Exact solution of the one- and three-dimensional quantum kinetic equationswith velocity-dependent collision rates: Comparative analysis

The interaction of a plane monochromatic traveling wave with two-level part icles suffering collisions with buffer-gas particles is considered. Collisi on rates are assumed to be velocity dependent. The collision integral is ob tained on the basis of the strong-collision model, generalized to the case of velocity-dependent collision rates (the so-called ''kangaroo" model). We obtained the exact analytical solution of the problem for arbitrary intens ity of radiation, arbitrary ratio of homogeneous and Doppler widths of the absorption line, and arbitrary mass ratio between absorbing- and buffer-gas particles. The obtained analytical solutions of the quantum kinetic equati ons allowed us to analyze the spectral shape of the strong-field absorption line as well as the probe-field absorption line (the nonlinear part of the work done by the probe field) and the frequency dependence of the light-in duced drift (LID) velocity. A comprehensive comparative analysis for the th ree- and one-dimensional versions of the model is given, On the basis of th is analysis, we reach the conclusion that the one-dimensional quantum kinet ic equation has quite a wide range of application. We also reveal the condi tions for the strongest manifestation of the velocity dependence of the col lision rates, which affects most strongly the anomalous LID. [S1050-2947(99 ) 02904-2].