³⁵Cl NQR Studies of Bismuth Trichloride

Abstract

The temperature dependence of the 35 C1 nuclear quadrupole resonance (NQR) frequency and spin lattice relaxation time (Ti) are studied in crystalline BiCl 3 , in the range 40 -300 K. The positive temperature coefficient observed for one of the 35 C1 resonances is explained in terms of the strong intermolecular interactions that exist in this compound. Variation of with temperature is found to be similar at the chemically inequivalent halogen sites. Semiclassical descriptions based on torsional oscillator dynamics are found to be inadequate for explaining the spin lattice relaxation. Tj (T) data follow an AT 2 + BT 3 type behaviour, indicating that the anharmonic nature of the lattice vibrations plays a significant role in determining the temperature dependence of 7i at high temperatures.