On representative orbital angular momentun quantum numbers in the definite parity j/sub z/ CCS approximation

Journal Article · Mon Nov 15 04:00:00 EST 1976 · J. Chem. Phys.; (United States)

OSTI ID:7350780

Shimoni, Y; Kouri, D J

A detailed study of the role of representative orbital angular momentum quantum numbers l-bar (J,j) in a definite parity j/sub z/ CCS approximation (DPj/sub z/) is presented. First the DPj/sub z/ equations are derived by a procedure which establishes the validity for k/sub j/Rvery-much-greater-thanJj in place of k/sub j/Rvery-much-greater-than((J+j)/2)/sup 2/ in the original derivation of Kouri, Heil, and Shimoni. Then expressions for integral and differential cross sections within the DPj/sub z/ approximation are derived. This analysis points up the importance of choice functions l-bar (J,j), which determine the representative orbital angular momentum quantum numbers associated with given values J,j. Computations for the He+H/sub 2/ system are carried out for various choices of l-bar (J,j) and results are compared with exact close coupling (CC). Analyses of trends in the results suggest (a) the median choice l-bar=max(J,j) gives best results at the integral cross section level (if one disregards parity), (b) elastic cross sections for given j depend on the numerical value of l-bar and not on the l-bar' values occurring for other rotor states j', (c) averages of both partial and integral cross section results with respect to choice function l-bar (j,J) lead to excellent agreement with CC results, (d) by noting (b) above, an alternative average over l-bar values can be achieved by relabeling amplitudes by l-bar,j rather than J,j, (e) this last average can be made using the results obtained with a single choice function. (AIP)

• Research Organization: Departments of Chemistry and Physics, University of Houston, Houston, Texas 77004
• OSTI ID: 7350780
• Journal Information: J. Chem. Phys.; (United States), Journal Name: J. Chem. Phys.; (United States) Vol. 65:10; ISSN JCPSA
• Country of Publication: United States
• Language: English

Related Subjects

640302* -- Atomic
Molecular & Chemical Physics-- Atomic & Molecular Properties & Theory
640304 -- Atomic
Molecular & Chemical Physics-- Collision Phenomena
74 ATOMIC AND MOLECULAR PHYSICS
ANGULAR MOMENTUM
ATOM COLLISIONS
ATOM-MOLECULE COLLISIONS
COLLISIONS
CROSS SECTIONS
CRYOGENIC FLUIDS
DIFFERENTIAL CROSS SECTIONS
ELEMENTS
ENERGY LEVELS
EXCITED STATES
FLUIDS
HELIUM
HYDROGEN
INTEGRAL CROSS SECTIONS
MOLECULE COLLISIONS
NONMETALS
QUANTUM NUMBERS
RARE GASES
ROTATIONAL STATES