Chlorine nuclear quadrupole resonance transition frequency in p-chloroaniline

The Nuclear Quadrupole Resonance transition frequency of Cl in p-chloroaniline has been measured as a function of temperature in the range 80–300 K. Its temperature dependence is analyzed using Bayer's theory in the quasi-harmonic approximation and including the internal modes contribution. Excellent agreement is found with Raman and IR data. Also, the importance of the internal modes is clearly shown. The N transition frequency data are analyzed, and in order to produce good agreement with previous work a simple model to account for the electric field gradient at the N nuclear site had to be proposed.