for any real and positive 's' and in the sense of semiclassical approximation
is this valid ??
$ \sum_{n}exp(-sE_{n})\sim \iint_{C}dxdpe^{-s(p^{2}+V(x))}$ valid for every 's'
here simply both the sum and integral are convergent, so in this case the approximation can be seen as the replacement of a sum by an integral.