Experimental Determination of L Shell Fluorescence Yields and Coster–Kronig Transition Probabilities of Platinum

An accurate database of atomic fundamental parameters (FPs) is crucial for quantitative material analysis based on x‐ray fluorescence (XRF). Given the wide range of applications and the limited reliability of existing experimental FPs for the L subshells of platinum, we determined its partial L fluorescence yields and Coster–Kronig transition probabilities using transmission and reference‐free XRF measurements. The determined values are ω L 3 = 0.289 (11), ω L 2 = 0.326 (13), ω L 1 = 0.0820 (34), f 23 = 0.130 (39), f 12 = 0.158 (40), and f 13 = 0.37 (18). These results show good agreement with certain tabulated values, and systematic trends are observed across atomic number Z for ω L 3 , ω L 2 , f 12 , and f 13 . The relative standard uncertainties for ω L 2 , ω L 1 , and f 12 have been significantly reduced compared to previous experimental studies. The use of tunable monochromatic photon beams and high‐precision instrumentation allowed us to establish a reliable uncertainty budget for the determined results.