EXACT FORM OF GREEN-FUNCTIONS FOR SEGMENTED POTENTIALS

We derive the exact Green functions for segmented potentials, i.e. for potentials of the form V(x) = Sigma(j=1)(N) V-(j)(x), where each V-(j )(x) has compact support. The expressions depend explicitly on the wav efunctions' quantum amplitudes (e.g. transmission and reflection coeff icients) for the individual V-(j)'s. We also show that the exact Green functions are in fact generalizations of the usual semiclassical form ula. Finally, the possibility of applying the method to a general pote ntial is briefly discussed.