title: Temperature- and pressure-dependent study of 35Cl NQR frequency and spin lattice relaxation time in 2,3-dichloroanisole.
abstract: The temperature and pressure dependence of (35)Cl NQR frequency and spin lattice relaxation time (T(1)) were investigated in 2,3-dichloroanisole. Two NQR signals were observed throughout the temperature and pressure range studied. T(1) 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 CH(3) group. T(1) versus temperature data were analyzed on the basis of Woessner and Gutowsky model, and the activation energy for the reorientation of the CH(3) 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.
authors.affiliation: Department of Physics, Bangalore University, Bangalore-560056, India. ramukls@yahoo.com
authors.forename: L
authors.initials: L
authors.lastname: Ramu
authors.forename: K P
authors.initials: KP
authors.lastname: Ramesh
authors.forename: D
authors.initials: D
authors.lastname: Ramananda
authors.forename: R
authors.initials: R
authors.lastname: Chandramani
mesh_terms: D000840:Anisoles / Q000737:chemistry*; D002713:Chlorine; D009682:Magnetic Resonance Spectroscopy / Q000592:standards; D011312:Pressure; D012015:Reference Standards; D013696:Temperature
chemical_list: D000840:Anisoles; D002713:Chlorine