Densities of vibrational states and heat capacities of crystalline and amorphousH2O ice determined by neutron scattering

Abstract

The densities of vibrational states g(ν) of crystalline ice Ih and Ic, and of low-density and high-density amorphous ice, all at 15 K, have been determined by incoherent inelastic neutron scattering. The use of a self-consistent iterative procedure to correct for multiphonon and multiple scattering leads to highly accurate values. The mean absolute difference for Tg(ν) and that measured calorimetrically is 1.8%. The anharmonic component of the heat capacity at higher T is about twice as large as an earlier theoretical estimate.