MANY-ELECTRON, MANY-PHOTON THEORY OF NONSTATIONARY STATES

A number of physical processes, such as autoionization, predissociation, ac- or dc-field-induced ionization, multiphoton dissociation, or chemical transformations, can be formulated as problems involving a nonstationary state satisfying a time-independent complex eigenvalue Schrodinger equation (CESE). The CESE gives rise to all the conceptual and practical difficulties associated with the polyelectronic structures of excited states, as well as novel ones due to the presence of external fields and to the physical significance of the continuous spectrum. In a series of articles from this institute, it has been shown how advanced electronic structure theory and methods suitable for excited states can be integrated in a practical way into selected elements of the rigorous theory of discrete states interacting with the continuous spectrum in order to solve the CESE nonperturbatively and efficiently and compute properties such as positions and widths of inner hole or multiply excited states, multiphoton ionization rates, multichannel predissociation lifetimes, nonlinear static and frequency-dependent polarizabilities, and tunneling rates. The present article constitutes a review of the basic features of this theory and its computational methods. (C) 1994 John Wiley & Sons, Inc.