Ab initio study of fast small-amplitude vibrations as functions of slow large-amplitude motions in CD3OH and comparison to CH3OH
Abstract Ab initio quantum chemical calculations generating a two-dimensional map of the energy surface and vibrational frequencies have been carried out for CD 3 OH and CH 3 OH over ranges of the torsional angle γ and the OH bend angle ρ. We have explored the frequency variation of the fast small-amplitude asymmetric ν 2 and ν 9 CD and CH stretching modes of E parentage as functions of the slow large-amplitude γ and ρ coordinates associated with the torsional and OH-bending modes that would form a degenerate e pair in the ρ=0° limit of COH linearity. The Gaussian09 program package was employed to calculate minimized energies, structures and Hessians on a grid of points with γ varying from 120° to 180° from the top to the bottom of the torsional potential barrier and ρ varying from 0° at linearity up to a 100° bend. The energies, average frequencies and frequency differences for each species have been fitted to a model combining Fourier expansions in the torsional angle with power-series in the OH-bend angle (Thapaliya et al., 2015) and the expansion constants are presented and compared for the two isotopologues. The conical intersection points of degeneracy between the ν 2 and ν 9 frequencies have been located for CD 3 OH, close to those known for CH 3 OH (Dawadi and Perry, 2014). For CD 3 OH, CD stretching frequencies calculated along the IRC torsional path from top to bottom of the barrier have been fitted to a high-order local mode model for comparison with earlier results for CH 3 OH (Xu, 2000), and A-E torsional splittings have been predicted for the three CD stretches. Highlights Ab initio 2-D torsion/OH bend map of energy surface for CD 3 OH and CH 3 OH. Energy, frequency terms Fourier fitted in torsion and by power-series in OH-bend. Conical intersections between ν 2 and ν 9 surfaces located for CD 3 OH. CD stretches fitted along torsional path and A-E torsional splittings predicted. Graphical abstract [DISPLAY OMISSION]
유료 다운로드의 경우 해당 사이트의 정책에 따라 신규 회원가입, 로그인, 유료 구매 등이 필요할 수 있습니다. 해당 사이트에서 발생하는 귀하의 모든 정보활동은 NDSL의 서비스 정책과 무관합니다.
원문복사신청을 하시면, 일부 해외 인쇄학술지의 경우 외국학술지지원센터(FRIC)에서
무료 원문복사 서비스를 제공합니다.
NDSL에서는 해당 원문을 복사서비스하고 있습니다. 위의 원문복사신청 또는 장바구니 담기를 통하여 원문복사서비스 이용이 가능합니다.
- 이 논문과 함께 출판된 논문 + 더보기