline spectra of $C_{3}S_{2}$ at $85^{\circ} K$ provides the basis for a discussion of the potential function for this low frequency vibration. Additional spectroscopic evidence is cited for the existence of a barrier of barrier of height $\left( \frac{h}{2\pi}\right)\omega_{\tau}$ at the linear configuration, and an interpretation of the data in terms of a ``quasi-linear'' model is presented. Present address for John B. Bates: Department of Chemistry, University of Maryland, College Park, Maryland. Present address for William Hayden Smith: Department of Astrophysical Sciences, Princeton University, Princeton, New Jersey.; Author Institution: Department of Chemistry, University of Maryland; Department of Astrophysical Sciences, Princeton University Wed, 01 Jan 1969 00:00:00 GMT http://hdl.handle.net/1811/15857 1969-01-01T00:00:00Z Bates, John B. Smith, William Hayden http://hdl.handle.net/1811/15856 INFRARED SPECTRA OF SOLID SODIUM AND LITHIUM NITRATES. Eckhardt, R.; Eggers, D. F.; Barone, A.; Slutsky, J. The infrared spectrum of single crystals of sodium and lithium nitrate has been observed as a function of temperature, pressure, polarization, direction of propagation, sample size, and isotopic composition. An interpretation of the structure and dependence on direction of propagation of the very intense $\nu_{3}$ absorption is offered. An assignment of the rich multiphonon spectrum based on the observed isotope shifts is suggested and the pressure dependence of the fundamental frequencies is discussed in terms of a dipolar coupling model. Author Institution: Department of Chemistry, University of Washington Wed, 01 Jan 1969 00:00:00 GMT http://hdl.handle.net/1811/15856 1969-01-01T00:00:00Z Eckhardt, R. Eggers, D. F. Barone, A. Slutsky, J. http://hdl.handle.net/1811/15855 INFRARED SPECTRA OF THE POLYMORPHIC FORMS OF ZIRCONIA POWDERS Phillippi, Conrad M.; McDevitt, Neil T. Powder samples must be employed when a crystalline materials under study is not available as a thin film or a large single crystal with oriented optically polished surfaces for infrared transmission and reflection measurements. Zirconium dioxide powders which occur in the cubic, tetragonal and monoclinic phases have been investigated to isolate the infrared frequencies characteristic of the various polymorphs. It is shown that the reflection spectrum of a bulk sample of stabilized cubic zirconia is a good first approximation to its powder transmission spectrum. This provides the basis for interpreting the other powder spectra in terms of infrared dispersion theory. Preliminary Raman spectra are presented, and the experimental vibrational spectra are compared with the activity predicted by factor group theory. The infrared spectra of monoclinic zirconias are shown to be very sensitive to lattice strain. Author Institution: Air Force Materials Laboratory (MAYA), Wright-Patterson AFB Wed, 01 Jan 1969 00:00:00 GMT http://hdl.handle.net/1811/15855 1969-01-01T00:00:00Z Phillippi, Conrad M. McDevitt, Neil T. http://hdl.handle.net/1811/15854 VIBRATIONAL FREQUENCIES OF THE OH- AND SH- IN ALKALI HALIDE SOLID SOLUTIONS. Apple, Bernard A.; Morgan, H. W. A molecular orbital calculation has been applied to the impurities $OH^{-}$ and $SH^{-}$ and their perturbing alkali halide lattice environments. The impurities were described by free state molecular wave functions of the Roothan LCAO-MO form, and expressions for the various lattice interactions derived using first order perturbation theory. In one case, this led to a one-electron, three-center integral, for which a method was developed to conveniently obtain the solution. Computer programs were written for evaluation of the lattice interactions. The equilibrium energies, internuclear separations, and vibrational frequencies were computed for several possible impurity positions in the lattices. Single crystals of several alkali halides were grown doped with OH- and SH-, and infrared absorption spectra obtained at temperatures from $30^{\circ}K$ to $300^{\circ}K$. Using the calculated energy values and a comparison of the observed and calculated frequency shifts from lattice to lattice, it was shown that the $OH^{-}$ and $SH^{-}$ are aligned along the 100 symmetry axis of the face centered cubic crystals, with the center of mass displaced. The displacement of