Atomic Data and Nuclear Data Tables最新文献

The differential cross sections for the N(⁴S)-H(²S), N(⁴S)-H${}^{+}$ and N${}^{+}$(³P)-H(²S) elastic collisions were calculated and reported in the energy range of $10^{-4}$–3.7 hartree for the studies of transport properties of ionized gases with the Boltzmann equation.

They were verified by comparison with the integrated and momentum-transfer cross sections. The importance of appropriate grid of angles and possibility of neglecting the smallest phase shifts are discussed.

Davidson et al. has extended Seeger’s mass formula to non-zero excitation energies by introducing temperature-dependent coefficients in the liquid drop energy part of the semi-empirical mass formula, but did not consider the nuclear shape and shell effects. The semi-empirical mass formula of Davidson et al. is applicable for nuclear temperatures less than or equal to 4 MeV. The mass excess calculated using this mass formula with/without nuclear shape and shell effects does not reproduce the ground state mass excesses of the new atomic mass evaluation data AME2020 and/or FRDM(2012) with its coefficients at zero temperature. So, the coefficients of the semi-empirical mass formula with nuclear shape and shell effects are required to be tuned to reproduce the ground state mass excess of all the nuclei available in the recent atomic mass evaluation data AME2020 and/or FRDM(2012). The bulk and neutron–proton asymmetry coefficients of the semi-empirical mass formula of Davidson et al., including the nuclear shape and shell effects, have been tuned to reproduce the mass excess data for all known 9420 nuclei which include all the nuclei of AME2020 (Z $=$ 1-118 and A $=$ 1-295) and of FRDM(2012) (Z $=$ 8-136 and A $=$ 16-339, except 3456 nuclei which are also available in the AME2020 data) at zero temperature. The tuned bulk and neutron–proton asymmetry coefficients reproduce the ground state mass excess of the new atomic mass evaluation data AME2020 and/or FRDM(2012) within a difference of less than 1 MeV and can be used for the applications/investigations in the areas of physics where high energies are experienced or nuclei involved are in excited states, e.g., fusion–evaporation and fusion–fission processes in heavy-ion reactions. The mass excess calculated for the excited states of nuclei is compared with the excited state mass excess of the NUBASE2020 evaluation data and is in good agreement with it.

Excitation energies, transition parameters and lifetimes for 255 levels with $n$ $\le$ 4 configurations of B-like Xe${}^{49+}$ are calculated using the fully relativistic multiconfiguration Dirac–Hartree–Fock (MCDHF) method. Hyperfine structure constants, isotope shift and Landé $g_J$ factors are computed for the $2s^{2}2p,2s2p^2$ and $2p^3$ levels. The contribution of the Breit interaction and QED effects, mainly self-energy and vacuum polarization corrections, on these levels is also investigated. The uncertainties in the lifetimes and line strengths are computed, and transitions are classified according to the NIST accuracy nomenclature. A comparison with the previously available results is also carried out. This study provides extensive results for B-like Xe${}^{49+}$, which are useful for plasma diagnosis.

Experimental isomeric ratios of light (A $\le$ 4) particle-induced nuclear reactions were compiled for the product nuclides having metastable states with half-lives longer than 0.1 s. The experimental isomeric ratio data were taken from the EXFOR library and reviewed. When an experiment reports isomer production cross sections instead of isomeric ratios, the cross sections taken from the EXFOR library were converted to the isomeric ratios by us. During compilation, questionable data (e.g., preliminary data compiled in EXFOR in parallel with their final data, sum of isomer production cross sections larger than the total production cross sections) were excluded. As an application of the new compilation, goodness-of-fit was studied for the isomeric ratios predicted by the reaction model code TALYS-1.96. A text file and plots of the compiled isomer production cross sections and isomeric ratios are provided as supplemental materials.