VIBRATIONAL ANALYSIS OF SUBSTITUTED AND PERTURBED MOLECULES. II. PLANAR $XY_{3}$ MOLECULES: APPLICATION TO $BCl_{3}, HBCl_{2}$, AND $DBCl_{2}$
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Date
1964
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Ohio State University
Abstract
The vibrational frequencies of isotopically substituted planar $XY_{3}$ molecules have been obtained using the Green's function and partioning techniques. Taking $HBCl_{2}$ as an ``isotopic'' species of $BCl_{3}$, we have calculated its spectrum, without invoking a force constant model. The excellent agreement between predicted and observed spectra indicates that even the force constant changes may be neglected as a first approximation. Using the information provided by the calculations, we have observed and identified five of the six $HBCl_{2}$ fundamentals: $\nu_{1}=762$ and $740 cm^{-1}, B^{10}-$ and $B^{11}-Cl$ symmetric stretches; $\nu_{2}=2617 cm^{-1}$, B-H stretch (no splitting); $\nu_{4}=1100$ and $1089 cm^{-1}, B^{10}-$ and $B^{11}-Cl$ asymmetric stretch; $\nu_{5}=892 cm^{-1} (B^{11}$ only), in-plane H deformation; and $\nu_{4}=795$ and $784 cm^{-1}$, out-of-plane deformation. Frequencies observed and identified for the deuterated compound are: $\nu_{2}=1969 cm^{-1}, B-D$ stretch; and $\nu_{6}=661$ and $645 cm^{-1}, B^{10}-B^{11}$ splitting. The calculations also indicate that the other frequencies we have not observed are hidden by $BCl_{3}$ bands, and that $\nu_{3}$, a $B-Cl$ bending mode is at $\approx 285-290 cm^{-1}$, outside the range of our instrument.
Description
Author Institution: North American Aviation Science Center