the center of mass increases with the lattice constant. The importance of a molecular representation, compared to the classical point representation, will be discussed. This research was sponsored by the U. S. Atomic Energy Commission under contract with Union Carbide Corporation. Present address of Bernard A. Apple: E. I. du Pont de Nemours and Company, Experimental Station, Wilmington, Delaware.; Author Institution: Department of Physics and Astronomy, University of Tennessee; Department of Physics and Astronomy, Oak Ridge National Laboratory Wed, 01 Jan 1969 00:00:00 GMT http://hdl.handle.net/1811/15854 1969-01-01T00:00:00Z Apple, Bernard A. Morgan, H. W. http://hdl.handle.net/1811/15853 THE HYPER-RAMAN SPECTRUM OF THE LATTICE MODES OF $NH_{4} Cl$. Maker, P. D.; Savage, Chandra Using a pulsed ruby laser source and electronic data accumulation, the lattice mode, inclastic harmonic light scattering spectrum of $NH_{2}Cl$ has been measured, both at room temperature and below its phase transition temperature of $-30^{\circ} C$. The libration band, both Raman and IR forbidden, is active in this spectrum, and is observed at $375 cm^{-1}$. In addition, the LO band is seen, at $280 cm^{-1}$. In the low temperature, ordered phase, a strong broad band centered at $100 cm^{-1}$ is found, but not identified. Author Institution: Scientific Research Staff, Ford Motor Company Wed, 01 Jan 1969 00:00:00 GMT http://hdl.handle.net/1811/15853 1969-01-01T00:00:00Z Maker, P. D. Savage, Chandra http://hdl.handle.net/1811/15852 A VIBRATIONAL ANALYSIS OF THE INFRARED AND RAMAN SPECTRA OF OXALYL BROMIDE IN THE CRYSTALLINE AND FLUID STATES. Baglin, Frank G.; Durig, J. R. The infrared and Raman spectra of oxalyl bromide, $(COBr)_{2}$, have been recorded between 4000 and $33 cm^{-1}$. The infrared spectra have been examined in the solid, liquid, and gaseous states. The Raman spectra of the solid and liquid states have been observed and qualitative depolarization ratios have been measured. The vibrational spectrum of the crystalline materials has been interpreted on the basis of $C_{2h}$ molecular symmetry and a $C^{5}_{2h}$ space group symmetry. However, in the fluid states both the $C_{2h}$ and $C_{2v}$ molecular symmetries appear to be present, in contrast to earlier work reported on this system. In support of the crystallographic workers' report of an intermolecular charge-transfer phenomenon involving the bromine and oxygen atoms, we have observed a continual decrease in the $A_{g}$ carbonyl stretching frequency by means of a variable temperature laser Raman cell. Furthermore, all symmetry allowed external lattice modes have been observed in the far infrared spectrum and at least four of the six Raman active external lattice modes have also been recorded. Author Institution: Department of Chemistry, University of Nevada; Department of Chemistry, University of South Carolina. Wed, 01 Jan 1969 00:00:00 GMT http://hdl.handle.net/1811/15852 1969-01-01T00:00:00Z Baglin, Frank G. Durig, J. R. http://hdl.handle.net/1811/15851 ELECTRONIC STRUCTURE OF $ScF_{2}$ AND $TiF_{2}$. Gole, James L.; Hayes, Edward F.; Dyke, Maurice Ab Initio LCAO-MO SCF calculations using a contracted Gaussian basis are reported for several low-lying electronic states of $ScF_{2}$ and $TiF_{2}$. These calculations demonstrate the importance of 4p orbitals for the determination of the equilibrium bond angle and spectra of these species. Various possibilities for the electronic configuration of the ground state are considered and the qualitative features of the spectra are discussed. Author Institution: Department of Chemistry, Rice University Wed, 01 Jan 1969 00:00:00 GMT http://hdl.handle.net/1811/15851 1969-01-01T00:00:00Z Gole, James L. Hayes, Edward F. Dyke, Maurice http://hdl.handle.net/1811/15850 MILLIMETER SPECTROSCOPY OF OZONE. Lichtenstein, M.; Gallagher, J. J.; Clough, S. A.; Rothman, Laurence S. The millimeter wave spectrum of ozone has been observed in the region from 50 GHz to 316 GHz. Sixty-five previously unobserved lines have been measured by video techniqes employing Fabry-Perot interferometers and glass absorption cells. The Stark effect has been performed on eleven transitions using a parallel plate spectrometer; Zeeman measurement have been performed for five transitions. Calculation of transition