Potential energy of fissionable nucleus in scission point depending from nucleon structure of formed fragments

Full text: The nucleus potential energy at scission point was calculated for 235U fission by thermal neutrons for fragments with mass numbers AL=78-86, ZL =28-36, AH = 150-158 and ZH = 56-64 at fixed values of EKL = 93.4, 98.3 and 103.1 MeV in order to compare with experimental results [1]. For additional pairs of fragments (for example, ZL=30 and ZH=62, ZL=32 and ZH=60) in the specified range of mass numbers the fixed quantity of neutrons (NL= 50 and NH = 94, NL = 49 and NH = 95, NL = 48 and NH = 96) was selected to define influence of magic numbers and parities on a fissionable nucleus potential energy. Then based on the procedure described in [2], at the fixed value EKL there was defined the total kinetic energy TKE, sizes of nuclei-fragments and their parameters of deformations. Further relative surface energy BS, Coulomb energy BC, volume energy BV and energy of their nuclear interaction Eprox were calculated. The calculation method of these energies is given in [3]. The values of the total energy emission Q have been calculated for calculation of the full energy balance under mass tables [4] for each pair of fragments. The surface, Coulomb and potential energies were calculated from their values for a nucleus ground state. The greatest energy emission and the least potential energy are observed at shaping of even-even fragments with charge density, close to compound nucleus density. For fragments with mass numbers AL = 72-80 charge density is close to compound nucleus density. The further increase of a mass number leads to magnification of charge density of light fragment (LF). Shape LF with A = 78 is close to spherical, and that of heavy fragment (HF) has major deformation, the neck is shaped for the account HF and has the minimum diameter ∼3 fm. Besides, for HF the surface friction and undersurface neutron stratum in comparison with LF starts to be incremented. Thereof, the scission point should be closer also to LF. The calculations of a potential energy surface with the account shell and pair effects show existence of several minimums, that is the most probable fission happens on several channels. Comparison with the experimental mass yields confirms these calculations. Also potential energy comparison in scission point for even-even and odd-odd fragments is spent at different values EKL, EKH and TKE. References: 1. W. Lang, H.-G. Clerc et al. //Nucl. Phys. A345, 1980, p. 34.; 2. Yu.N. Koblik, V.P. Pikul et al. // Izv. RAN, ser. phys., 2006, v. 70, n 5, p.673.; 3. W.D. Myers and K.-H. Schmidt. //Nucl. Phys. A410, 1983, p.61.; 4. G. Audi, A.H. Wapstra and C. Thibault // Nucl. Phys. A729, 2003, p. 337. (authors)