  Considerable progress has recently been made in controling the motion of free
atomic particles by means of light pressure exerted by laser radiation. The
free fall of atoms and bouncing on a reflecting surface made from evanescent
wave formed by internal reflection of a quasiresonant laser beam at a curved
glass surface in the presence of homogeneous gravitational field has been
observed. In this paper we present the energy quantization of this system by
making use the asymptotic expansion method. It is shown that for large $n$ the
levels go like $n^{2/3}$ which may be compared with $n^2$ for the infinite
square well.
