Please use this identifier to cite or link to this item:

Show full item record

Files Size Format View
1994-WG-03.jpg 117.9Kb JPEG image Thumbnail of AUTOIONIZING RYDBERG STATES OF CaCl

Creators: Gittins, C.; Harris, N.; Field, R. W.
Issue Date: 1994
Publisher: Ohio State University
Abstract: Rotationally resolved, vibrational autoionization detected, optical-UV double resonance spectra of CaCl have been observed above the v=0 ionization threshold. The observed Rydberg states have $n^{*} >15$ and v=1. The experiment is a variation on traditional optical-optical double resonance (OODR) experiments in that the signal is produced by autoionization, rather than by UV fluorescence or a fluorescence dip. All spectra were recorded using $A^{2}\Pi_{3/2}-X^{2}\Sigma^{+}_{1/2} (0.0)$ PUMP $transitions^{1,2}$. The Rydberg-$A^{2}\Pi_{3/2} (1,0)$ transitions are in the near UV. Vibrational autoionization is found to be much more efficient than direct ionization from $A^{2}\Pi_{3/2}, v=0$ to $(CaCl)^{+}, v^{+}=0$. As the most useful $Ca^{35}Cl$ and $Ca^{37}Cl$ PUMP transitions are often coincident, double resonance does not always discriminate between the two isotopic species. The isotopomers are distinguished of Rydberg-$A^{2}\Pi_{3/2}$ transitions. Several series have been followed from $n^{*}-15$ through 43. The $n^{*}=16$ supercomplex has been analyzed in detail. The observed spectra cannot be explained in terms of pure-l $states^{3,4}$. An abrupt decrease in the density of observed transitions occurs near $n^{*}=25$. This effect is believed to be a result of the operating of a predissociation channel. The CaCl ionization potential has been (spectroscopically) determined to be 6.012(1) eV. The $(CaCl)^{+}$ rotational constant and vibrational frequency will also be reported.
Description: 1. L. E. Berg, L. Klynning, and H. Martin, Phys. Scr. 21, 173-178 (1980). 2. W. E. Ernst, J. O. Schrf\""{o}der, U. Buck, J. Kesper, and T. Seelemann, J. Mol. Spectrosc. 117, 342-354 (1986). 3. J. E. Murphy, J. M. Berg, A. J. Merer, N. A. Harris, R. W. Field, Phys. Rev. Lett. 65, 1861-1864 (1991). 4. N. A. Harris and C. Jungen, Phys. Rev. Lett. 70, 2549-2552 (1993).
Author Institution: Department of Chemistry, M.I.T.
Other Identifiers: 1994-WG-03
Bookmark and Share