Eur. Phys. J. E 8, 269-274 (2002)
Dynamical precursor of nematic order in a dense fluid of hard ellipsoids of revolutionTh. Theenhaus1, M.P. Allen2, M. Letz3, A. Latz4 and R. Schilling1
1 Institut für Physik, Johannes Gutenberg-Universität, Staudingerweg 7, D-55099 Mainz, Germany
2 H.H. Wills Physics Laboratory, University of Bristol, Royal Fort, Tyndall Avenue, Bristol BS8 1TL, UK
3 Schott Glas, Research and Developement, Hattenbergstr. 10, D-55014 Mainz, Germany
4 Institut für Physik, TU - Chemnitz, D-09107 Chemnitz, Germany
(Received 19 September 2001 and Received in final form 19 March 2002)
We investigate hard ellipsoids of revolution in a parameter regime where no long range nematic order is present but already finite-size domains are formed which show orientational order. Domain formation leads to a substantial slowing down of a collective rotational mode which separates well from the usual microscopic frequency regime. A dynamic coupling of this particular mode into all other modes provides a general mechanism which explains an excess peak in spectra of molecular fluids. Using molecular dynamics simulation on up to 4096 particles and on solving the molecular mode coupling equation we investigate dynamic properties of the peak and prove its orientational origin.
64.70.Pf - Glass transitions.
61.30.-v - Liquid crystals.
61.25.Em - Molecular liquids.
61.20.Lc - Time-dependent properties; relaxation.
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag 2002