frequencies, dipole moment and g-factor from the data is discussed. Author Institution: Electromagnetics Research Laboratory, Martin Marietta Corporation; Electromagnetics Research Laboratory, Air Force Cambridge Research Laboratories Wed, 01 Jan 1969 00:00:00 GMT http://hdl.handle.net/1811/15850 1969-01-01T00:00:00Z Lichtenstein, M. Gallagher, J. J. Clough, S. A. Rothman, Laurence S. http://hdl.handle.net/1811/15849 MEASUREMENT OF DEPOLARIZATION RATIOS IN RAMAN SPECTRA. Bulkin, Bernard J. Although crystalline powders give excellent laser excited Raman spectra, it has not been possible to measure the depolarization ratios because the Raman lines are depolarized by scattering off other crystal faces. This difficulty can be overcome by immersion of the powder in a medium of like refractive index. The application of this method to several different types of materials will be illustrated. The use of a digital ratemeter to rapidly measure depolarization ratios with high accuracy and well defined standard deviation will be discussed. Digital methods also enable one to obtain good Raman spectra and accurate depolarization ratios in samples of high background. Author Institution: Department of Chemistry, Hunter College of the City University of New York Wed, 01 Jan 1969 00:00:00 GMT http://hdl.handle.net/1811/15849 1969-01-01T00:00:00Z Bulkin, Bernard J. http://hdl.handle.net/1811/15848 FOREIGN GAS BROADENING AND SHIFTING IN HF. Wiggins, T. A.; Griffin, N. C.; Arlin, E. M. The broadening and shifting of lines in the 2-0 band of HF have been investigated for argon, krypton and xenon at room temperature and $150^{\circ}$ C. The shifts measured are in accord with the results of Jaffe, Rosenberg and Hirschfeld in that the shifts with xenon are smaller than with krypton as the foreign gas. This is contrary to the results found in HCl. Line broadening studies show that with argon the results are as would be expected from comparison with HCl. However, with xenon the broadening coefficient increases with increasing J. With krypton the broadening coefficient increases for high J lines. Work on the 1-0 band is in progress. Author Institution: Department of Physics, Pennsylvania State University Wed, 01 Jan 1969 00:00:00 GMT http://hdl.handle.net/1811/15848 1969-01-01T00:00:00Z Wiggins, T. A. Griffin, N. C. Arlin, E. M. http://hdl.handle.net/1811/15847 ESTIMATION OF HARMONIC FREQUENCIES OF $NH_{3}, PH_{3}, AsH_{3}, SbH_{3}, ND_{3}, PD_{3}, AsD_{3}$ AND $SbD_{3}$ FROM THE OBSERVED FUNDAMENTAL FREQUENCIES. Gamo, Itaru The vibrational harmonic frequencies of these molecules have been estimated from the observed anharmonic frequencies by aid of the method proposed by $us^{1}$ to compute the harmonic frequencies of $A_{1}$ vibrations of $H_{2}O, D_{2}O, H_{2}S, H_{2}Se$ and $D_{2}Se$. This method utilizes the Wilson's splitting of the high frequency from the low in his G matrix for vibration calculation, combined with the Dennison's isotopic rule which states that the anharmonic correction is proportional to the harmonic frequency. The obtained values for $\nu_{1}$ vibrations are as follows (in $cm^{-1}$): $\begin{array}{lllll}NH_{3} & 3466.29 && ND_{3} & 2487.79\\ PH_{3} & 2471 &&PD_{3} & 1771\\ AsH_{3}& 2202.3 && AsD_{3} &1567.2\\ SbH_{3} &1981.7 && SbD_{3}& 1407.1\\\end{array}$ These values as well as those for $\nu_{2}, v_{3}$, and $v_{4}$ vibrations have been examined in comparison with the older values obtained by other methods. Finally, a dependence of the anharmonicity upon the effective nuclear charge for the valence electron of the central atom has been considered. $^{1}$ I. Gamo, J. Mol. Spectry 30, 216 (1969).; Author Institution: Department of Chemistry, University of Maryland Wed, 01 Jan 1969 00:00:00 GMT http://hdl.handle.net/1811/15847 1969-01-01T00:00:00Z Gamo, Itaru http://hdl.handle.net/1811/15846 LATTICE DYNAMICS OF THIOUREA. Bandy, Alan; Cessac, Gerald; Lippincott, Ellis R. Frequencies of the lattice vibrations have been measured for each of the five polymorphic forms of thiourea. Raman spectra of an oriented single crystal have made possible an unambiguous assignment of the observed Raman active lattice modes. The temperature dependence of the frequencies and relative Raman intensities will be discussed. Evidence indicating considerable mixing of the translational and