Eur. Phys. J. B 18, 501-505 (2000)
https://doi.org/10.1007/s100510070039

Exchange rates of dynamic heterogeneities in a glass-forming liquid

¹ MPI für Polymerforschung, Postfach 3148, 55021 Mainz, Germany
² Institut für Physikalische Chemie, Schlossplatz 4/7, 48149 Münster, Germany

Corresponding author: ^a andheuer@uni-muenster.de

Received: 10 April 2000
Revised: 21 September 2000
Published online: 15 December 2000

Abstract

Dynamic heterogeneities, i.e. the presence of molecules with different mobilities, have been established as one of the key features of the physics of supercooled liquids. Here we study in detail how the mobility of an individual molecule fluctuates with time. Our analysis is based on a time series of molecular dynamics simulations for a low molecular weight glass-former, propylene carbonate. We find that the variation of mobility with time of initially slow molecules significantly differs from that of initially fast molecules. We explicitly show the relation to the rate memory parameter which recently has been introduced to quantify the mobility fluctuations as observed via multidimensional NMR experiments. In this way qualitative agreement between simulation and experiment can be established although the time scales of simulation and NMR experiment differ by many orders of magnitude.