The concept of the laser came into existence more than a decade ago when ScHAWLOW and TowNES showed that the maser principle could be extended to the optical re

159 elements only between states which differ in one of the single-electron wave functions, in short, HeR induces only one-electron transitions. The matrix elem

The dynamical properties of solids have recently attracted renewed interest in connection with the increasing understanding of phase transitions and re lated ph

Includes Part 1, Number 2: Books and Pamphlets, Including Serials and Contributions to Periodicals (July - December)