From the coherent state path integral to a semiclassical initial value representation of the quantum mechanical propagator

We give a derivation of the semiclassical propagator of Herman and Kluk (HK) which is based on the coherent state path integral technique. Our procedure unveils how the complex root-search problem underlying the semiclassical coherent state path integral turns into a real initial value problem and provides an explanation for the advantages of the HK expression which is used frequently in molecular applications. (C) 1998 Elsevier Science B.V.