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Title: Matrix isolation infrared spectroscopic and theoretical study of 1,1,1-trifluoro-2-chloroethane (HCFC-133a)

The molecular structure and infrared spectrum of the atmospheric pollutant 1,1,1-trifluoro-2-chloroethane (HCFC-133a; CF{sub 3}CH{sub 2}Cl) in the ground electronic state were characterized experimentally and theoretically. Excited state calculations (at the CASSCF, MR-CISD, and MR-CISD+Q levels) have also been performed in the range up to ∼9.8 eV. The theoretical calculations show the existence of one (staggered) conformer, which has been identified spectroscopically for the monomeric compound isolated in cryogenic (∼10 K) argon and xenon matrices. The observed infrared spectra of the matrix-isolated HCFC-133a were interpreted with the aid of MP2/aug-cc-pVTZ calculations and normal coordinate analysis, which allowed a detailed assignment of the observed spectra to be carried out, including identification of bands due to different isotopologues ({sup 35}Cl and {sup 37}Cl containing molecules). The calculated energies of the several excited states along with the values of oscillator strengths and previous results obtained for CFCs and HCFCs suggest that the previously reported photolyses of the title compound at 147 and 123.6 nm [T. Ichimura, A. W. Kirk, and E. Tschuikow-Roux, J. Phys. Chem. 81, 1153 (1977)] are likely to be initiated in the n-4s and n-4p Rydberg states, respectively.
Authors:
; ;  [1] ;  [2] ; ;  [3]
  1. Departamento de Química, Universidade Federal da Paraíba, 58059-900 João Pessoa-PB (Brazil)
  2. Departamento de Química, Universidade Estadual da Paraíba, 58429-500 Campina Grande-PB (Brazil)
  3. Departamento de Química, Universidade de Coimbra, 3004-535 Coimbra (Portugal)
Publication Date:
OSTI Identifier:
22251367
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Chemical Physics; Journal Volume: 139; Journal Issue: 20; Other Information: (c) 2013 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; CHLORINE 35; CHLORINE 37; INFRARED SPECTRA; MATRIX ISOLATION; MOLECULAR STRUCTURE; OSCILLATOR STRENGTHS; POLLUTANTS; RYDBERG STATES; SPECTROSCOPY; XENON