TRANSPORT-COEFFICIENTS FOR SHAPE DEGREES IN TERMS OF CASSINI OVALOIDS

Previous computations of the potential landscape with the shapes param etrized in terms of Cassini ovaloids are extended to collective dynami cs at finite excitations. Taking fission as the most demanding example of large scale collective motion, transport coefficients are evaluate d along a fission path. We concentrate on those for average motion, na mely, stiffness C, friction gamma, and inertia M. Their expressions ar e formulated within a locally harmonic approximation and with the help of linear response theory, Different approximations are examined and comparisons are made with both previous studies, which involved differ ent descriptions of single-particle dynamics, and macroscopic models. Special attention is paid to an appropriate definition of the deformat ion of the nuclear density and its relation to that of the single-part icle potential. Far temperatures above 3 MeV the inertia agrees with t hat of in irrotational flow to less than a factor of 2, but shows larg er deviations below, in particular in its dependence on the shape. Als o, friction exhibits large fluctuations along the fission path for sma ll excitations. They get smoothed out above 3-4 MeV where gamma attain s values in the range of the wall formula. For T greater than or equal to 2 MeV the inverse relaxation time beta=gamma/M turns out to be rat her insensitive to the shape and increases with T.