Configuration dependent crossed beam reactive scattering in an intense laser field

Abstract

We model the reaction between crossed beams of atoms A and diatoms BC in an intense nonresonant laser field. Cross sections are in particular determined for laser switching between a pair of one-dimensional potential curves which are free to rotate in space. The cross sections are dependent on the configuration or orientation of the laser field with respect to the initial relative velocity vector of the reactants; for computational simplicity, many of our calculations are performed for coincident field and relative velocity vectors. Contributions to the cross sections arising from interference between the phases of transition matrix elements, are highlighted by comparing with ones determined by random phase approximation. We also make comparison with the corresponding configuration averaged (and phase independent) cross section. Photon energy dependencies for the various cross sections are obtained at several field intensities and collision energies. We find that the shifting with photon and collision energy, of the range of partial waves from which a cross section draws, can dramatically affect the relationship between phase dependent and independent cross sections; the shifting modifies in particular the interference between transition elements. For a single field intensity and photon and collision energy, we also generate cross sections as a function of configuration angle. The structure of the configuration dependence is elucidated by decomposition into terms which are characterized by numbers of contributing photons.