The R-matrix Calculations of Orientation and Coulomb Phase Effects in Electron–Molecule (Re-)Collisions

Abstract

Electron recollision in strong laser fields is usually studied with oriented molecules. This introduces orientation effects into the recollision problem which are generally not present in usual treatments of electron–molecule collisions. In addition this collision occurs with a molecular ion which means that the dominant electron– molecule interaction is the long-range Coulomb potential, which competes asymptotically with the strong laser field. Different workers have performed treatments varying between the complete inclusion of all asymptotic Coulomb effects to their complete neglect. Three possible treatments of the Coulomb problem are explored using H₂ and CO₂ as prototypical systems. Calculations based on R-matrix studies of the (re-)collision, which neglect the effects of the laser field, show that inclusion of the complete Coulomb interaction leads not only to the well-known singularity problems for forward scattering but also leads to the washing out of much of the detailed, angular structure in the differential cross section of the oriented molecules.