Host anion effect on the energy level scheme of Sm3+ in SmOX (X=F, Cl and Br)

The energy level schemes obtained from the optical absorption and luminescence data for the Sm3+ doped oxyhalides (SmOX, X = F, Cl and Br) were simulated with a phenomenological model accounting simultaneously for the free ion interactions and the crystal field (c.f.) effect. The values of the Slater integrals (F-k) describing the electrostatic interactions increase as a function of the ionic radius of the anion from SmOF to SmOBr. The value of the host independent c.f. strength parameter S for the hexagonal SmOF matrix (580 cm(-1)) is more than 50% higher than for the tetragonal SmOCl or SmOBr. This indicates the importance of the ionic contribution to the c.f. effect.