Ionic interactions in molten complex chlorides from vibrational dephasing

In this article we present the first quantitative estimates of the spectros copically active part of the interaction potential in molten complex chlori des based on dephasing studies. We have selected the molten salt systems co ntaining quasispherical complex MCl4-2 anions (M=Mn+2 and Zn+2) and perform ed the study of their nu (1)(A(1)) isotropic Raman line profiles as a funct ion of the temperature and concentration. We have analyzed the form of the time correlation function of vibrational dephasing and determined the type of modulation events, which cause the line broadening processes in these sy stems; these are found to be purely discrete Markovian. Within the formalis m of the purely discrete Markovian modulation, we have made a judgement abo ut spectroscopically active interactions in these systems. Interionic poten tial in complex chlorides is dominated by the attraction forces, which depe nd on the interparticle distance r as r(-4), and by repulsion of the r(-7)- type. (C) 2001 American Institute of Physics.