One-body dissipation and fluctuation in heavy ion collisions

In classical trajectory calculations we employ the one-body window-friction to couple the relative motion of two heavy ions to the internal degrees of freedom. The conservative potential between the two ions consists of a liquid drop and a proximity part. The fluctuation of the mass number which goes with the dissipation is treated on the same footing, namely as an exchange of independent particles through the window between the nuclei. Comparison with recent data shows how much of the energy damping can be attributed to the one-body exchange mechanism. (author)