Abstract
A wide frequency range and high-resolution light scattering study on the molecular fragile glass former m-tricresyl phosphate was performed. The depolarized spectra were considered as consisting of a quasielastic central line, the transverse acoustic Brillouin component (not discussed here) and the boson peak (BP). The central line width follows very closely the values known from a nuclear magnetic resonance experiment, which measured the molecular reorientation, that is the α process. The BP was considered to result at least partly from density fluctuation. We apply a hydrodynamic description to its temperature dependence, where the parameters are known from a longitudinal acoustic Brillouin scattering experiment. Thus one can successfully describe the BP as well as the region between the central line and the BP. including the considerable change in spectral shape. The relative weights of α and β processes show a temperature dependence as is often found in mode-coupling theory. The width parameter for the β process shows only a slight temperature dependence and differs between the Brillouin and BP descriptions by a factor of only two to three.