Variation of transport coefficients for average fission dynamics with temperature and shape

We study slow collective motion at finite thermal excitations on the basis of linear response theory applied to the locally harmonic approximation. The transport coefficients for average motion, friction γ, inertia M and the local stiffness C are computed along a fission path of ²²⁴Th within a quasi-static picture. The inverse relaxation time β = γ/M and the effective damping rate η = γ/(2√M|C|) are found to increase with temperature, but do not change much with the collective variable. The values found for η and β as well as their behavior with temperature are in accord with experimental findings.