Compound nucleus formation in reactions between massive nuclei: Fusion barrier

Abstract

The evaporation residue cross sections oER in reactions between massive nuclei have been analyzed within di8'erent models of complete fusion. The calculations in the framework of the optical model, the surface friction model, and the macroscopic dynamic model can give the results which are by few orders of magnitude different from experimental data. This takes place due to neglect of the competition between complete fusion and quasifission. A possible mechanism of compound nucleus formation in heavy-ion-induced reactions has been suggested. The analysis of the complete fusion of nuclei on the basis of dinuclear system approach has allowed one to reveal an important feature of the fusion process of massive nuclei, that is, the appearance of the fusion barrier during dinuclear system evolution to a compound nucleus. As a result, the competition between complete fusion and quasifission arises and strongly reduces the cross section of the compound nucleus formation. A model is proposed for calculation of this competition in a massive symmetric dinuclear system. This model is applied for collision energies above the Coulomb barrier. The crER values calculated in the framework of dinuclear system approach seem to be close to the experimental data. For illustration the reactions Mo+ Mo, Pd+ Pd, and Sn+ Zr have been considered. PACS number(s): 25.70.Gh, 25.70. Jj, 24.10.i

Theoretical study of the almost sequential mechanism of true ternary fission

“…In order to explore the mechanisms of the CCT process, we apply the theoretical framework of the dinuclear system (DNS) model [12][13][14][15]. In the present work, we estimate the total energy of the interacting system by calculate the sum of the binding energies of its constituents and the interaction potential energy between them.…”

Microscopic description of production cross sections including deexcitation effects

“…On the other hand, different theoretical approaches have also been developed: e.g. a dynamical model based on Langevin-type equations of motion [5][6][7][8][9][10][11][12], dinuclear system model (DNS) [13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28], and improved quantum molecular dynamics model (ImQMD) [29][30][31][32][33][34][35][36][37][38]. Although those models can describe both peripheral and damped collisions, including fusion and quasifission (QF) processes, they are to some extent empirical containing model parameters.…”

Theoretical study of the synthesis of superheavy nuclei withZ=119and 120 in heavy-ion reactions with trans-uranium targets

“…The DNS concept was proposed by Volkov in order to describe the deep inelastic transfer process [30]. This concept was later used to study the competition between complete fusion and quasi-fission and to calculate the fusion probability in fusion reactions [31][32][33]. Based on the DNS concept, several models have been developed for the study of the synthesis mechanism of SHN (see [34][35][36][37] and references therein).…”