Laser-assisted electron-argon scattering at small angles

Electron-argon scattering in the presence of a linearly polarized, low frequency laser field is studied theoretically. The scattering geometries of interest are small angles where momentum transfer is nearly perpendicular to the field, which is where the Kroll-Watson approximation has the potential to break down. The Floquet R matrix method solves the velocity gauge Schr\"odinger equation, using a larger reaction volume than previous treatments in order to carefully assess the importance of the long range polarization potential to the cross section. A comparison of the cross sections calculated with the target potential fully included inside 20 and 100 a.u. shows no appreciable differences, which demonstrates that the long range interaction can not account for the high cross sections measured in experiments.