Experimental and computational study of HF+Xe scattering

Journal Article · Sun Jul 01 00:00:00 EDT 1979 · J. Chem. Phys.; (United States)

DOI:https://doi.org/10.1063/1.438095· OSTI ID:6214494

Becker, C H; Tiedemann, P W; Valentini, J J; Lee, Y T; Walker, R B

Crossed molecular beam experiments have been performed measuring angular distributions I (theta) of HF(/sup 1/..sigma../sup +/) scattered off Xe(/sup 1/S/sub 0/) at collision energies of 0.044 and 0.153 eV. The I (theta) show rainbow and supernumerary rainbow structure, with diffractive oscillations just being resolved in the low energy data. A spherically symmetric potential V/sub 0/(R) is fit to the data with well depth and minimum position 0.016 eV and 3.77 A. Using this V/sub 0/(R), four model potential surfaces V (R,..gamma..) are constructed and scattering calculations are performed employing the centrifugal sudden approximation. The calculations treat HF as a rigid rotor and use a collision energy of 0.044 eV. The calculations emphasize the role of the initial rotational state as well as the effect of the type and degree of anisotropy of V (R,..gamma..) upon total and state-to-state center-of-mass differential cross sections. In particular, it is found that when V (R,..gamma..) is strongly attractive for one limited range of atom--diatom orientations, the elastically scattered rainbow is shifted to larger angles compared to the rainbow from V/sub 0/(R) scattering: if the initial rotational state j/sub in/=0. For j/sub in/=1 and 2 the V (R,..gamma..) scattering tends to resemble that for V/sub 0/(R). Because the j/sub in/ distribution in the HF beam is not well characterized, and because it is shown that very similar total differential cross sections at one energy can be generated from qualitatively different V (R,..gamma..) with similar V/sub 0/(R), even for the same j/sub in/, conclusions about the HF--Xe anisotropy of V (R,..gamma..) from I (theta) are precluded. However, the extracted V/sub 0/(R) is thought to be realistic based on the consistency of fits to the two I (theta) at significantly different collision energies and the likelihood of a relatively high rotational temperature of the HF beam due to heating of the nozzle source.

• Research Organization: Materials and Molecular Research Division, Lawrence Berkeley Laboratory and Department of Chemistry, University of California, Berkeley, California 94720
• OSTI ID: 6214494
• Journal Information: J. Chem. Phys.; (United States), Journal Name: J. Chem. Phys.; (United States) Vol. 71:1; ISSN JCPSA
• Country of Publication: United States
• Language: English

Related Subjects

640304* -- Atomic
Molecular & Chemical Physics-- Collision Phenomena
74 ATOMIC AND MOLECULAR PHYSICS
ANGULAR DISTRIBUTION
ATOM COLLISIONS
ATOM-MOLECULE COLLISIONS
BEAMS
COLLISIONS
DISTRIBUTION
ELASTIC SCATTERING
ELEMENTS
HYDROFLUORIC ACID
HYDROGEN COMPOUNDS
INORGANIC ACIDS
INTERMOLECULAR FORCES
MOLECULAR BEAMS
MOLECULE COLLISIONS
NONMETALS
RARE GASES
SCATTERING
XENON