  Closed expressions for the Green function and amplitude of the scalar
particle scattering in the external gravitational field $g_{\mu\nu}(x)$ are
found in the form of functional integrals. It is shown that, as compared with
the scattering on the vector potential, the tensor character of the
gravitational field leads to a more rapid increase of the cross section with
increasing energy. Discrete energy levels of particles are obtained in the
Newton potential.
