Excited State Of Ce Research Articles

Accurate electron affinity of atomic cerium and excited states of its anion**Project supported by the National Natural Science Foundation of China (Grant Nos. 91736102 and 11974199) and the National Key R&D Program of China (Grant No. 2018YFA0306504).

Electron affinities (EA) of most lanthanide elements still remain unknown owing to their relatively lower EA values and the fairly complicated electronic structures. In the present work, we report the high-resolution photoelectron spectra of atomic cerium anion Ce− using the slow electron velocity-map imaging method in combination with a cold ion trap. The electron affinity of Ce is determined to be 4840.62(21) cm−1 or 0.600160(26) eV. Moreover, several excited states of Ce− (4H9/2, 4I9/2, 2H9/2, 2G9/2, 2G7/2, 4H13/2, 2F5/2, and 4I13/2) are observed.

Scintillation and anomalous emission in elpasolite Cs 2LiLuCl 6:Ce 3+

The luminescence and scintillation properties of Cs 2LiLuCl 6:0.5%Ce 3+ are presented. Special attention is devoted to a 9.4 ns fast emission at 275 nm that can only be excited via the highest cubic field 5d e state of Ce. Contrary to Cs 3LuCl 6 and Cs 2LiYCl 6, where the same type of fast emission was observed, the emission in Cs 2LiLuCl 6 is still observed at room temperature. Assuming that the 5d e state is located inside the host conduction band (CB), we propose that the emission originates from a mixed state at or just below the bottom of the CB and ends at the 4f ground state of Ce 3+. To proof this model we studied the thermal quenching of the anomalous luminescence and performed X-ray photoelectron spectroscopy. A model for a temperature-activated energy transfer from the anomalous state to the lowest 5d t excited state of Ce 3+ explains most of the results. Besides the 275 nm emission, the material shows 5d t–4f Ce 3+ emission at 370 and 406 nm and 2 ns fast core-valence luminescence when excited with 16–22 eV photons. The scintillation properties of Cs 2LiLuCl 6:Ce are briefly discussed.

Photoacoustic spectroscopy of YAG crystals doped with Ce

The absorption, luminescence and photoacoustic spectra of YAG:Ce 3+ have been measured and analysed. Considering the photoacoustic and absorption spectra one has shown a decrease of the quantum efficiency of the Ce 3+ below 90% when luminescence is excited in the UV region. Simulation of the kinetics of nonradiative processes in the excited states of Ce 3+ and hot luminescence has been performed. The Jahn–Teller type coupling in the excited states of Ce 3+ has been evidenced.

The mixing interaction and energy transfer between the conduction band of SrS and the levels of Ce 3+

The behavior of hot-electrons is very important for thin film electroluminescence (TFEL) devices. In SrS:Ce TFEL, the electrons in excited states of Ce 3+ ions are easily to be ionized into conduction band under a high electric field, and are easily trapped by the ionized luminescent centers under a low electric field. In this paper, the dependence of ionization possibility on the field strength is studied and the emission wave forms were determined. The energy transfer process is discussed.