A. I. Sanzhur

Isoscalar giant dipole resonance and nuclear matter incompressibility coefficient

We present results of microscopic calculations of the strength function, S(E), and alpha-particle excitation cross sections sigma(E) for the isoscalar giant dipole resonance (ISGDR). An accurate and a general method to eliminate the contributions of spurious state mixing is presented and used in the calculations. Our results provide a resolution to the long standing problem that the nuclear matter incompressibility coefficient, K, deduced from sigma(E) data for the ISGDR is significantly smaller than that deduced from data for the isoscalar giant monopole resonance (ISGMR).

Nuclear level density with fixed exciton number

An expression for the nuclear level density has been obtained for fixed number of particlesp and holesh taking into account the energy dependence of the single-particle state density for a gas model of noninteracting particles. The applicability of the equidistant spacing model (g=const.) is analyzed for the casesp≃h andp− h≫1. The possibility of factorization of the angular momentum dependence is studied provided g≠const. A semi-classical expression for the dependence of the single-particle density on angular momentum projection has been obtained without specifying the nuclear potential. Them-dependence ofg(ɛ, m) is shown to be close to a Gaussian for the infinite square well potential. A simple expression which takes into account the effect of the Pauli exclusion principle is proposed for the angular momentum dispersion of the level density distribution.

Fixed exciton number level density for a finite potential well

We present a calculation of the nuclear level densityωph(E) for a fixed number of particlesp and holesh, taking into account the energy dependence of the singleparticle level densityg(ɛ). We demonstrate the significant effects of the finite depth of the potential well (continuum effect) and the finite surface thickness of the nucleus on the value ofωph(E).

Phase transitions in asymmetric nuclear matter

We discuss the structure of the three-dimension pressure-temperature-asymmetry surface of equilibrium of the asymmetric nuclear matter, studied within the thermal Thomas-Fermi approximation, and present results for the caloric curves in the case of isobaric heating. We pay special attention to the difference of the asymmetry parameter between the boiling sheet and that of the condensation sheet of the surface of equilibrium and show that hot nuclear matter can exist (in a bound state) at higher asymmetry than the cold one. We demonstrate the presence of the plateau region in caloric curves at the isobaric heating of the asymmetric nuclear matter and show that the shape of the caloric curve depends on the pressure and is sensitive to the value of the asymmetry parameter. We also point out that the experimental value of the plateau temperature T≈5–7 MeV corresponds to the pressure P=10−2 MeV/fm3 at the isobaric boiling.

Relaxation time of nonequilibrium nuclear system

In the framework of the exciton model an expression for the relaxation time of nonequilibrium nuclear system has been obtained. It was demonstrated that one can determine this time by the values of transition rates at equilibrium.