This study provides a database of 7903 experimental L-shell X-ray fluorescence cross-section values, including partial, total, and subshell transition cross sections for elements with atomic numbers in the range 31≤Z≤92. These data were obtained by photoionization measurements performed at excitation energies ranging from 4 keV to 123.6 keV and were compiled from 126 papers published between 1985 and 2025. Weighted average values were calculated for each element and transition. In addition, the ratios between experimental and weighted average values, together with weighted mean ratios, combined standard deviation, and the average z-scores were used to evaluate the overall reliability of the published experimental measurements, data dispersion, and internal consistency. The resulting database provides a much-needed comprehensive reference source to support X-ray fluorescence research, atomic, molecular and radiations physics studies, along with related practical applications that require defensible values and associated uncertainties for L-shell fluorescence cross sections.
Comparative analysis on total cross sections is performed on several leading quantum-mechanical perturbative boundary-proper theories for single charge-exchange in four-body heavy particle collisions at intermediate and high impact energies. These are the boundary-corrected first Born (CB1-4B), the four-body continuum distorted wave (CDW-4B), the boundary-corrected continuum intermediate state (BCIS-4B) and the Born distorted wave (BDW-4B) methods. The present applications are made for direct and inverse processes for which these methods employ different analytical calculations and algorithms in the corresponding computer programs. To cross-validate such varieties, the principle of detailed balance is advantageously explored to correlate the total cross sections for direct and inverse collisions. In this way, it is shown numerically that detailed balance is fully satisfied for all the four methods. To accurately describe the examined encounters, the appropriate solutions of four-body quantum-mechanical problems with four dynamically active particles (two nuclei and two electrons) are required. The first-order methods (e.g. CB1-4B) are based on one-step pathways with only the projectile–target interactions. The second-order methods (e.g. CDW-4B, BCIS-4B, BDW-4B) describe two-step processes via target ionization followed by capture of the emitted electron. The ejected electron must have a high momentum in order to be captured by a fast projectile. This ionization-capture mechanism is a quantum-mechanical analogue of the classical Thomas double scattering. It is suggested that detailed balance should beneficially be employed as a consistency check also in other distorted-wave computations (direct vs. inverse processes, with the underlying juxtaposition: prior vs. post transition amplitudes and static vs. dynamic correlations).
We updated the atomic energy tables of Visscher and Dyall to reflect contemporary developments in nuclear physics and chemistry. To achieve this objective more conveniently, a newly developed, highly accurate Gaussian basis set (single-family exponent even-tempered 80 (SFXE80)) was adopted instead of numerical basis functions in the Dirac–Hartree–Fock calculations. After confirming sufficient accuracy through a comparative assessment with numerical basis functions, the SFXE80 basis set was used to construct the updated total energy tables. Nuclear charge distributions were modeled using the homogeneous charged sphere, Gaussian, two-parameter Fermi (2pF), and augmented Gaussian 12 (AG12) models. A novel semi-analytical formulation was developed to evaluate the nuclear attraction integrals with Gaussian basis functions using the 2pF nuclear charge distribution. Furthermore, the AG12 parameters were fitted to align with the 2pF model definitions used in this study.
In this paper we present a large-scale sensitivity study of reaction rates in the s and i process. We identified all rates with the highest absolute sensitivity on the production of each element. In addition, the effect of the radioactive decays on the abundances during the time between the end of the nucleosynthesis and the actual observation is considered.
