Vibrational/rotational infinite-order sudden approximation applied to He + I/sub 2/

Journal Article · Thu May 21 04:00:00 EDT 1987 · J. Phys. Chem.; (United States)

DOI:https://doi.org/10.1021/j100295a033· OSTI ID:6400508

Pfeffer, G A

Vibrationally and rotationally elastic and inelastic collisions between He and I/sub 2/ in the total energy range of 0.044-0.5 eV are treated under the vibrational/rotational infinite-order sudden approximation (VRIOSA). In this method, one simultaneously makes the vibrational energy sudden, rotational energy sudden, and centrifugal sudden approximations and generates a completely uncoupled set of equations. The solution of these equations is discussed and the integral and differential cross sections, the integral and differential cross sections summed over final rotational states, the integral cross sections summed over final rotational and vibrational states, and a type of cross section which recently has been measured experimentally are presented and compared with vibrational close-coupled infinite-order sudden approximation results. The dependence of the accuracy of the VRIOSA upon the choice of the arbitrary vibrational quantum number parameters, n vector, is also investigated. Setting n vector equal to the final vibrational quantum number gives good results for the integral and experimental cross sections, while picking n vector equal to the average of the initial and final vibrational quantum numbers gives good results for the differential cross sections. The present comparisons involving a full three-dimensional system and quantities, such as the differential cross section, which are sensitive to the phase of the S matrix extend earlier, more limited studies and show that the VRIOSA should be considered convenient and reliable for light atom-heavy diatomic molecule collisions at total energies up to a few electronvolts.

• Research Organization: Univ. of Nebraska, Omaha
• OSTI ID: 6400508
• Journal Information: J. Phys. Chem.; (United States), Journal Name: J. Phys. Chem.; (United States) Vol. 91:11; ISSN JPCHA
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400201 -- Chemical & Physicochemical Properties
640304* -- Atomic
Molecular & Chemical Physics-- Collision Phenomena
74 ATOMIC AND MOLECULAR PHYSICS
ATOM COLLISIONS
ATOM-MOLECULE COLLISIONS
COLLISIONS
CROSS SECTIONS
DATA
DIFFERENTIAL CROSS SECTIONS
ELASTIC SCATTERING
ELEMENTS
ENERGY LEVELS
EXCITED STATES
FLUIDS
GASES
HALOGENS
HELIUM
INELASTIC SCATTERING
INFORMATION
INTEGRAL CROSS SECTIONS
IODINE
MATHEMATICAL MODELS
MATRICES
MECHANICS
MOLECULE COLLISIONS
NONMETALS
NUMERICAL DATA
QUANTUM MECHANICS
QUANTUM NUMBERS
RARE GASES
ROTATIONAL STATES
S MATRIX
SCATTERING
SUDDEN APPROXIMATION
THEORETICAL DATA
VIBRATIONAL STATES