Evidence of dynamical local scale distribution heterogeneities in CsF-AF (A = Li, Na, K and Rb) molten salts

Abstract

The local structure of molten CsF-AF (A = Li, Na, K and Rb) has been studied by high temperature Nuclear Magnetic Resonance (NMR) spectroscopy. The 19 F and 133 Cs chemical shifts have been measured as a function of the molar fraction of CsF. 19 F chemical shift varies linearly with composition while 133 Cs chemical shift presents a break around the eutectics composition. Furthermore, in molten CsF-LiF at high CsF concentration, 133 Cs chemical shift is nearly constant. The evolutions of 19 F and 133 Cs chemical shifts versus CsF-AF composition have been interpreted as a signature of dynamical local scale distribution heterogeneities.