This paper shows that by choosing suitably the general fundamental inv
ariant I=f (I-1) as a new canonical momentum, we can find the semiclas
sical propagator for any one-dimensional admissible potential, where I
is a certain function of the fundamental invariant I-1. We apply this
method to the case of quartic potential and point out few application
s of the propagator for this potential. (C) 1996 Academic Press, Inc.