Kα transition probabilities for platinum and uranium ions for possible X-ray biomedical applications1This article is part of a Special Issue on the 10th International Colloquium on Atomic Spectra and Oscillator Strengths for Astrophysical and Laboratory Plasmas.

Abstract

Platinum compounds, such as cisplatin and other high-Z materials, are increasingly common in biomedical applications. The absorption and emission of high-energy X-rays can occur via the 1s–2p Kα transitions in ions of heavy elements involving deep inner-shells. Oscillator strengths (f), line strengths (S), and radiative decay rates (A), for the 1s–2p transitions for the nine ionic states from hydrogen-like to fluorine-like, are presented for platinum and uranium. For platinum ions the Kα transitions are found to be in the hard X-ray region, 64–71 keV (0.18–0.17 Å), and for uranium ions they are in the range 94–105 keV (0.12–0.13 Å). Since the number of electrons in each ionic state of the element is different, the number of Kα transitions varies considerably. While there are two 1s–2p transitions (1s 2S1/2–2p [Formula: see text]) in H-like ions, there are 2, 6, 2, 14, 35, 35, and 14 transitions in He-like, Li-like, Be-like, B-like, C-like, N-like, and O-like ions, respectively, for a total of 112 Kα transitions for each element. These include both types of electric dipole (E1) allowed transitions, same-spin multiplicity and intercombination. The former dipole allowed transitions are in general strong; their radiative decay rates are of the order of A ∼ 1016 s–1. However, there are also many weaker transitions. We demonstrate the importance of these Kα transitions, as they appear as resonances in photo-ionization, which is relevant to the enhanced production of Auger electrons for possible radiation diagnostics and therapy.