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The yields of products of multinucleon transfer reaction $^{48}\mathrm{Ca}+^{248}\mathrm{Cm}$ at energy ${E}_{\mathrm{lab}}=5.63\phantom{\rule{0.28em}{0ex}}\mathrm{MeV}/\mathrm{nucleon}$ around the corresponding Coulomb barrier are analyzed within the dinuclear system model. The calculation results are compared with the experimental data obtained with the separator for heavy-ion reaction products SHIP at GSI. The model describes rather well the experimental production cross sections of isotopes with $Ng126$ but deviates from the experimental cross sections for the very neutron-deficient Pa and U isotopes.

The influence of the entrance channel charge (mass) asymmetry and bombarding energy on the characteristics of spin distribution of reaction products is studied within the dinuclear system model. The thermal excitation of rotational bearing modes is considered in the dinuclear system. For future experiments with the reactions 40Ca + 82Kr, 12C + 122Sn, and 48Ca + 86Kr at energies near and above the Coulomb barrier, the intrinsic rotation of the resulting fragments is predicted.

The new approach to the interpretation of the process of spontaneous fission of heavy nuclei is suggested. It is based on nuclear physics data which are obtained in heavy ion collisions. The process of spontaneous fission consists of three sequential stages: clusterization of the valent nucleons of a heavy nucleus into a light nucleus-cluster, which leads to the formation of a dinuclear system; evolution of the dinuclear system which proceeds by nucleon transfer from the heavy to light nucleus and decay of the dinuclear system from the equilibrium configuration into two fragments.

The formation and evolution of dinuclear systems in quasifission reactions are investigated. The process of formation of reaction products is analyzed based on the concept of a dinuclear system. Isotopic trends of cross sections of production of superheavy nuclei in quasifission reactions are discussed. The yields of new neutron-rich isotopes of nuclei with Z = 64–80 in quasifission reactions are predicted. The mechanism of production of complex fragments in complete fusion and quasifission reactions is analyzed.

The production cross sections of neutron-deficient isotopes $^{108--110}\mathrm{Xe}$ and $^{112--114}\mathrm{Ba}$ in the complete fusion reactions $^{58,56}\mathrm{Ni}+^{54}\mathrm{Fe}$ and $^{58,56}\mathrm{Ni}+^{58}\mathrm{Ni}$ with stable and radioactive beams are studied with the dinuclear system model. The calculated results are compared with the available experimental data. The optimal beam energies and corresponding maximum production cross sections of new isotopes $^{108}\mathrm{Xe}$ and $^{112}\mathrm{Ba}$ are predicted.

Within the dinuclear system model the charge, mass, and isotopic distributions of the products in the reactions $^{78}\mathrm{Kr}+^{40}\mathrm{Ca}$ and $^{86}\mathrm{Kr}+^{48}\mathrm{Ca}$ are predicted at bombarding energy 10 MeV/nucleon. The heavy-ion phase-space exploration code is applied to take into consideration the pre-equilibrium emission of light particles. The competition is treated between complete fusion followed by the decay of compound nucleus and quasifission channels. The possible explanation of the odd-even staggering in the yield of the final reaction products at high excitation energies is discussed.

A survey of theoretical and experimental investigations of the process involving the emission of heavy clusters from excited nuclear systems produced in heavy-ion reactions at low collision energies is given. The dinuclear system (DNS) model for calculating cross sections for the formation of heavy clusters in complete-fusion and quasifission reactions is described in detail. The results of respective calculations are compared with relevant experimental data and with the results obtained on the basis of different models. The role of the angular momentum, the asymmetry of the entrance channel, the N/Z ratio, and the excitation energy in the formation of final reaction products is studied within the proposed approach. A method is developed for calculating cross sections for evaporation-residue formation. This method takes into account both channels of light-particle emission and channels of heavy-cluster emission. The possibility for the formation of Rn, Fr, and Ra isotopes in channels of heavy-cluster emission from the excited compound nucleus of Pu is demonstrated for the first time. The calculated cross sections and isotopic distributions for residual nuclei arising upon the emission of heavy clusters from an excited compound nucleus of Pu are in good agreement with experimental data. The model developed in the present study permits finding optimum experimental conditions (projectile-target combination and bombarding energy) for studying processes involving the emission of specific complex fragments.