librational rigid motions will be presented. Author Institution: University of Maryland, Department of Chemistry Wed, 01 Jan 1969 00:00:00 GMT http://hdl.handle.net/1811/15846 1969-01-01T00:00:00Z Bandy, Alan Cessac, Gerald Lippincott, Ellis R. http://hdl.handle.net/1811/15845 LATTICE DYNAMICS OF MOLECULAR CRYSTALS. II. CYANOGEN BROMIDE. Bandy, Alan; Bates, John B.; Lippincott, Ellis R.; McMurry, H. L. The results of a measurement of the polarized Raman spectrum of single crystal CNBr at $300^{\circ} K$ will be described. Using the procedures outlined in I above, we have calculated the crystal vibrations for $k=0$ and have refined a simple valence force potential based on all the currently known optical modes. The dispersion curves for the [100] and [001] directions were calculated from the ``optically'' refined valence force field. The results of the dispersion calculations and the effects of including long-range coulomb forces to the valence force field will be described. Author Institution: Department of Chemistry, University of Maryland; Idaho Nuclear Corporation, Idaho Falls, Idaho Wed, 01 Jan 1969 00:00:00 GMT http://hdl.handle.net/1811/15845 1969-01-01T00:00:00Z Bandy, Alan Bates, John B. Lippincott, Ellis R. McMurry, H. L. http://hdl.handle.net/1811/15844 FLUORESCENCE AND LIFETIME STUDIES OF EXCIMERS IN POLYVINYL CARBAZOLE. Bauser, H.; Klopffer, W. The fluorescence spectrum of solid-state polyvinyl carbazole (PVCA) is of the excimer type whereas in solution both mirror-image and excimer-fluorescence spectra can be observed. The excimer-fluorescence decay time after flash excitation was found to be approximately $4\times 10^{-8}$ sec. Small amounts of perylene, hexachloro-p-xylene, and trinitro fluorenone in PVCA reduce the quantum efficiency (y) of the PVCA fluorescence but leave the decay time unaffected. The quenching factor $Q = yo/y(c)-1$ depends linearly on the guest concentration (c). The results are interpreted in terms of energy transfer by monomer-exciton diffusion involving two competitive traps: excimer forming sites and guest molecules. Author Institution: Battelle-Institut, Frankfurt a. Wed, 01 Jan 1969 00:00:00 GMT http://hdl.handle.net/1811/15844 1969-01-01T00:00:00Z Bauser, H. Klopffer, W. http://hdl.handle.net/1811/15843 INFRARED SPECTRAL ABSORPTION COEFFICIENT DATA FOR WATER VAPOR. Herget, William F.; Muirhead, J. S. An experimental program is described in which the spectral absorption coefficients of $H_{2}O$ were determined in the 1 to 8 micron spectral range at temperatures from 575 to $1250^{\circ} K$, at path lengths up to one meter, and at pressures up to one atmosphere. Foreign gas broadening of $H_{2}O$ by $H_{2}, CO$, and $CO_{2}$ was measured over portions of the above ranges. Experimental details, such as the grating spectrometer, absorption cells, and data collection procedures are presented, along with a description of the computerized data reduction program. Samples of the high resolution spectra obtained will be shown. This research was supported in part by the National Aeronautics and Space Administration, Marshall Space Flight Center, under Contracts NAS8-20397 and NAS8-19. The contract monitor was Mr. Robert M. Huffaker.; Author Institution: Research Division Rocketdyne, A Division of North American Rockwell Corporation Wed, 01 Jan 1969 00:00:00 GMT http://hdl.handle.net/1811/15843 1969-01-01T00:00:00Z Herget, William F. Muirhead, J. S. http://hdl.handle.net/1811/15842 VIBRATIONAL-ROTATIONAL INTERACTIONS IN THE INFRARED SPECTRUM OF $C_{2}D_{2}$. Pliva, J.; Gherskiti, S.; Rao, K. Narahari The infrared spectrum of dideuteroacetylene, $C_{2}D_{2}$, is considerably complicated by the presence of numerous ``hot'' bands originating from the two low-lying levels, $0001^{1}0^{0} (\Pi_{g})$ and $0000^{0}1^{1} (\Pi_{u})$. Rotational analysis of these ``hot'' bands brought to light strong interactions among states with $(v_{4} + v_{5})\geqslant 2$: for example, in the group of interacting states $0002^{0}0^{0}, 0002^{2}0^{0}, 0000^{0}2^{0}$, and $0000^{0}2^{2}$, the separation between $0002^{0}0^{0}$ and $0002^{2}0^{0}$ is only $\sim 0.35 cm^{-1}$ resulting in a very strong perturbation of the rotational levels of the $\Delta_{g}(c)$ and $\Sigma^{+}_{g}$ states (the $\Delta_{g}(d)$ state shows regular behaviour). Transitions involving $\Sigma^{-}_{u}$ and $\Sigma^{-}_{g}$ states have also been identified for the first time in a vibrational-rotational spectrum.; Author Institution: Division of Pure Physics, National Research Council of Canada; Department of Physics, The Ohio State University Wed, 01 Jan 1969 00:00:00 GMT http://hdl.handle.net/1811/15842 1969-01-01T00:00:00Z Pliva, J. Gherskiti, S. Rao, K. Narahari http://hdl.handle.net/1811/15841 ALGEBRAIC THEORY OF POTENTIAL FUNCTIONS. APPLICATION TO CARBON DIOXIDE. Chila, Z.; Chedin, A. The great difficulties inherent in a very accurate determination of the potential function of a polyatomic molecule from its infrared spectrum, have led us to develop an original method allowing the treatment of pure numbers as well as non-commutative quantum operators and to adhere very closely to the internal structure of modern computers in order to reduce computation time to a minimum. This method is based upon the principles of general algebra and has been applied to carbon dioxide. The passage from the expansion of the potential function with respect to exact internal coordinates to the vibrational levels is performed by means of a very large and extensive ALGOL program. The principal steps performed by this program are: 1)---The first expansion of the potential function with respect to internal coordinates is reexpanded with respect to normal coordinates (to the fourth order of approximation). 2)---The kinetic energy (vibrational contribution only) is then expanded with respect to normal coordinates using the commutation rules existing between these coordinates and their conjugate momenta. By adding this expansion to the preceding one we get the untransformed Hamiltonian (H) expansion with respect to normal coordinates. 3)---The perturbation treatment of this operator is then carried out by means of two successive contact transformations which are automatically performed taking into account all of the accidental resonances one wishes to consider. At the end of this step we obtain the normal-coordinates expansion of the twice-transformed Hamiltonian $H^{\dagger}$. 4)---Then the program computes the matrix elements of $H^{\dagger}$, and determines the spectroscopic constants of the molecule. 5)---With these constants the program constructs the factorized energy matrix and its diagonalization gives us the calculated vibrational levels and the initial norm. 6)---Having determined the partial derivatives of each calculated level with respect to the coefficients appearing in the original expansion of the potential function, the program computes the corrections to the initial values of the potential coefficients. The convergence is very fast. For most of the levels the differences between experimental and calculated energy values are within the limits of the experimental errors. Let us notice that: a)---the potential function we have presently at our disposal (and which was determined by using only $^{12}C ^{16}O_{2}$ data) allows a very good determination of the vibrational levels for $^{13}C ^{16}O_{2}$, and more generally, for all of the other symmetrical or non-symmetrical isotopic species. b)---despite the size of the program (5000 cards), one iteration is performed in two minutes with a 3600 C.D.C. computer (three times faster than a 7090 I.B.M. computer). This is accounted for by the fact that the program structure is very well suited to the computer structure. A very large part of the computation needs to be done only once and, moreover, gives results which are valid for all the triatomic linear molecules. The experimental results we have used in this computation were obtained in the past or more recently by C. P. Courtoy, T. K. McCubbin, Jr., K. Narahari Rao, and by W. S. Benedict who studied very extensively the Venus spectra recorded by J. and P. Connes two years ago. Author Institution: Laboratory of Molecular Spectroscopy, Czechoslovak Academy of Sciences; Laboratorie de Spectroscopie, Mol\'eculaire Facult\'e des Sciences Tour Wed, 01 Jan 1969 00:00:00 GMT http://hdl.handle.net/1811/15841 1969-01-01T00:00:00Z Chila, Z. Chedin, A. http://hdl.handle.net/1811/15840 RADIATIVE LIFETIMES IN MOLECULAR SYSTEMS WHICH UNDERGO LARGE CONFIGURATION CHANGE IN THE EXCITED STATE. El-Bayoumi, M. Ashraf; Dalle, Jean-Paul; O'Dwyer, M. F. Large configuration change in the