Vibrational Spectra of Ternary Rare Earth Sulfides in Relation to Crystal Structures,

摘要

The role of bond length and coordination of a series of rare earth sulfides with the A2BS4stoichiometry on vibrational spectra was investigated. Far infrared and Raman spectra have been measured on compounds with A =La,Ce,Nd,Pr; B =Ba,Sr,Pb,Ca (Th3P4structure I(4bar)3d; A =Gd to Lu, B =Ba,Sr,Eu(2+) (CaFe2O4structure Pnam);and A =Ho,Er,Tm,Yb, Y; B =Zn,Mg,Cd (spinel structure Fd3m). Band frequencies shift uniformly with cell parameter and show discontinuous shifts to lower values as the coordination scheme is varied from 6-4to 8-6to 8-8.