Fusion reactions of heavy ions are investigated by employing a simple
stochastic semi-classical model which includes the coupling between relative
motion and low frequency collective surface modes of colliding ions similarly
to the quantal coupled-channels description. The quantal effect enters into the
calculation through the initial zero-point fluctuations of the surface
vibrations. Good agreement with the result of coupled-channels calculations as
well as data is obtained for the fusion cross sections of nickel isotopes. The
internal excitations in non-fusing events as well as the fusion time are
investigated.Comment: 8 pages, 8 figures, Published in Phys. Rev.