M. Hashimoto et al., PHASE-TRANSITION AND CRYSTAL DYNAMICS OF 4-BROMOBENZYL ALCOHOL, Zeitschrift fur Naturforschung. A, A journal of physical sciences, 53(6-7), 1998, pp. 436-441
For the title compound a phase transition from Phase II to Phase I (lo
w and room temperature phases, respectively) was found at ca. 217 K. T
he temperature dependence of the Br-81 NQR frequency and that of the d
ielectric constant showed anomalies at ca. 195 K that were tentatively
attributed to a higher order phase transition. A similar anomaly was
found at ca. 218 K for 4-chlorobenzyl alcohol which showed a II-I tran
sition at 236 K. The dielectric dispersion observed for both compounds
at low temperatures indicates an excitation of a molecular motion wit
h the dielectric relaxation rate of ca. 1 kHz. The temperature depende
nce of the Br-81 NQR frequencies of 2- and 3-bromobenzyl alcohol, meas
ured at T > 77 K, gave no evidence of phase transition in their crysta
ls.