Scattering of low-energy electrons by helium in a CO2 laser field

The scattering of low-energy electrons by helium in the presence of a CO2 laser field is studied using the R-matrix Floquet theory. Two target states are retained in the calculations, the S-1 ground state and a P-1(o) pseudostate optimized to describe the polarizability of the target. Differential cross sections for elastic scattering with net absorption/emission of up to two photons are calculated for collision energies between 1 eV and 8 eV and over a range of intensities from 10(7) W cm(-2) up to 10(8) W cm(-2). Various geometries are considered, including those in which the incident electron beam is not parallel to the laser polarization axis. The results are compared with those of Wallbank and Holmes (2001 Can. J. Phys. 79 1237), and are found to be several orders of magnitude smaller.