Quantum-mechanical treatment of Eu+3 4<i>f</i>→4<i>f</i> and 4<i>f</i>?charge-transfer-state transitions in Y2O2S and La2O2S

Abstract

The quantum-mechanical single-configurational-coordinate model is used to interpret Y2O2S:Eu+3 and La2O2S:Eu+3 7F→charge-transfer state (CTS) absorption, 5Di→5Di−1 one-step and 5D→CTS→5D two-step quenchings, and CTS→5Di feeding fractions. The preferred fit requires unequal force constants and a small downshifting of the CTS parabola with increasing temperature.