https://doi.org/10.1140/epja/i2016-16308-6
Regular Article - Theoretical Physics
Dissipation of the tilting degree of freedom in heavy-ion-induced fission from four-dimensional Langevin dynamics
1
Omsk State Technical University, Mira prospekt 11, 644050, Omsk, Russia
2
Omsk State University, Mira prospekt 55-A, 644077, Omsk, Russia
* e-mail: nadtoch77@gmail.com
Received:
20
June
2016
Accepted:
8
September
2016
Published online:
12
October
2016
A stochastic approach based on four-dimensional Langevin fission dynamics is applied to the calculation of a wide set of experimental observables of excited compound nuclei from 199Pb to 248Cf formed in reactions induced by heavy ions. In the model under investigation, the tilting degree of freedom (K coordinate) representing the projection of the total angular momentum onto the symmetry axis of the nucleus is taken into account in addition to three collective shape coordinates introduced on the basis of 
parametrization. The evolution of the K coordinate is described by means of the Langevin equation in the overdamped regime. The friction tensor for the shape collective coordinates is calculated under the assumption of the modified version of the one-body dissipation mechanism, where the reduction coefficient ks of the contribution from the “wall” formula is introduced. The calculations are performed both for the constant values of the coefficient 
and for the coordinate-dependent reduction coefficient 
which is found on the basis of the “chaos-weighted wall formula”. Different possibilities of the deformation-dependent dissipation coefficient 
for the K coordinate are investigated. The presented results demonstrate that an impact of the and 
parameters on the calculated observable fission characteristics can be selectively probed. It was found that it is possible to describe the experimental data consistently with the deformation-dependent 
coefficient for shapes featuring a neck, which predicts quite small values of 
(MeV zs)-1/2 and constant 
-0.4 (MeV zs)-1/2 for compact shapes featuring no neck.
© SIF, Springer-Verlag Berlin Heidelberg, 2016
