Data on the DC ionic conductivity for strongly structured molten halides of
divalent and trivalent metals near freezing are interpreted as mainly refl
ecting charge transport by the halogen ions. On this assumption the Nernst-
Einstein relation allows an estimate of the translational diffusion coeffic
ient D-tr of the halogen, in at least one case (molten ZnCl2) D-tr is much
smaller than the measured diffusion coefficient, pointing to substantial di
ffusion via neutral units, The values of D-tr estimated from the Nernst-Ein
stein relation are analyzed on the basis of a model involving two parameter
s, i.e. a bond-stretching frequency w and an average waiting time tau. With
the help of Raman scattering data for w, the values of are evaluated and f
ound to mostly lie in the range 0.02-0.3 ps for a vast class of materials.
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