Mode coupling analysis of the dynamical structure factor in supercooled liquid Na0.5Li0.5PO3

Abstract The dynamical structure factor of supercooled Na 0.5 Li 0.5 PO 3 ( T g =515 K, T m =749 K) has been obtained by time-of-flight neutron scattering between room temperature and 773 K, just above the melting temperature. The temperature and wave number dependences of the measured spectra in the whole supercooled liquid range are shown to be well described by the solutions of a schematic mode coupling theory model. In particular, the crossover between vibrational excitations and fast relaxation processes above the susceptibility minimum is reproduced by the calculated spectra. This analysis leads then to the identification of a crossover temperature around 620 K in this non-fragile glass-forming liquid.