Prof. Gerd Röpke (Rostock University)

We discuss the formation of nuclei in heavy-ion collisions, ternary fission, and the decompression of hot and dense matter in astrophysics. The freeze-out concept is compared with the use of reaction-kinetic equations. In-medium effects, particularly Pauli blocking and the Mott effect, must be considered. After freeze-out, the decay of excited states is also taken into account. The determination of Lagrange parameters that describe the nuclear matter at freeze-out is demonstrated for heavy-ion collisions, ternary fission, and the formation of heavy elements in stars. The reconstruction of these Lagrange parameters from observed distributions characterizes the conditions under which the nuclei are formed.