Rotational sudden approximation at low energies

Journal Article · Mon Aug 15 04:00:00 EDT 1977 · J. Chem. Phys.; (United States)

DOI:https://doi.org/10.1063/1.435012· OSTI ID:7097775

Pfeffer, G; Secrest, D

The infinite-order sudden approximation is studied at low energies for a system with widely spaced energy levels to determine the limits of its validity. It is found that even under these extreme conditions it gives highly accurate results for cross sections summed over final rotational states. The elastic cross sections are also reasonably accurate in this approximation, though, for this worst case situation, the state to state cross sections for inelastic scattering are not even qualitatively correct for high ..delta..j transitions. The high accuracy of the cross sections summed over final rotational states commends the sudden approximation for use in reducing the complexity of carrying rotational channels in the calculation of vibrational transitions. The use of the sudden approximation in studying expansions of interaction potentials is discussed.

• Research Organization: School of Chemical Sciences, University of Illinois, Urbana, Illinois 61801
• OSTI ID: 7097775
• Journal Information: J. Chem. Phys.; (United States), Journal Name: J. Chem. Phys.; (United States) Vol. 67:4; ISSN JCPSA
• Country of Publication: United States
• Language: English

Related Subjects

640304* -- Atomic
Molecular & Chemical Physics-- Collision Phenomena
74 ATOMIC AND MOLECULAR PHYSICS
COLLISIONS
CROSS SECTIONS
ELASTIC SCATTERING
ENERGY LEVELS
ENERGY-LEVEL TRANSITIONS
EXCITED STATES
INELASTIC SCATTERING
MOLECULE COLLISIONS
ROTATIONAL STATES
SCATTERING
SUDDEN APPROXIMATION
VIBRATIONAL STATES