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Chemistry & Biochemistry Faculty Publications

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Infrared spectra

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A Local Mode Study Of Ring Puckering Effects In The Infrared Spectra Of Cyclopentane, Edwin L. Sibert Iii, Peter F. Bernath Jan 2022

A Local Mode Study Of Ring Puckering Effects In The Infrared Spectra Of Cyclopentane, Edwin L. Sibert Iii, Peter F. Bernath

Chemistry & Biochemistry Faculty Publications

We report and interpret recently recorded high-resolution infrared spectra for the fundamentals of the CH2 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 (D5h) of the vibrational basis sets leads to simple vibration/pseudorotation Hamiltonians whose solutions …


Retrieval Of Carbon Dioxide Vertical Profiles From Solar Occultation Observations And Associated Error Budgets For Ace-Fts And Cass-Fts, C. E. Sioris, C. D. Boone, R. Nassar, K. J. Sutton, I. E. Gordon, K. A. Walker, P. F. Bernath Jan 2014

Retrieval Of Carbon Dioxide Vertical Profiles From Solar Occultation Observations And Associated Error Budgets For Ace-Fts And Cass-Fts, C. E. Sioris, C. D. Boone, R. Nassar, K. J. Sutton, I. E. Gordon, K. A. Walker, P. F. Bernath

Chemistry & Biochemistry Faculty Publications

An algorithm is developed to retrieve the vertical profile of carbon dioxide in the 5 to 25 km altitude range using mid-infrared solar occultation spectra from the main instrument of the ACE (Atmospheric Chemistry Experiment) mission, namely the Fourier transform spectrometer (FTS). The main challenge is to find an atmospheric phenomenon which can be used for accurate tangent height determination in the lower atmosphere, where the tangent heights (THs) calculated from geometric and timing information are not of sufficient accuracy. Error budgets for the retrieval of CO2 from ACE-FTS and the FTS on a potential follow-on mission named CASS …