Transverse dynamics of water across the melting point: A parallel neutron and x-ray inelastic scattering study

Article

关键词: FREQUENCY PROPAGATING MODES;    LIQUID WATER;    BRILLOUIN-SCATTERING;    SUPERCOOLED WATER;    VITREOUS SILICA;    COLLECTIVE DYNAMICS;    POLYCRYSTALLINE ICE;    PHONON-DISPERSION;    SOUND-VELOCITY;    HEAVY-WATER;   

DOI  :  10.1103/PhysRevB.85.174305

来源: SCIE

【 摘 要 】

Joint inelastic neutron and x-ray scattering measurements have been performed on heavy water across the melting point. The spectra bear clear evidence of low-and high-frequency inelastic shoulders related to transverse and longitudinal modes, respectively. Upon increasing the momentum transfer, the spectral shape evolves from a viscoelastic regime, where the low-frequency mode is clearly over-damped, toward an elastic one where its propagation becomes instead allowed. The crossover between the two regimes occurs whenever both the characteristic frequency and the linewidth of the low-frequency mode match the inverse of the structural relaxation time. Furthermore, we observe that the frequency of the transverse mode undergoes a discontinuity across the melting, whose extent reduces upon increasing the exchanged momentum.

【 授权许可】

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