SPECTRAL ANOMALIES OF LIGHT-INDUCED DRIFT OF RUBIDIUM AND LITHIUM UNDER MONOCHROMATIC EXCITATION

The anomalous light-induced drift (LID) of atoms caused by a velocity dependence of collision frequencies has been investigated in the frame of the theory without adjustable parameters. Our results open the pos sibility of experimental probing of models of interatomic potentials. The extension of the strong-collision model to the case of velocity-de pendent collision rates, is the basis of our approach. The obtained mo del describes the anomalous LID both in the case of arbitrary mass rat io of absorbing- and buffer-gas particles and in the case of arbitrary ratio of the homogeneous and Doppler widths. In particular, we applie d our model to describe the anomalous LID in alkali-noble-gas mixtures (Rb-Kr and Li-Ne systems). Qualitatively another anomaly of the LID v elocity was also found in the low-pressure region. As pointed out, the optical pumping effect and the hyperfine structure of the ground elec tronic state, but not the velocity dependence of the collision rates, are the sources of this new anomaly.