Quasi elastic and inelastic neutron scattering study of vitamin C aqueous solutions

In this paper, new results obtained by quasi elastic and inelastic neutron scattering experiments performed on vitamin C ( -ascorbic acid)/H2O mixtures are reported. The data analysis of the QENS measurements, by a separation of the diffusive dynamics of hydrated -ascorbic acid from that of water, furnishes quantitative evidences of a random jump diffusion motion of vitamin C and shows that the water dynamics is strongly affected by the presence of -ascorbic acid. Concerning the INS experiment, we are able, through the behaviour of neutron spectra across the glass transition temperature (Tg≈233 K for the vitamin C/water system), to collocate the investigated system in the Angell “strong-fragile” scheme.