excited state of a molecular system can be an important factor in causing large discrepancies between observed radiative lifetimes and lifetimes calculated from the corresponding integrated absorption intensity. We have measured fluorescence lifetimes and quantum yields in different solvents for a number of molecules. Our results indicate that $r_{o}$, the radiative fluorescence lifetime, increases with an increase of the polarity of the solvent. At low temperatures, when the solvent cage reorientation cannot occur during the lifetime of the excited state, the emission arises from a Franck-Condon state which has an equilibrium configuration similar to that of the ground state. Under these conditions $\tau_{o}$ decreases and the emission becomes blue shifted. Author Institution: Biophysics Department, Michigan State University Wed, 01 Jan 1969 00:00:00 GMT http://hdl.handle.net/1811/15840 1969-01-01T00:00:00Z El-Bayoumi, M. Ashraf Dalle, Jean-Paul O'Dwyer, M. F. http://hdl.handle.net/1811/15839 TRANSITION MOMENT DIRECTIONS OF ADENINE HYDROCHLORIDE. Clark, Leigh B.; Chen, Holly Ho Absorption spectra for light polarized along the a, b and c crystallographic directions of adenine-HCl single crystals have been obtained by a Kramers-Kronig transformation of reflection spectra ($6500{\AA}-1850{\AA}$). The transition moment directions and oscillator strengths of the four observed bands are obtained. Crystal perturbations leading to intensity borrowing among bands and internal field effects are considered. The derived single molecule properties are used to calculate the optical properties of polyadenylic acid double helix. Author Institution: Department of Chemistry, University of California Wed, 01 Jan 1969 00:00:00 GMT http://hdl.handle.net/1811/15839 1969-01-01T00:00:00Z Clark, Leigh B. Chen, Holly Ho http://hdl.handle.net/1811/15838 REFLECTION SPECTRA OF ANTHRACENE. Clark, Leigh B. Polarized reflection spectra from the (001), (201) and (110) faces of anthracene single crystals have been measured ($6500{\AA}-1820{\AA}$), and the corresponding absorption spectra have been obtained through Kramers-Kronig analyses. The a-axis and b-axis spectra are essentially in quantitative agreement with the direct absorption measurements of Lyons and Morris.$^{1}$ The derived absorption spectrum for radiation polarized along the intersection of the ac plane and the (201) face shows a very strong band at $40,000 cm^{-1} (\epsilon_{max}\sim 125,000)$. Since this band is presumably derived from the intense long axis polarized molecular transition at about the same energy, our results suggest that the theoretical arguments which predict this band shifted into the vacuum ultraviolet in the crystal cannot be correct. $^{1}$ L. E. Lyons and G. C. Morris, J. Chem. Soc. (1959) 1551.; Author Institution: Department of Chemistry, University of California Wed, 01 Jan 1969 00:00:00 GMT http://hdl.handle.net/1811/15838 1969-01-01T00:00:00Z Clark, Leigh B. http://hdl.handle.net/1811/15837 LATTICE DYNAMICS OF MOLECULAR CRYSTALS. I. HEXACHLORO-BENZENE. Bates, John B.; Bandy, Alan; Thomas, Dwaine, M.; Lippincott, Ellis R.; McMurry, H. L. A brief description of the method used to calculate the dispersion relations for crystal vibrations based on the valence force model will be $presented.^{1}$ The polarized Raman spectrum of a single crystal of hexachlorobenzene will be discussed, and the results of a preliminary analysis of the lattice dynamics based on the valence force model will be given. $^{1}$ H.L. McMurry, A.W. Solbrig, Jr., J.K. Boyter and C. Noble, J. Phys. Chem. Solids 28, 2359 (1967).; Author Institution: Department of Chemistry, University of Maryland, College Park; Idaho Nuclear Corporation, Idaho Falls, Idaho Wed, 01 Jan 1969 00:00:00 GMT http://hdl.handle.net/1811/15837 1969-01-01T00:00:00Z Bates, John B. Bandy, Alan Thomas, Dwaine, M. Lippincott, Ellis R. McMurry, H. L. http://hdl.handle.net/1811/15836 THE $\bar{A}{^{2}}A^{\prime} - \bar{X}{^{2}}A^{\prime\prime}$ SYSTEM OF HNF. Woodman, C. M. The absorption spectrum in the region $3800-5000\AA$ obtained in the flash photolysis of $HNF_{2}$ has been photographed at high resolution. The conclusions of the earlier $workers^{1}$ are confirmed, namely that it is due to HNF, which is bent in both ground and excited states. The band system consists