Tj. Martinez et al., MULTI-ELECTRONIC-STATE MOLECULAR-DYNAMICS - A WAVE-FUNCTION APPROACH WITH APPLICATIONS, Journal of physical chemistry, 100(19), 1996, pp. 7884-7895
An approach which allows for multi-electronic-state dynamics but which
is in the spirit of classical molecular dynamics is discussed and app
lied to both collisional (''curve crossing'') and ultrafast optical ex
citation problems. The formalism seeks to allow for the possibility of
quite different nuclear dynamics (e.g., bound vs dissociative) in the
different electronic states. The discussion begins from a wave functi
on formulation of the problem, and this enables one to retain interfer
ence effects if these are important, but the ultimate objective is to
obtain as classical-like a description as possible while taking accoun
t of the inter-electronic state coupling. The essential approximation
in the method is in the computation of these coupling terms which appe
ar as nonclassical corrections to the classical equations of motion. T
he computational results are tested against accurate quantal computati
ons, and the agreement is typically quantitative.