The vacuum referred electron binding energies in the S01 and P13 states of Pb²⁺ and Tl⁺ in inorganic compounds

An overview of the spectroscopic data on Tl⁺ and Pb²⁺ in 37 and 126 different inorganic compounds, respectively, is presented. Using the metal-to-metal charge transfer and A-band transition energies, the electron binding energies in the S01 ground state and P13 excited state of Tl⁺ and Pb²⁺ were determined relative to the vacuum level. By constructing vacuum referred binding energy (VRBE) diagrams that display the energy levels of the Tl⁺ and Pb²⁺ activator ion together with that of the host compound, insight in the luminescent properties of these activated compounds are gained. The obtained VRBEs of the electron in the S01 and P13 states of Tl⁺ and Pb²⁺ are compared to those of Bi³⁺.