Four-time rotational correlation functions
Institut für Physikalische Chemie, Johannes Gutenberg-Universität Mainz, 55099 Mainz, Germany
Accepted: 5 October 1998
A scheme to analyze four-time rotational correlation functions of any rank is developed and details for rank L=1 and 2 are given. The scheme provides a transparent way for identifying deviations from simple Markovian dynamics as observed, e.g., in complex liquids close to the glass transition. The method should be applicable to NMR and optical multiple-pulse techniques as well as to photon correlation spectroscopy. Results are given for 2H-NMR multiple-pulse data in supercooled glycerol. We identify and analyze the dynamical heterogeneity of molecular reorientation in a range of close to the glass temperature .
PACS: 05.40.+j – Fluctuation phenomena, random processes, and Brownian motion / 61.20.Lc – Time-dependent properties; relaxation / 64.70.Pf – Glass transitions
© EDP Sciences, 1998