Jahn–Teller Distortion: Magnetic Studies of Vanadium Tetrachloride

Abstract

Paramagnetic resonance of polycrystalline VCl4 diluted with TiCl4 has been observed near 9,24, and 36 GHz below 9°K. Both g values and hyperfine A tensors are axially symmetric and temperature independent with the same principal axes: g‖ = 1.920, g⊥ = 1.899, | A‖ | = 72 G, | A⊥ | = 120 G. The average g value obtained from susceptibility data is in agreement with the resonance value. The paramagnetic relaxation time T1 varies with temperature as shown by the relation T1 = 2 × 10− 9exp(25/T) sec, indicating the presence of a potential barrier approximately 18 cm− 1 in height. The results indicate a static Jahn–Teller distortion, but with large zero-point vibrations. This situation is in between Ballhausen–de Heer's ligand field and Ball-hausen–Liehr's crystal-field calculations.