Molecular dynamics in a nematic liquid crystal probed by implanted muons
B. W. Lovett, S. J. Blundell, J. S. Stiessberger, F. L. Pratt, Th. Jestadt, W. Hayes, S. P. Cottrell, and I. D. Reid

We present the first muon spin rotation / relaxation study of a nematic liquid crystal (5CB). We identify 4 different positions for muonium addition to this compound by correlating the dominant peaks in the Fourier transform of the muon precession signal obtained in an applied transverse magnetic field. Experiments performed in a longitudinal field are used to probe changes in $\it individual$ molecular dynamics at the solid-nematic transition. High field avoided level crossing spectroscopy reveals four $\Delta M=0$ transitions which can be fitted using simplified models of $\it collective$ molecular dynamics appropriate to the solid, nematic and liquid phases.

© 1999 The American Physical Society.