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Information × Registration Number 0206U009578, 0103U003634 , R & D reports Title Macroscopic collective motion in excited nuclei popup.stage_title Head Kolomietz Vladimir Mikhajlovich, Registration Date 27-12-2006 Organization Institute For Nuclear Research Of National Academy Of Sciences Of Ukraine popup.description2 The theory of non-markovian collective motion with memory effects has been developed. This theory had been applied to the study of giant multipole resonance structure and the description of nuclear fission. The dependence of the fragments kinetic energy and its dispersion on the number of nucleons have been calculated for nuclei from transuranium region. The theory of the cavitation in the nuclear Fermi-liquid has been developed. The conditions of volume instability has been found for high temperatures and low density of nucleons. It is shown that memory effects lead to characteristic oscillations of the unstable phase and to considerable dumping of its evolution. The energy spectra of nucleons emitted from the excited states of nuclei has been studied for two limit cases, that are evaporation and direct (non-statistical) emission of nucleons. The mean lifetime of the giant monopole resonances with respect to direct neutron emission has been obtained. The influence of the neutron excess on the isovector dipole response has been studied for the spherical nuclei. It has been found that the neutron excess increases the Landau damping for the giant dipole resonance and shifts the strength to the pygmi resonance region. The model of high-dumped motion which allows the estimation of the nucleus passage time through the fission barrier has been suggested. The calculated descant time exceeds considerably the well-known Kramers estimation. This allows the possibility of significant enhancement for the emission of light particles in nuclear fission. The transport coefficients of the quadrupole collective oscillations of nuclei have been calculated for low excitation energies in terms of the response function formalism and the quasiclassic theory of periodic orbits. It has been shown that the shell fluctuations of the transport coefficients are approximately proportional to the shell correction of the nucleus free energy. The detail analysis has been performed for the applicability of various models used for the dipole radiation strength functions in view of description of the photoabsorption cross sections for medium and heavy nuclei. The approaches (MLO1, GFL) which take into account the one-body as well as the two-body relaxation of the collective states in warm nuclei have been recommended for the calculation of the observable quantities in nuclear reactions. Product Description popup.authors popup.nrat_date 2020-04-02 Close