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Title: A local mode study of ring puckering effects in the infrared spectra of cyclopentane
We report and interpret recently recorded high-resolution infrared spectra for the fundamentals of the CH 2 scissors and CH stretches of gas phase cyclopentane at −26.1 and −50 °C, respectively. We extend previous theoretical studies of this molecule, which is known to undergo barrierless pseudorotation due to ring puckering, by constructing local mode Hamiltonians of the stretching and scissor vibrations for which the frequencies, couplings, and linear dipoles are calculated as functions of the pseudorotation angle using B3LYP/6-311++(d,p) and MP2/cc-pVTZ levels of theory. Symmetrization ( D 5 h ) of the vibrational basis sets leads to simple vibration/pseudorotation Hamiltonians whose solutions lead to good agreement with the experiment at medium resolution, but which miss interesting line fractionation when compared to the high-resolution spectra. In contrast to the scissor motion, pseudorotation leads to significant state mixing of the CH stretches, which themselves are Fermi coupled to the scissor overtones.  more » « less
Award ID(s):
1900095
PAR ID:
10350692
Author(s) / Creator(s):
;
Date Published:
Journal Name:
The Journal of Chemical Physics
Volume:
156
Issue:
21
ISSN:
0021-9606
Page Range / eLocation ID:
214305
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
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