In this article we present the first quantitative estimates of the spectroscopically active part of the interaction potential in molten complex chlorides based on dephasing studies. We have selected the molten salt systems containing quasispherical complex MCl4-2 anions (M=Mn+2 and Zn+2) and performed the study of their nu (1)(A(1)) isotropic Raman line profiles as a function 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 systems; these are found to be purely discrete Markovian. Within the formalism of the purely discrete Markovian modulation, we have made a judgement about spectroscopically active interactions in these systems. Interionic potential in complex chlorides is dominated by the attraction forces, which depend on the interparticle distance r as r(-4), and by repulsion of the r(-7)-type. (C) 2001 American Institute of Physics.