Temperature- and pressure-dependent study of 35Cl NQR frequency and spin lattice relaxation time in 2,3-dichloroanisole
Article first published online: 28 JUN 2010
Copyright © 2010 John Wiley & Sons, Ltd.
Magnetic Resonance in Chemistry
Volume 48, Issue 8, pages 593–599, August 2010
How to Cite
Ramu, L., Ramesh, K. P., Ramananda, D. and Chandramani, R. (2010), Temperature- and pressure-dependent study of 35Cl NQR frequency and spin lattice relaxation time in 2,3-dichloroanisole. Magn. Reson. Chem., 48: 593–599. doi: 10.1002/mrc.2627
- Issue published online: 9 JUL 2010
- Article first published online: 28 JUN 2010
- Manuscript Accepted: 10 MAY 2010
- Manuscript Revised: 9 APR 2010
- Manuscript Received: 19 DEC 2009
- spin lattice relaxation time;
- torsional frequency;
- activation energy
The temperature and pressure dependence of 35Cl NQR frequency and spin lattice relaxation time (T1) were investigated in 2,3-dichloroanisole. Two NQR signals were observed throughout the temperature and pressure range studied. T1 were measured in the temperature range from 77 to 300 K and from atmospheric pressure to 5 kbar. Relaxation was found to be due to the torsional motion of the molecule and also reorientation of motion of the CH3 group. T1versus temperature data were analyzed on the basis of Woessner and Gutowsky model, and the activation energy for the reorientation of the CH3 group was estimated. The temperature dependence of the average torsional lifetimes of the molecules and the transition probabilities were also obtained.
NQR frequency shows a nonlinear behavior with pressure, indicating both dynamic and static effects of pressure. The pressure coefficients were observed to be positive for both the lines. A thermodynamic analysis of the data was carried out to determine the constant volume temperature coefficients of the NQR frequency. The variation of spin lattice time with pressure was very small, showing that the relaxation is mainly due to the torsional motions of the molecules. Copyright © 2010 John Wiley & Sons, Ltd.