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Title: Failure of rigid shell models for rotationally inelastic LiH--He collisions

Abstract

A simple rigid-body model for rotationally inelastic LiH--He collisions has been implemented. This treatment assumes impulsive collisions between a point particle and a smooth spherical shell whose center is displaced from the center of mass of the LiH molecule. For a given collision energy the radius and displacement of the shell are adjusted for a best fit to the equipotential contour at this energy on the ab initio surface of D. M. Silver (J. Chem. Phys. 72, 6445(1980)). Cross sections for transitions from the rotationless j=0 state to all possible final j' states have been computed in a classical trajectory approach and have been compared to more accurate quantum coupled-states values at E/sub col/=0.3 eV (E. F. Jendrek and M. H. Alexander, J. Chem. Phys. 72, 6452(1980)). The results from this simple model differ drastically both in magnitude and their j' dependence from those obtained in the more sophisticated treatment. While such rigid-body models have been used in the analysis of inelastic scattering experiments, the present study suggests that little physical significance can be attached to the size or shape of the rigid shell contour so obtained.

Authors:
;
Publication Date:
Research Org.:
Department of Chemistry, University of Maryland, College Park, Maryland 20742
OSTI Identifier:
5208438
Resource Type:
Journal Article
Resource Relation:
Journal Name: J. Chem. Phys.; (United States); Journal Volume: 73:3
Country of Publication:
United States
Language:
English
Subject:
74 ATOMIC AND MOLECULAR PHYSICS; HELIUM; ATOM-MOLECULE COLLISIONS; LITHIUM HYDRIDES; CROSS SECTIONS; ENERGY-LEVEL TRANSITIONS; ROTATIONAL STATES; ALKALI METAL COMPOUNDS; ATOM COLLISIONS; COLLISIONS; CRYOGENIC FLUIDS; ELEMENTS; ENERGY LEVELS; EXCITED STATES; FLUIDS; HYDRIDES; HYDROGEN COMPOUNDS; LITHIUM COMPOUNDS; MOLECULE COLLISIONS; NONMETALS; RARE GASES; 640304* - Atomic, Molecular & Chemical Physics- Collision Phenomena

Citation Formats

Alexander, M.H., and Dagdigian, P.J. Failure of rigid shell models for rotationally inelastic LiH--He collisions. United States: N. p., 1980. Web. doi:10.1063/1.440233.
Alexander, M.H., & Dagdigian, P.J. Failure of rigid shell models for rotationally inelastic LiH--He collisions. United States. doi:10.1063/1.440233.
Alexander, M.H., and Dagdigian, P.J. Fri . "Failure of rigid shell models for rotationally inelastic LiH--He collisions". United States. doi:10.1063/1.440233.
@article{osti_5208438,
title = {Failure of rigid shell models for rotationally inelastic LiH--He collisions},
author = {Alexander, M.H. and Dagdigian, P.J.},
abstractNote = {A simple rigid-body model for rotationally inelastic LiH--He collisions has been implemented. This treatment assumes impulsive collisions between a point particle and a smooth spherical shell whose center is displaced from the center of mass of the LiH molecule. For a given collision energy the radius and displacement of the shell are adjusted for a best fit to the equipotential contour at this energy on the ab initio surface of D. M. Silver (J. Chem. Phys. 72, 6445(1980)). Cross sections for transitions from the rotationless j=0 state to all possible final j' states have been computed in a classical trajectory approach and have been compared to more accurate quantum coupled-states values at E/sub col/=0.3 eV (E. F. Jendrek and M. H. Alexander, J. Chem. Phys. 72, 6452(1980)). The results from this simple model differ drastically both in magnitude and their j' dependence from those obtained in the more sophisticated treatment. While such rigid-body models have been used in the analysis of inelastic scattering experiments, the present study suggests that little physical significance can be attached to the size or shape of the rigid shell contour so obtained.},
doi = {10.1063/1.440233},
journal = {J. Chem. Phys.; (United States)},
number = ,
volume = 73:3,
place = {United States},
year = {Fri Aug 01 00:00:00 EDT 1980},
month = {Fri Aug 01 00:00:00 EDT 1980}
}