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Title: The infrared spectrum of the He–C{sub 2}D{sub 2} complex

Spectra of the helium-acetylene complex are elusive because this weakly bound system lies close to the free rotor limit. Previously, limited assignments of He–C{sub 2}D{sub 2} transitions in the R(0) region of the ν{sub 3} fundamental band (≈2440 cm{sup −1}) were published. Here, new He–C{sub 2}D{sub 2} infrared spectra of this band are obtained using a tunable optical parametric oscillator laser source to probe a pulsed supersonic slit jet expansion from a cooled nozzle, and the analysis is extended to the weaker and more difficult P(1) and R(1) regions. A term value approach is used to obtain a consistent set of “experimental” energy levels. These are compared directly with calculations using two recently reported ab initio intermolecular potential energy surfaces, which exhibit small but significant differences. Rovibrational energies for the He–C{sub 2}H{sub 2} complex are also calculated using both surfaces. A Coriolis model, useful for predicting spectral intensities, is used to interpret the energy level patterns, and a comparison with the isoelectronic complex He–CO is made.
Authors:
 [1] ;  [2] ;  [3] ;  [4]
  1. Department of Physics and Astronomy, University of Calgary, 2500 University Drive North West, Calgary, Alberta T2N 1N4 (Canada)
  2. National Research Council of Canada, Ottawa, Ontario K1A 0R6 (Canada)
  3. Department of Physical Chemistry, and Center for Research in Biological Chemistry and Molecular Materials (CIQUS), University of Santiago de Compostela, E-15782 Santiago de Compostela (Spain)
  4. Department of Chemistry and Biochemistry, Utah State University, Logan, Utah 84322-0300 (United States)
Publication Date:
OSTI Identifier:
22416184
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Chemical Physics; Journal Volume: 142; Journal Issue: 8; Other Information: (c) 2015 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; ACETYLENE; CARBON MONOXIDE; COMPARATIVE EVALUATIONS; ENERGY LEVELS; HELIUM COMPLEXES; INFRARED SPECTRA; INTERMOLECULAR FORCES; LASER RADIATION; PARAMETRIC OSCILLATORS; POTENTIAL ENERGY; PROBES; SURFACES