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Infrared absorption spectra of gaseous HD. IV. Analysis of the collision-induced fundamental band of the pure gas

Journal Article · · J. Chem. Phys.; (United States)
DOI:https://doi.org/10.1063/1.433906· OSTI ID:7112412

Studies of the infrared absorption spectra of the HD fundamental band in the pure gas, reported for the room temperature in Paper I of this series, have now been extended to temperatures 77 and 196 K. The spectra of the band were recorded for a number of gas densities up to 50 amagat. In addition to the usual collision-induced broad features of the infrared fundamental band of a symmetric diatomic gas, these spectra at 77 and 196 K show the dipole-allowed sharp R/sub 1/(0) and R/sub 1/(1) transitions owing to the individual molecules. Derived binary absorption coefficients of the collision-induced band are (1.15 +- 0.06) x 10/sup -35/ and (1.71 +- 0.07) x 10/sup -35/ cm/sup 6/ s/sup -1/ at 77 and 196 K, respectively. An analysis of the absorption profiles of the band at 77 and 196 K and those of the band at 298 K reported in Paper I was carried out, and the characteristic half-width parameters delta/sub d/ and delta/sub c/ of the short-range overlap-induced transitions and delta/sub q/ (and delta/sub q prime/) of the long-range quadrupole-induced transitions are derived. The contributions of the overlap- and quadrupolar-interactions to the absorption intensity of the band are separated by the method of profile analysis. The magnitude parameter lambda and the range rho of the overlap-induced dipole moment for the HD--HD collision pairs are determined by obtaining the best fit of the calculated overlap part of the binary absorption coefficient as a function of temperature to the experimental values. Derived overlap parameters are lambda=5.60 x 10/sup -3/, rho=0.25 A, and ..mu.. (sigma) (the overlap-induced dipole moment at the Lennard--Jones intermolecular diameter sigma) =3.1 x 10/sup -2/ ea/sub 0/.

Research Organization:
Department of Physics, Memorial University of Newfoundland, St. John's, Newfoundland, Canada A1C 5S7
OSTI ID:
7112412
Journal Information:
J. Chem. Phys.; (United States), Journal Name: J. Chem. Phys.; (United States) Vol. 66:12; ISSN JCPSA
Country of Publication:
United States
Language:
English