of a single progression in the bending vibration $v_{2}$, and there are prominent ``axis-switching'' effects due to the large change in bond angle. The $\rho$-type doubling is interpreted in terms of interaction between ground and excited states, which correlate with the two (Renner) components of a linear $^{2}II$ state. The $v_{2}{^{\prime}} = 1$ state shows evidence of ``second-order rotational resonance'' with the $v_{3}{^{\prime}} = 1$ state. $^{1}$ P. L. Goodfriend and II. P. Woods. J. Mol. Spectry 20, 258 (1966).; Author Institution: Division of Pure Physics, National Research Council of Canada Wed, 01 Jan 1969 00:00:00 GMT http://hdl.handle.net/1811/15836 1969-01-01T00:00:00Z Woodman, C. M. http://hdl.handle.net/1811/15835 OPTICAL-RADIO FREQUENCY DOUBLE RESONANCE ON $A {^{1}}II$ CS. Field, R. W.; Bergeman, T.; Klemperer, William A CS molecular resonance lamp was used to optically pump the $v = 0$ vibrational level of the CS $A{^{1}}II$ state. Dipole moments and lambda doublings have been obtained for rotational levels $J = 3$ through 9 by Stark Effect-radio frequency resonance experiments. Resonance is detected by monitoring undispersed fluorescence to the $X {^{1}}\Sigma^{+}$ state. In conjunction with optical data$^{1}$ the measured lambda doublings were used to refine interaction matrix elements for the perturbation of $A^{1}II (v=0)$ by $a^{1}{^{3}}\Sigma^{+}$. These matrix elements in turn enable one to separate the very small $a{^{13}}\Sigma^{+}$ contribution from the measured dipole moments. A least squares fit to the individual moments measured with 0.3% precision yields $\mu_{11} = 0.65(3), \mu_{\Sigma} = 1.7 (12)$ Debye. $^{1}$ Barrow, R. F. et al., Ark. Fys, 18, 343 (1960).; Author Institution: Department of Chemistry, Harvard University Wed, 01 Jan 1969 00:00:00 GMT http://hdl.handle.net/1811/15835 1969-01-01T00:00:00Z Field, R. W. Bergeman, T. Klemperer, William http://hdl.handle.net/1811/15834 THE ALTERNATION WITH J OF ABSORPTION LINEWIDTHS IN THE $B^{3}II_{0_{u}}^{+}-X{^{1}}\Sigma_{g}^{+}$ BAND SYSTEM OF THE IODINE MOLECULE. Kroll, M.; Innes, K. K. We have begun an experimental study of the shapes of absorption lines in molecular electronic spectra. The instrument being used in this study is an ``Hypeac'' pressure scanning Fabry-Perot interferometer spectrometer whose resolving power has been demonstrated to be at least 750,000 (corresponding to a line-width of $0.024 cm^{-1}$) at $5500\AA$. The first absorption spectrum we have studied is the $B {^{2}}II_{0+}-X{^{1}}\Sigma_{g}^{+}$ transition of iodine vapor at about $5600\AA$. The smallest measured linewidths in this spectrum are about $0.030 cm^{-1}$ at total pressures of $100 \mu$ Hg. The linewidth alternates with the rotational quantum number J. being about $0.030 cm^{-1}$ for even $J^{\prime\prime}$ and $0.035 cm^{-1}$ for odd $J^{\prime\prime}$. We have attempted to explain the observed width and its alternation in terms of the interaction of the nuclear quadrupole moment of the iodine nuclei with the molecular electric field. Author Institution: State University of New York Wed, 01 Jan 1969 00:00:00 GMT http://hdl.handle.net/1811/15834 1969-01-01T00:00:00Z Kroll, M. Innes, K. K. http://hdl.handle.net/1811/15833 LASER-INDUCED RESONANCE FLUORESCENCE SPECTROSCOPY. Demtroder, W.; Zare, R. N.; McClintock, M. The argon ion laser lines at 4658, 4727, 4880, 4965, 5017 and $5145\AA$ are each found to excite one or more resonance fluorescence series of the $Na_{2} (X {^{1}}\Sigma_{g}^{+} - B {^{1}} II_{u})$ blue-green band system. Altogether, nineteen different fluorescence progressions have been identified and assigned v,J quantum numbers. The absolute wavenumbers of many of these emission lines have been measured interferometrically using a Fabry-Perot etalon crossed with a Bass-Kessler type spectrograph. A revised set of spectroscopic constants has been determined for both the upper and lower states which reproduce the observed term energies to better than $0.1 cm^{-1}$ on the average. Using these improved spectroscopic data, potential curves have been constructed for the B and X states of $Na_{2}$ by the Rydberg-Klein-Rees method. These potential curves are used in turn to compute Franck-Condon factors for the $Na_{2}$ B-X band system. Author Institution: Joint Institute for Laboratory Astrophysics; National Bureau of Standards Wed, 01 Jan 1969 00:00:00 GMT http://hdl.handle.net/1811/15833 1969-01-01T00:00:00Z Demtroder, W. Zare, R. N. McClintock, M. http://hdl.handle.net/1811/15832 LASER INDUCED FLUORESCENCE OF BaO. Sakurai, K.; Johnson, S. E.; Broida, H. P. Fluorescence spectra of the $A {^{1}}\Sigma - X {^{1}}\Sigma$ system of BaO excited by seven visible Ar-ion laser lines have been observed from the excitation lines to beyond 1000 nm. The experimental arrangement was similar to that previously $described.