Decay modes of excited nuclei are investigated in {sup 78,82}Kr+{sup 40}Ca reactions at 5.5 MeV/nucleon. Charged products were measured by means of the 4{pi} INDRA array. Kinetic-energy spectra and angular distributions of fragments with atomic number 3 {le} Z {le} 28 indicate a high degree of relaxation and are compatible with a fissionlike phenomenon. Persistence of structure effects is evidenced from elemental cross sections ({sigma}{sub Z}) as well as a strong odd-even staggering (o-e-s) of the light-fragment yields. The magnitude of the staggering does not significantly depend on the neutron content of the emitting system. Fragment-particle coincidences suggest that the light partners in very asymmetric fission are emitted either cold or at excitation energies below the particle emission thresholds. The evaporation residue cross section of the {sup 78}Kr+{sup 40}Ca reaction is slightly higher than the one measured in the {sup 82}Kr+{sup 40}Ca reaction. The fissionlike component is larger by {approx}25% for the reaction having the lowest neutron-to-proton ratio. These experimental features are confronted to the predictions of theoretical models. The Hauser-Feshbach approach including the emission of fragments up to Z = 14 in their ground states as well as excited states does not account for the main features of {sigma}{submore » Z}. For both reactions, the transition-state formalism reasonably reproduces the Z distribution of the fragments with charge 12 {le} Z {le} 28. However, this model strongly overestimates the light-fragment cross sections and does not explain the o-e-s of the yields for 6 {le} Z {le} 10. The shape of the whole Z distribution and the o-e-s of the light-fragment yields are satisfactorily reproduced within the dinuclear system framework which treats the competition among evaporation, fusion-fission, and quasifission processes. The model suggests that heavy fragments come mainly from quasifission while light fragments are predominantly populated by fusion. An underestimation of the cross sections for 16 {le} Z {le} 22 could signal a mechanism in addition to the capture process.« less

The influence of angular momentum on the competition between complete fusion followed by the decay of compound nucleus and quasifission channels is treated within the dinuclear system model. The charge distributions of the products in the reactions $^{28}\mathrm{Si}$$+$$^{96}\mathrm{Zr}$, $^{4}\mathrm{He}$$+$$^{130}\mathrm{Te}$, and $^{40}\mathrm{Ca}$$+$$^{82}\mathrm{Kr}$ are predicted at bombarding energies above the Coulomb barrier. The results of calculations for the reactions $^{93}\mathrm{Nb}$$+$$^{9}\mathrm{Be}$,$^{12}\mathrm{C}$,$^{27}\mathrm{Al}$; $^{84}\mathrm{Kr}$$+$$^{27}\mathrm{Al}$; $^{86}\mathrm{Kr}$$+$$^{63}\mathrm{Cu}$; $^{139}\mathrm{La}$$+$$^{12}\mathrm{C}$,$^{27}\mathrm{Al}$; and $^{45}\mathrm{Sc}$$+$$^{65}\mathrm{Cu}$ are compared with the available experimental data.

The spectral, dissipative, and statistical properties of the damped quantum oscillator are studied in the case of non-Markovian and nonstationary system-heat bath coupling. The dissipation of collective energy is shown to be slowed down, and the decoherence rate and entropy grow with modulation frequency.

The formation of excited compound nucleus (CN) and its statistical decay is investigated within the dinuclear system (DNS) model.The initial DNS is formed in the entrance channel when the projectile is captured by a target, and then the evolution of DNS in mass asymmetry coordinate leads to formation of the hot CN. The emission barriers for complex fragments were calculated within the DNS model by using the double folding procedure for the interaction potential. It is shown that cross sections for complex fragment emission become larger when excited CN is more neutron deficient. This approach gives also an opportunity to calculate the new neutron deficient isotopes production cross sections and can be applied to describe the hot fission of heavy systems.The model was tested by comparison of calculated results with experimental data

The influence of an external magnetic field on the non-Markovian dynamics of an open two-dimensional quantum system is investigated. The fluctuations of collective coordinate and momentum and transport coefficients are studied for a charged harmonic oscillator linearly coupled to a neutral bosonic heat bath. It is shown that the dissipation of collective energy slows down with increasing strength of the external magnetic field. The role of magnetic field in the diffusion processes is illustrated by several examples.

The analytical expressions for the time-dependent friction and diffusion coefficients are presented for the case of coupling in coordinates between the collective subsystem and a squeezed heat bath. The effects of initial phase-sensitive and -insensitive correlations of the heat bath on the diffusion coefficients, fluctuations, and decoherence are studied. The interplay between friction and decoherence is discussed.

The mechanism of production of evaporation residues in low energy fusion reactions is investigated within the dinuclear system model. The model predictions for the production cross sections of exotic nuclei are compared with the available experimental data. The possibilities of production of doubly magic nucleus 100 Sn via particle evaporation channels and 12 C emission channel in the reactions 72;74;76 Kr+ 40 Ca, 72;74;76 Kr+ 40 Ar and 72;74;76 Kr+ 32 S are investigated at bombarding energies 4 6 MeV/nucleon. The reactions with radioactive ions are of great interest for experimental and theoretical studies. The experiments with neutron-rich and neutron-deficient nuclei open a new doors for the investigation of the properties of nuclear matter un- der extreme N=Z-ratio and can lead to production of still unknown isotopes. There were several experimental attempts to produce