35Cl NQR Frequency and Spin Lattice Relaxation Time in 3,4‐dichlorophenol As a Function of Pressure and Temperature

The pressure dependences of 35Cl nuclear quadrupole resonance (NQR) frequency, temperature and pressure variation of spin lattice relaxation time (T1) were investigated in 3,4‐dichlorophenol. T1 was measured in the temperature range 77–300 K. Furthermore, the NQR frequency and T1 for these compounds were measured as a function of pressure up to 5 kbar at 300 K. The temperature dependence of the average torsional lifetimes of the molecules and the transition probabilities W1 and W2 for the Δm = ±1 and Δm = ±2 transitions were also obtained. A nonlinear variation of NQR frequency with pressure has been observed and the pressure coefficients were observed to be positive. A thermodynamic analysis of the data was carried out to determine the constant volume temperature coefficients of the NQR frequency.