Table of contents

Physical models of the theory of infrared radiation transfer in molecular gases are reviewed and their usefulness in the solution of particular problems is demonstrated. Theoretical predictions are compared with experimental data. Particular attention is devoted to analytic methods capable of providing (1) clear descriptions of the physics of the phenomenon, (2) a better understanding of the dependence of the final result on the parameters of the problem, and (3) a reasonably reliable final result that is valid over a broad range of variation of the parameters of the gaseous medium. The radiation transfer process is examined both for equilibrium and nonequilibrium gaseous media. The final section deals with the analysis of certain processes occurring in the Earth's atmosphere.

This review presents the fundamental theoretical concepts concerning the photogalvanic effect (PGE)—the phenomenon of appearance of a direct current in a homogeneous medium under uniform illumination. This effect can occur in all media lacking a center of symmetry, in particular, in ferroelectrics, piezoelectrics, gyrotropic crystals, and in gases and liquid possessing natural optical activity. The starting point of a systematic microscopic theory is the asymmetry of the elementary electronic processes—their noninvariance with respect to spatial reflection. Within the framework of the theory, we study the most important mechanisms of the PGE in the regions of impurity, interband, and intraband light absorption. Possible observable manifestations of the PGE are discussed. Theoretical results are compared with experimental data.