Quasidynamic propagation in diabatic landscapes for low energy nuclear fission

Abstract

Successive procedure for evaluating diabatic contributions to the static energy surface is proposed, based on solving collective equation of motion simultaneously with equations for the single-particle occupation probabilities. The method is applied so far to 235U(nth, f) in terms of schematic asymmetric two center shell model. Shifts in fragment mass asymmetry due to diabatic dynamics are observed.PACS: 25.85-w; 21.60-n

Future of nuclear fission theory

“…At those intersections the probability to switch orbitals would be computed by the Landau-Zener formula (Wittig 2005). This viewpoint has been pursued further in the later literature, especially in the context of MM models (Schütte and Wilets 1978, Nörenberg 1983, Matev and Slavov 1991 but the challenges of implementing a microscopic theory has prevented the actual calculation of macroscopic parameters such as friction coefficients.…”

“…Thus, we may now make theoretical predictions of the balance between inertial and dissipative dynamics that can be used as inputs to more macroscopic models such as the ones solved with the Langevin equation. The steps to carry out this programme could follow the strategy of the dissipative diabatic dynamics (DDD) approach (Nörenberg 1983, Nörenberg 1984, Berdichevsky et al 1989, Matev and Slavov 1991, Mirea 2014, Mirea 2016. This would involve the construction of diabatic PES, computing the interaction matrix elements between the configurations that cross each other, and obtaining information about the time-dependence of the motion along the path.…”

“…It should be noted that TDHF models for high-energy fission are too diabatic, as the absence of pairing leads to artificial fission hindrance (Goddard et al 2015). The inclusion of pairing by allowing occupation number evolution solves this hindrance problem (Matev and Slavov 1991, Tanimura et al 2015; see also section 3.10.…”

Future of Nuclear Fission Theory

“…Thus, we may now make theoretical predictions of the balance between inertial and dissipative dynamics that can be used as inputs to more macroscopic models such as the ones solved with the Langevin equation. The steps to carry out this program could follow the strategy of the dissipative diabatic dynamics (DDD) approach (Nörenberg, 1983(Nörenberg, , 1984Berdichevsky et al, 1989;Matev and Slavov, 1991;Mirea, 2014Mirea, , 2016. This would involve the construction of diabatic PES, computing the interaction matrix elements between the configurations that cross each other, and obtaining information about the time-dependence of the motion along the path.…”