Quantum-mechanical description of the initial stage of fusion reaction

Projectile-nucleus capture by a target nucleus at bombarding energies in the vicinity of the Coulomb barrier is treated on the basis of the reduced-density-matrix formalism. The effect of dissipation and fluctuations on the capture process is taken into account self-consistently within this model. Cross sections for evaporation-residue formation in asymmetric-fusion reactions are found by using the calculated capture probabilities averaged over all orientations of the deformed projectile or target nucleus.