ePrints@IIScePrints@IISc Home | About | Browse | Latest Additions | Advanced Search | Contact | Help

NMR study of molecular dynamics and phase transitions in dimethyl ammonium hexabromo selenate $[NH_2(CH_3)_2]_2SeBr_6$

Murthy, BVS and Ramesh, KP and Ramakrishna, J (2000) NMR study of molecular dynamics and phase transitions in dimethyl ammonium hexabromo selenate $[NH_2(CH_3)_2]_2SeBr_6$. In: Journal of Physics and Chemistry of Solids, 61 (6). pp. 961-968.

[img] PDF
11111.pdf
Restricted to Registered users only

Download (125Kb) | Request a copy

Abstract

$^1H$ spin lattice relaxation study in the temperature range 439–77 K has been carried out in dimethyl ammonium (DMA) hexabromo selenate. A high temperature phase transition is observed as a dip in $T_1$ around 360 K, followed by a slope change a 222 K, and a discontinuous jump in $T_1$ at 154 K, which are also attributed to phase transitions. DMA diad axis motion and spin– rotation interaction are found to be the dominant mechanisms responsible for the observed $T_1$ behaviour above 222 K, while between 222 and 154 K, DMA torsional oscillations contribute significantly. Below 154 K the relaxation is governed by the methyl group dynamics. The motional effects are also reflected in the second moment variation with temperature.

Item Type: Journal Article
Additional Information: Copyright of this article belongs to Elsevier B.V.
Keywords: Molecular dynamics;Dimethyl ammonium dynamics;D. Phase transitions;D. Nuclear magnetic resonance (NMR)
Department/Centre: Division of Physical & Mathematical Sciences > Physics
Date Deposited: 08 Aug 2008
Last Modified: 19 Sep 2010 04:48
URI: http://eprints.iisc.ernet.in/id/eprint/15490

Actions (login required)

View Item View Item