Dissipative forces and multistage processes in heavy ion collisions

The problem of inclusion of friction force of nuclear matter responsible for energy and angular momentum dissipation of relative motion of colliding nuclei into collision quantum theory is considered. Transition amplitudes are calculated both for multistage inelastic excitation proesses and for transfer processes accompanying by energy dissipation in the inlet channel (quasidirect processes). The analytical expression for the experimentally measured differential cross section of the process is obtained. It is shown that friction forces can lead to substantial predominance of the stripping process contribution as compared with the breakup process into the excited particles formation in the inlet channel in ion collision with heavy nuclei. The expression derived for differential cross section can be used for obtaining spectroscopic functions of highly excited nuclei states