We first prove semiclassical resolvent estimates for the Schrödinger operator in
,
,
with real-valued potentials which are Hölder with respect to the radial
variable. Then we extend these resolvent estimates to exterior domains in
,
, and
real-valued potentials which are Hölder with respect to the space variable. As an
application, we obtain the rate of the decay of the local energy of the solutions to the
wave equation with a refraction index which may be Hölder, Lipschitz or just
.