Subshell Occupation Numbers Research Articles

Study of light tellurium isotopes along the yrast line

The projected shell model is employed to study the light tellurium isotopes along the yrast line. The results are obtained for yrast bands, moment of inertia and B(E2) transition probabilities. Besides this, the systematics of E21+,E41+/E21+ and B(E2;21+⟶01+) and BCS subshell occupation numbers are investigated in light 106−112Te isotopes. The results on moment of inertia predict the occurrence of phenomenon of backbending around the band crosssing region due to the alignment of a pair of neutrons in the neutron 1h11/2 subshell. The maximum collectivity is observed at N = 60 due to the large neutron-proton (n-p) interaction between spin-orbit partner (SOP) [(g9/2)π, (g7/2)ν] orbits and occupation of down slopping components of νh11/2 subshell.

Study of the structure of yrast bands of neutron-rich 114-124Pd isotopes

The projected shell model calculations have been carried out in the neutron-rich 114-124Pd isotopic mass chain. The results have been obtained for the deformation systematics of \(E(2^{+}_{1})\) and \(E(4^{+}_{1})/E({2}^{+}_{1})\) values, BCS subshell occupation numbers, yrast spectra, backbending phenomena, B(E2) transition probabilities and g-factors in these nuclei. The observed systematics of \(E(2^{+}_{1})\) values and \(R_{42}\) ratios in the 114-124Pd isotopic mass chain indicate that there is a decrease of collectivity as the neutron number increases from 68 to 78. The occurrence of backbending in these nuclei as well as the changes in the calculated B(E2) transition probabilities and g -factors predict that there are changes in the structure of yrast bands in these nuclei. These changes occur at the spin where there is crossing of g-band by 2-qp bands. The predicted backbendings and predicted values of B(E2)s and g-factors in some of the isotopes need to be confirmed experimentally.

Study of yrast bands and electromagnetic properties in neutron-rich 114–128Cd isotopes

The projected shell model framework has been employed to carry out a systematic study on the deformation systematics of E(21+) and E(41+)/E(21+) values, BCS subshell occupation numbers, yrast spectra, backbending phenomena and electromagnetic quantities in 114–128Cd isotopes. Present calculations reproduce the observed systematics of the E(21+), R42 and B(E2;2+→0+) values for 114–128Cd isotopic mass chain and give the evidence that deformation increases as one moves from 114Cd to 118Cd, thereafter it decreases up to 126Cd. This in turn confirms 118Cd to be the most deformed nucleus in this set of isotopic mass chain. The emergence of backbending, decrease in B(E2) values and change in g-factors in all these isotopes are intimately related to the crossing of g-band by 2-qp bands.

Cranked Nilsson-Strutinsky vs the spherical shell model: A comparative study ofpf-shell nuclei

A comparative study is performed of a deformed mean field theory, represented by the cranked Nilsson-Strutinsky (CNS) model, and the spherical shell model. Energy spectra, occupation numbers, B(E2)-values, and spectroscopic quadrupole moments in the light pf shell nuclei are calculated in the two models and compared. The result is also compared to available experimental data which are generally well described by the shell model. Although the Nilsson-Strutinsky calculation does not include pairing, both the subshell occupation numbers and quadrupole properties are found to be rather similar in the two models. It is also shown that ``unpaired'' shell model calculations produce very similar energies as the CNS at all spins. The role of the pairing energy in the description of backbending and signature splitting in odd-mass nuclei is also discussed.

Thermal Hartree-Fock theory in opacity calculation

Hartree-Fock (HF) theory of fluctuations is used in the DCA-UTA opacity calculations. The configuration probabilities in the DCA (Detailed Configuration Accounting) approach are obtained using the variances resulting from this fluctuation theory. The HF theory of fluctuations takes into account the correlations in the subshell occupation numbers. Systematic derivation of the bound-bound absorption formula in the case of the UTA (Unresolved Transition Array) approach is presented. Comparison between the calculated and experimental opacities is shown in the case of two measured transmission spectra.

Application of Hartree-Fock theory of fluctuations to opacity calculation

The Hartree-Fock theory of fluctuations leading to simple formulae for configuration probabilities is used in a Detailed Configuration Accounting calculation of opacity in the case of an iron plasma. A direct Detailed Term Accounting method is also applied. The correlations of subshell occupation numbers, which are accounted for in the HF theory, show small effect on the theoretical spectrum corresponding to conditions of a recent measurement.

Atomic Thomas‐Fermi theory and electron subshell filling

AbstractIn previous work on electron subshell filling, the existence condition of the integrals involved has not been taken into proper account. As a result, part of the calculated subshell occupation numbers is meaningless.In Theis' theory [9] the average number of electrons in a subshell is calculated as the difference between two integrals. With each of these integrals an existence condition is associated. Because of this, the number of electrons with angular momentum quantum number l can only be calculated for atoms of which the Z value is (much) larger than the corresponding empirical first‐appearance Z value. Thus, the range of Z for which such numbers can be calculated, is restricted considerably, especially for larger values of l.Results obtained from a normalized version of Mason's approximation [13] to the exact Thomas‐Fermi function, have been compared with a least‐squares fit of the empirical subshell occupation numbers, and these are found to be as good as one may expect from a statistical theory.A lower bound to each of the empirical first‐appearance Z values has been calculated. The results agree well with those reported in other work.

Proton and neutron occupation numbers forfp-shell nuclei

Spectroscopic factors for single-particle transfer are calculated from many-particle shell-model wave functions for 23 different transfer reactions onfp-shell nuclei. A comparison of the present theory with the available experimental data is very successful. Subshell occupation numbers of target ground states are studied in detail. Some systematic deficiencies for low seniority shell-model wave functions are revealed. In several cases the experimental information appears to be rather incomplete.