Empirical and theoretical calculations of L-subshell Coster-Kronig transitions in atoms with 28 ≤ Z ≤ 98

This work presents a comprehensive analytical investigation of Coster–Kronig transition probabilities f , f , f , F , and F for elements with atomic numbers ≤ Z ≤ . Experimental data from our previous studies were systematically compiled and employed to construct smooth empirical trends by polynomial interpolation so as to represent the variation of these transitions across the different elements. In parallel, new theoretical values were calculated for selected elements using the Multiconfiguration Dirac–Fock (MCDF) method, incorporating relativistic effects. When compared with available theoretical and experimental data the results show good agreement, especially for medium and heavy elements. These new results provide reliable reference data for modeling L-shell vacancy decay processes and support a range of applications in atomic physics, X-ray spectroscopy, and radiation interaction studies.