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Title: Analytical Morse/long-Range model potential and predicted infrared and microwave spectra for a symmetric top-atom dimer: A case study of CH{sub 3}F–He

Four-dimensional ab initio intermolecular potential energy surfaces (PESs) for CH{sub 3}F–He that explicitly incorporates dependence on the Q{sub 3} stretching normal mode of the CH{sub 3}F molecule and are parametrically dependent on the other averaged intramolecular coordinates have been calculated. Analytical three-dimensional PESs for v{sub 3}(CH{sub 3}F) = 0 and 1 are obtained by least-squares fitting the vibrationally averaged potentials to the Morse/Long-Range potential function form. With the 3D PESs, we employ Lanczos algorithm to calculate rovibrational levels of the dimer system. Following some re-assignments, the predicted transition frequencies are in good agreement with experimental microwave data for ortho-CH{sub 3}F, with the root-mean-square deviation of 0.042 cm{sup −1}. We then provide the first prediction of the infrared and microwave spectra for the para-CH{sub 3}F–He dimer. The calculated infrared band origin shifts associated with the ν{sub 3} fundamental of CH{sub 3}F are 0.039 and 0.069 cm{sup −1} for para-CH{sub 3}F–He and ortho-CH{sub 3}F–He, respectively.
Authors:
;  [1] ;  [2]
  1. Institute of Theoretical Chemistry, State Key Laboratory of Theoretical and Computational Chemistry, Jilin University, 2519 Jiefang Road, Changchun 130023 (China)
  2. Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853 (United States)
Publication Date:
OSTI Identifier:
22304516
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Chemical Physics; Journal Volume: 140; Journal Issue: 21; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; ALGORITHMS; ATOMS; DIMERS; FOUR-DIMENSIONAL CALCULATIONS; METHYL FLUORIDE; MICROWAVE RADIATION; MICROWAVE SPECTRA; MOLECULES; POTENTIAL ENERGY; THREE-DIMENSIONAL CALCULATIONS