Cascade relaxation of single K, L, M and N vacancies in atomic platinum. Ion yields and energy reemission

Cascade decays of single vacancies in K to N shells of the Pt atom are studied by construction and analysis of the decay trees. Energies of cascade-produced multivacancy configurations and decay branching ratios are calculated in Pauli–Fock approximation. The role of multiplet splitting and multiplet overlapping in calculating mean transition energies and ionic configurations branching ratios is discussed. Final cascade ion yields, spectra of cascade electrons and photons, numbers of emitted electrons and photons, and energies carried away by them are calculated. Energy acquired by the Pt atom upon photoionization is split into the following channels: a) energy stored in final cascade ions, b) energy reemitted by cascade electrons, and c) energy reemitted by cascade photons. Relative weights of these energy redistribution channels are studied. A potential of using Pt-containing agents as radiosensitizers in photon activation therapy and chemoradiation therapy of malignant tumors is discussed. Cascade-produced electrons are shown to be the main local dose depositors.