9-13 July 2012
The Lattice Dynamics of Mercuric Chloride
Presented by Dr. Jonathan KEARTLAND on 13 Jul 2012 from 11:00 to 11:20
Type: Oral Presentation
Track: Track A - Division for Condensed Matter Physics and Materials
Measurements of the nuclear spin-lattice relaxation time (<i>T</i><sub>1</sub>) of the Cl nuclei in a high purity sample of the molecular solid mercuric chloride (HgCl<sub>2</sub>) have been made over the temperature range 4 K - 500 K using pure nuclear quadrupole resonance. Spin-lattice relaxation in this material appears to be dominated by lattice vibrations and librations over the entire temperature range investigated. Analysis of the data using available spin-lattice relaxation models has allowed us to estimate the Debye temperature and to follow changes in the lattice dynamics as a function of temperature. At high temperatures (> 350 K) deviations from the expected quadratic relationship between the spin-lattice relaxation rate and temperature have been noted. Further analysis shows this is a thermally activated process. Related changes in the resonance lineshape in this temperature range provide strong evidence of a double potential well in which the nuclei move between two energetically similar positions.