^{1}$ An ion laser with a prism reflector at one end of the optical resonator was used to obtain single line oscillation. BaO molecules were produced by gas phase chemical reactions between $O_{2}$ and Ba vapor in an inert gas at room temperature. Barium was vaporized in an alumina crucible in cylindrical electric heater. Ba vapor was cooled and carried to the reaction and fluorescence cell by He, $Ar, N_{2}$ gas in excess as compared to the amount of Ba atoms. Rotational lines in the vibrational bands in fluorescence series were well resolved (to $0.08\AA$). Rotational and vibrational assignments of the excitation transitions have been made as shown in Table I. Improved rotational and vibrational constants in the lower electronic state were obtained. $\omega_{e} y_{e}$ and $\delta_{e}$ were found to be 0.0045 and $4\times 10^{-5} cm^{-1}$, respectively while other constants are identical to previously measured values.$^{2}$ In addition to fluorescence, a weak chemiluminescence of the $A {^{1}}\Sigma - X {^{1}}\Sigma$ system of BaO was observed in this reaction. Studies have been made, from 0.4 to 40 torr, of the collision energy transfer to other rotational and vibration levels of the $A {^{1}}\Sigma$ state after optical pumping by laser lines. The transitions from $v^{\prime} = 0-12$ in $A {^{1}}\Sigma$ state to $v"" = 0-17$ in ground state were observed. Strong non-thermal distributions of rotational and vibrational populations were observed.[FIGURE] Work supported in part by the U. S. Air Force Research Projects Laboratory, Edwards Air Force Base. K. Sakurai is on leave from the Department of Physics, University of Tokyo, Japan. $^{1}$ K. Sakurai and H. P. Broida, J. Chem. Phys. 50, 2404 (1969). $^{2}$ A. Lagerqvist, E. Lind and R. F. Barrow, Proc. Phys. Soc. 63, 1132 (1950).; Author Institution: Department of Physics, University of California Wed, 01 Jan 1969 00:00:00 GMT http://hdl.handle.net/1811/15832 1969-01-01T00:00:00Z Sakurai, K. Johnson, S. E. Broida, H. P. http://hdl.handle.net/1811/15831 ABSORPTION SPECTRUM OF CF, 1500-2500{\AA}. White, William P.; Mathews, C. W. Observation of the CF spectrum in absorption has permitted us to extend the analyses of previously observed A and B $states^{1,2}$ and to obtain preliminary assignments for a new series of bands observed between 1500 and $1950{\AA}$. Rotational analysis of the (2,0) band of the $A ^{2}\Sigma^{+} - X ^{2}II$ system confirms an earlier vibrational $assignment^{3}$ and provides additional information about the predissociation of the $A ^{2}\Sigma^{+}$ state. Our observations of the B-X system supplements earlier unpublished $results^{4}$ and establishes the identity of the upper state as $^{2}\Delta$ (case b). A summary will be presented of our present interpretation of the bands below $1950{\AA}$. These bands are characterized by upper state B values comparable to those of the $A ^{2}\Sigma^{+}$ state and by evidence of predissociation or perturbation. Grateful acknowledgment is made to Dr. A. E. Douglas and his associates at the Division of Pure Physics, National Research Council, Ottawa, Canada for the use of their equipment in obtaining the data and to the donors of The Petroleum Research Fund, administered by the American Chemical Society, for partial support during the analysis of the data. $^{1}$ E. B. Andrews and R. F. Barrow, Proc. Phys. Soc. London A64, 481 (1951). $^{2}$ T. L. Porter, D. E. Mann and N. Acquista, J. Mol. Spectry, 16, 228 (1965). $^{3}$ B. A. Thrush and J. J. Zwolenik, Trans, Faraday Soc. 59, 582 (1963). $^{4}$ P. K. Carroll and R. D. Verma, private communication.; Author Institution: Department of Chemistry, The Ohio State University Wed, 01 Jan 1969 00:00:00 GMT http://hdl.handle.net/1811/15831 1969-01-01T00:00:00Z White, William P. Mathews, C. W.