TRANSLATIONAL AND REORIENTATIONAL MOTION IN SUPERCOOLED ORTHO-TERPHENYL - A MOLECULAR-DYNAMICS STUDY

Molecular-dynamics simulations are used to determine the reorientation al correlation functions C-1(t) and C-2(t) and the self-intermediate s cattering function F-cm(8)(q, t) for a model potential that mimics ort ho-terphenyl. We find that the different correlation functions fulfill the time-temperature superposition principle in the slow relaxation r egime (alpha-relaxation). For shorter times (beta-relaxation), we fit the correlation functions to the universal prediction of the mode-coup ling theory and find agreement over about 1-2 decades in time.