Vibrational origin of the fast relaxation processes in molecular glass-formers

Abstract

We study the interaction of the relaxation processes with the density fluctuations by molecular dynamics simulation of a flexible molecule model for o-terphenyl (oTP) in the liquid and supercooled phases. We find evidence, besides the structural relaxation, of a secondary vibrational relaxation whose characteristic time, few ps, is slightly temperature dependent. This i) confirms the result by Monaco et al. [Phys. Rev, E 62, 7595 (2000)] of the vibrational nature of the fast relaxation observed in Brillouin Light Scattering (BLS) experiments in oTP; and ii) poses a caveat on the interpretation of the BLS spectra of molecular systems in terms of a purely center of mass dynamics.

RevTeX, 5 pages, 4 eps figures

References in corpus (4)

• Molecular dynamics simulation of the fragile glass former ortho-terphenyl: a flexible molecule model. II. Collective dynamics
• Calcium Rubidium Nitrate: Mode-Coupling $\beta$ Scaling without Factorization
• Molecular dynamics simulation study of the high frequency sound waves in the fragile glass former ortho-terphenyl
• Orientational and induced contributions to the depolarized Rayleigh spectra of liquid and supercooled ortho-terphenyl

Cited by in corpus (2)

• Density fluctuations in the intermediate glass-former glycerol: a Brillouin light scattering study
• Unexpected Effect of Internal Degrees of Freedom on Transverse Phonons in Supercooled Liquids