Velocity distributions and diffusion tensor modified by broadband irradiation

Abstract

We evaluate the velocity distributions for both atomic states for optically active two-state atoms immersed in a buffer gas and irradiated with a broadband radiation field. Collisions with buffer-gas particles are assumed to be completely thermalizing and the collision rates are state dependent. Furthermore, we calculate the drift velocity and the anisotropic diffusion tensor as functions of various parameters of the system. In particular we give explicit results for the case of a spectral distribution in the shape of a step function. The results determine the basic equations for light-induced drift and diffusive pulling.