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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.

International audience; In heavy ion collisions at low energy (E/A < 10–15 MeV/nucleon) the N/Z ratio in the entrance channel is closely related to the isospin degree of freedom and can influence the reaction mechanisms and consequently the production of the fragments in the exit channel. We analyse the fragment production cross sections in the reactions$^{86}$Kr +$^{48}$Ca and$^{78}$Kr +$^{40}$Ca , at the laboratory energy of 10 MeV/nucleon. The experiment was conducted at the INFN Laboratori Nazionali del Sud in Catania, by using the $ 4\pi$ detector CHIMERA. For the two reactions, elastic scattering measurements are performed to extract the normalization factor used to evaluate the absolute cross sections. Velocity and energy spectra, mass and charge distributions, as well as dynamic features of reaction products, are studied. The study of the characteristics of mass and charge distributions, energy and velocity spectra of the reaction products shows mainly a relaxed component, related to fusion reaction followed by evaporation or binary decay. Nevertheless signals ascribable to a non equilibrated component are present. Structure effects are evident in the staggered shape of emitted fragments cross sections and are more pronounced in the neutron poor system. The analysis highlights clear differences for the two systems in the contributions arising from different reaction mechanisms. Besides, a study of the overall influence from the entrance channel energy is performed. Comparisons to DNS (DiNuclear System) and GEMINI++ models are reported. The data analysis indicates a slightly higher fusion-evaporation cross section and a strongly pronounced probability of fission-like processes for the neutron poor system with respect to the neutron rich one. The neutron enrichment seems thus to limit the formation of the composite system and to inhibit the fission decay channel.

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.

International audience; The light charged particle evaporation from the compound nucleus and from the complex fragments in the reactions$^{32}$S+$^{100}$Mo,$^{121}$Sb+$^{27}$Al,$^{40}$Ar+$^{164}$Dy, and$^{40}$Ar+$^{nat}$ Ag is studied within the dinuclear system model. The possibility to distinguish the reaction products from different reaction mechanisms is discussed.

International audience; In heavy-ion collisions at low energy, the decay mode of the compound nucleus formed in fusion reactions can be strongly influenced by the isospin degree of freedom, strictly connected to the isotopic ratio N/Z of the system. The competition among the disintegration modes of 118,134Ba∗ produced in 78,86Kr+40,48Ca reactions at 10 A MeV has been studied in the framework of the ISODEC experiment, and experimental data have been compared with the prediction of GEMINI++ and DiNuclear System (DNS) models.

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.

This is an Open Access article distributed under the terms of the Creative Commons Attribution License 4.0, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.ISBN: 978-88-7438-101-2; International audience; Within the dinuclear system model fusion-fission reactions 78Kr+40Ca and 86Kr+48Ca is investigated. The charge distributionsof the decay products are predicted at bombarding energy 10 MeV/nucleon. The competition is treated between complete fusionfollowed by the decay of compound nucleus and quasifission channels. The possible explanation of the odd-even staggering in the yield of thefinal reaction products at high excitation energies is discussed.

International audience; The possibilities of production of the doubly magic nucleus 100Snin complete fusion and quasifission reactions with stable and radioactiveion beams are investigated within a dinuclear system model. Theexcitation functions for production of the exotic nuclei 100−103Sn viacluster emission channels are predicted for future experiments.

In the framework of dinuclear system (DNS) model we calculate the light charged particle (LCP) multiplicities produced in fusion and quasifission reactions and their kinetic energy spectra. Calculations indicate that with increasing bombarding energy the ratio of LCP multiplicity from fragments M FF to corresponding LCP multiplicity from compound nucleus (CN) M CN strongly increases.

Decay modes of excited nuclei are studied in 78,82 Kr + 40 Ca reactions at 5.5 MeV/nucleon by means of light-charged particles measured in coincidence with intermediate mass fragments and fission-like fragments. Inclusive cross-section distributions of fragments with charge 3 ≤ Z ≤ 28 are bell-shaped and a strong oddeven-staggering (o-e-s) is observed for 3 ≤ Z ≤ 12. Coincidence measurements suggest that the light partners in very asymmetric fission are emitted at excitation energies below the particle emission thresholds. Data were confronted to the predictions of statistical models describing the decay of compound nuclei by emission of light particles and fragments. Comparison with models suggests that the o-e-s of the light-fragment yields is mainly due to the successive steps of compound nucleus disintegration.

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 influence of entrance channel isospin, charge asymmetry, and bombarding energy on the competition between the complete fusion followed by the decay of compound nucleus and quasifission channels is treated within the dinuclear system model. The charge (mass) distributions of the products in the reactions ${}^{16,22}$O+${}^{27}$Al, ${}^{92,78}$Kr+${}^{40}$Ca, ${}^{86}$Kr${+}^{48}$Ca, ${}^{122}$Sn+${}^{12}$C, ${}^{32}$S+${}^{100}$Mo, ${}^{48}$Ca+${}^{144,154}$Sm, and ${}^{20,28}$Ne+${}^{181}$Ta are calculated at bombarding energies above the Coulomb barrier. The evolution of charge distribution of the complex fragments from the excited rotating nucleus ${}^{134}$Xe with increasing angular momentum and excitation energy is demonstrated.

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