Accession Number : AD0758241

Title :   Raman Spectra of Van der Waals Complexes in Argon,

Corporate Author : TEXAS UNIV AUSTIN ELECTRONICS RESEARCH CENTER

Personal Author(s) : Morgan,Clifford Eugene ; Frommhold,L.

Report Date : 12 JAN 1973

Pagination or Media Count : 135

Abstract : The Raman spectra of high purity helium, xenon, and especially argon, were observed at a number of temperatures between the boiling points and 300K and pressures from vacuum to four atmospheres. Because of the high sensitivity of the experiment, the spectra were obtained at gas densities for which predominantly two-body collisions occurred and at gas temperatures widely different from room temperature, in contrast to previous work in this field. The scattering is completely depolarized and the ratio of the Stokes intensity to the anti-Stokes intensity is equal to a Boltzmann factor. In the spectra of argon, a continuous band structure resembling an unresolved pure rotation band was observed. The wavelength, corresponding to the peak of the band structure, shifts with temperature in agreement with the theoretical shifts for a pure rotation band of a diatomic molecule. A similar band structure was observed for xenon, but with peaks evidently so close to the Rayleigh line that only shoulders were resolved. In the case of helium, only slight scattering was observed at the lowest temperature and highest pressure. These new results do not completely agree with present theories of light scattering by noble gases. It is suggested that the light scattering is due to a metastable Van der Waals dimer or complex. (Author Modified Abstract)

Descriptors :   (*ARGON, *RAMAN SPECTROSCOPY), BAND SPECTRA, XENON, HELIUM, ATOMIC ENERGY LEVELS, ATOMIC SPECTROSCOPY, MOLECULAR ASSOCIATION

Subject Categories : Atomic and Molecular Physics and Spectroscopy

Distribution Statement : APPROVED FOR PUBLIC RELEASE