Semiclassical theory of molecular collisions in a laser field

Journal Article · Tue Feb 01 04:00:00 EST 1977 · J. Chem. Phys.; (United States)

DOI:https://doi.org/10.1063/1.434045· OSTI ID:7236494

Yuan, J; Laing, J R; George, T F

A semiclassical theory of radiative transitions for molecular collisions in an intense laser field is developed. The resulting expressions for the S-matrix involve electronic-field potential surfaces which are constructed from field-free adiabatic surfaces and transition moments. The electronic-field surfaces, which exhibit avoided crossings due to radiative coupling, are analytically continued to complex intersection points (branch points). Transitions between two such surfaces are effected by classical trajectories propagating on one surface and passing smoothly to the other surface through a branch point. Each of the two surfaces is seen to be a branch of a quadruple-valued potential function, and the branch-point structure of this function is related to field-free nonadiabatic coupling and dynamic radiative coupling. Interference effects between these two kinds of couplings are discussed and illustrated for model potentials. Numerical results show enhanced transition probabilities for the collinear process Br(/sup 2/P/sub 3///sub 2/)+H/sub 2/(v=0)+h..omega.. ..-->..Br(/sup 2/P/sub 1///sub 2/)+H/sub 2/(v=0). Experimental investigations of laser enhanced energy transfer, interference effects, and the possible formation of long-lived complexes, which are not necessarily present in the field-free case, are suggested for a molecular beam experiment carried out in the presence of a laser beam. (AIP)

• Research Organization: Department of Chemistry, The University of Rochester, Rochester, New York 14627
• OSTI ID: 7236494
• Journal Information: J. Chem. Phys.; (United States), Journal Name: J. Chem. Phys.; (United States) Vol. 66:3; ISSN JCPSA
• Country of Publication: United States
• Language: English

Related Subjects

640301 -- Atomic
Molecular & Chemical Physics-- Beams & their Reactions
640304* -- Atomic
Molecular & Chemical Physics-- Collision Phenomena
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
74 ATOMIC AND MOLECULAR PHYSICS
BEAMS
COLLIDING BEAMS
COLLISIONS
CROSS SECTIONS
ELECTROMAGNETIC FIELDS
ELECTROMAGNETIC RADIATION
ENERGY-LEVEL TRANSITIONS
INELASTIC SCATTERING
LASER RADIATION
MATRICES
MOLECULE COLLISIONS
MOLECULE-MOLECULE COLLISIONS
RADIATIONS
S MATRIX
SCATTERING