This anthology is devoted to the theoretical and experimental study of coherent phenom- ena in quantum optics. Considerable attention is devoted to the investigation of cooperative effects in multilevel molecular and atomic systems. The theoretical analysis is based on a single approach, using the theory of groups, which makes it possible to present the results in a compact and physically elegant form. The results of a detailed experimental and theoretical investigation of the photon echo, self-induced transparency, and nutation are presented. The theory of a coherent resonant mechanism for the interaction of laser radiation with multi- atomic molecules which causes "prompt" dissociation is presented. A number of applied pos- sibilities, in particular, the control of radiation by laser light and laser isotope separation, are analyzed. v CONTENTS Coherent Physics and Its Applications. * . . * * . . * ...* * * * ...* ...1 L. A. Shelepin Superradiance Effects in Molecular Systems...* ...* . . * * * . . * ...19 * . . I. M. Lizin, T. M. Makhviladze, and L. A. Shelepin Coherence and Radiation Control in Multilevel Systems ...* * * * * * . . * * ...35 * V. P. Kudrya, T. M. Makhviladze, 1.
G. Sinitsyn, and L. A. Shelepin Difference Methods and Their Role in the Theory of Coherent Phenomena...* . . 53 V. P. Karasev and L. A. Shelepin A study of the Coherent Interaction of Pulsed Infrared Radiation with Molecular Gases. . * ...* ...* ...* * . . * ...89 ...* S. S.