Impulse formalism for atom-diatom collisions

Journal Article · Tue Jan 01 04:00:00 EST 1991 · Physical Review, A; (USA)

DOI:https://doi.org/10.1103/PhysRevA.43.189· OSTI ID:6153547

Sharma, R D ^[1]; Bakshi, P M ^[2]; Sindoni, J M ^[3]

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1. Optical/Infrared Technology Division, Geophysics Laboratory, Hanscom Air Force Base, Massachusetts 01731 (US)
2. Physics Department, Boston College, Chestnut Hill, Massachusetts 02167 (USA)
3. Yap Analytics, Inc., 594 Marrett Road, Lexington, Massachusetts 02173 (USA)

An exact formulation of the impulse approach (IA), or quantum-mechanical spectator model, is applied to atom-diatom collisions. Results are compared with previous work on the IA, which has always involved the peaking approximation (PA). The PA is seen to overestimate (underestimate) differential cross sections for processes involving projectile atom energy loss (gain). The internal consistency of the IA is explored by subjecting it to semidetailed balancing. For small scattering angles the IA is seen to be an inadequate theory, probably due to the neglect of double- and higher-collision terms in the multiple-collision expansion of the three-body {ital T} matrix. For large scattering angles, where the IA does appear to describe the scattering process accurately, the exact calculation is shown to give the same results as when only the energy-conserving on-the-energy-shell two-body processes are considered. An accurate approximation method is also developed for rapid computation of inelastic differential cross sections. Finally, the calculated results are compared with the experimental measurements, and the need to explore two-body potentials more complicated than the hard-core potential is pointed out.

• OSTI ID: 6153547
• Journal Information: Physical Review, A; (USA), Journal Name: Physical Review, A; (USA) Vol. 43:1; ISSN 1050-2947; ISSN PLRAA
• Country of Publication: United States
• Language: English

Related Subjects

640304* -- Atomic
Molecular & Chemical Physics-- Collision Phenomena
74 ATOMIC AND MOLECULAR PHYSICS
ATOM COLLISIONS
ATOM-MOLECULE COLLISIONS
COLLISIONS
DETAILED BALANCE PRINCIPLE
ENERGY LOSSES
IMPULSE APPROXIMATION
INVARIANCE PRINCIPLES
LOSSES
MOLECULE COLLISIONS
T INVARIANCE