Damping of vibrational excitations in glasses at terahertz frequency: The case of 3-methylpentane
KAUST DepartmentBiological and Environmental Sciences and Engineering (BESE) Division
Physical Sciences and Engineering (PSE) Division
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AbstractWe report a compared analysis of inelastic X ray scattering (IXS) and of low frequency Raman data of glassy 3-methylpentane. The IXS spectra have been analysed allowing for the existence of two distinct excitations at each scattering wavevector obtaining a consistent interpretation of the spectra. In particular, this procedure allows us to interpret the linewidth of the modes in terms of a simple model which relates them to the width of the first sharp diffraction peak in the static structure factor. In this model, the width of the modes arises from the blurring of the dispersion curves which increases approaching the boundary of the first pseudo-Brillouin zone. The position of the boson peak contribution to the density of vibrational states derived from the Raman scattering measurements is in agreement with the interpretation of the two excitations in terms of a longitudinal mode and a transverse mode, the latter being a result of the mixed character of the transverse modes away from the center of the pseudo-Brillouin zone.
CitationBaldi G, Benassi P, Fontana A, Giugni A, Monaco G, et al. (2017) Damping of vibrational excitations in glasses at terahertz frequency: The case of 3-methylpentane. The Journal of Chemical Physics 147: 164501. Available: http://dx.doi.org/10.1063/1.4998696.
SponsorsWe gratefully acknowledge the prolific debates and stimulating discussions with the late Professor M. Sampoli who has brought to our attention the interesting phenomenology of this glass-forming liquid.
JournalThe Journal of Chemical Physics