Electronic Raman Scattering and Infrared Absorption in the Samarium Monochalcogenides

Electronic transitions between the FJ7 multiplet levels of Sm2+ have been observed optically in SmS, SmSe, SmTe, and Sm1-xYxS. In SmS, SmSe, and SmTe, the strong temperature dependence of the singlet-triplet energy is well described by the random-phase-approximation results of Wang and Cooper, allowing us to determine both the exchange and the spin-orbit interaction. However, no temperature dependence of the singlet-triplet energy is observed in metallic Sm1-xYxS. © 1975 The American Physical Society.