Optimized Imploding Waves in the Coherent Control of Bimolecular Processes: Atom−Rotor Scattering

Abstract

Considerable work, over the past three decades, has gone into the study of atom-molecule inelastic collisions, including the development of extensive formalism and the calculation of cross sections for rotational, vibrational, and electronic excitations. All of these studies are designed to analyze the natural outcome of the inelastic scattering of atoms and molecules. By contrast, current interest lies in the ability to control the outcome of atomic and molecular processes. In particular, modern efforts in coherent control1-12 have aimed at using lasers to introduce controllable quantum interference terms into the cross sections of atomic and molecular processes. As a consequence, varying specific laser parameters induce changes in these quantum interference terms which, in turn, significantly alter the natural yields and cross sections. Both detailed1 and elementary2 reviews of this coherent control approach are available. Examining the coherent-control literature shows that the vast majority of controlled processes previously considered are unimolecular in nature, e.g., the photodissociation or photoionization of isolated molecules. Only recently have we shown3-6 that the essential principle of coherent control can be used effectively to alter cross sections for scattering processes. That is, we demonstrated that if one collides two molecules in a superposition of energetically degenerate scattering states, then the resultant scattering cross section contains controllable interference terms. For a general bimolecular collision of the type