We study the time evolution of a quantum particle in a Gaussian random envi
ronment. We show that in the weak coupling limit the Wigner distribution of
the wave function converges to a solution of a linear Boltzmann equation g
lobally in time. The Boltzmann collision kernel is given by the Born approx
imation of the quantum differential scattering cross section. (C) 2000 John
Wiley & Sons, Inc.