ANHARMONICITY CONSTANTS FOR THE METHYL $HALIDES^{*}$
Loading...
Date
1963
Journal Title
Journal ISSN
Volume Title
Publisher
Ohio State University
Abstract
“Because of some inconsistencies in the previous $work,^{1}$ we have redetermined the anharmonicity constants $x_{1}$ for the $CY_{3}X$ molecules (Y=H or D; X=F, CI, Br, or I), using the equations of Hansen and $Dennison.^{2}$ For the $a_{1}$ and e C-H stretching, and the e H-C-H bending, vibrations, the $x_{1}’s$ reported by $Dennison^{2}$ for $CH_{4}$ were used. For the $a_{1} C-X$ (diatomic-molecule-like) stretching vibration, several values of $x_{a}$ were selected in a range determined by the $x_{a}$ values of diatomic molecules containing similar atoms, and values of $x_{2}$ were calculated for each of these. The $\omega_{i}$ values were then obtained from the observed wave numbers $\sigma_{i}$ and the relation $\sigma_{i} = \omega_{i}(1 - x_{j})$. The six $x_{i}’s$ corresponding to those $\omega_{i}’s$ which best satisfied the Teller-Redlich product rule were then taken as the best values. The $x_{i}’s$ thus obtained for $\sigma_{1} (a_{1}), \sigma_{2}(a_{1}), \sigma_{3}(a_{1}), \sigma_{4}(e), \sigma_{5}(e),$ and $\sigma_{6}(e)$ wee respectively: [FIGURE] In the product rule, $\Pi _{i} \omega_{i}(CH_{3} X)/\Pi_{i} \omega_{i} (CD_{3}X) =|G^{CH_{2}X}|^{1/_{2}} |G^{CD_{2}X|^{1/_{2}}}|G^{CD_{1}X}|^{1/_{2}}$ to 5 significant figures for the $a_{1}$, and 4 for e, species. The present $x_{i}’s$ seem more consistent and meaningful than the previous values.”
Description
$^{*}$Aided by the National Science Foundation. $^{1}$T.S. Chang, Thesis, University of Michigan, 1954. $^{2}$G.E. Hansen and D.M. Dennison, J. Chem, Phys, 20, 313 (1952) $^{3}$D.M. Dennison, Rev. Mod. Phys. 18, 175 (1940).
Author Institution: Department of Physics, Illinois Institute of Technology
Author Institution: Department of Physics, Illinois Institute of Technology