Comparative study of frequency of torsional motion in crystals on the basis of X-ray thermal parameter and NQR data in chlorine compounds

\Torsional vibrations and the hindered rotational motions of the molecule or part of the molecule about definite axes in the crystal are the two types of molecular motions considered to have appreciable effect on the quadrupole interaction. From NQR temperature dependence studies, the torsional frequencies at different temperature from 300 K to 77 K were estimated by numerical methods and torsional frequency at 300 K has been considered for the comparative study. In the present paper, an attempt has been made to calculate torsional frequencies in various 35Cl compounds on the basis of X-ray thermal parameter, crystal structure data and were compared with the results derived from nuclear quadrupole resonance data using Bayer's and Brown's approximation. The torsional frequencies obtained by X-ray thermal parameter and NQR are impeccable. Previous experimental data revels that the torsional vibrations lie in the scale of 15 cm −1 to 150 cm −1 . In the present case, our study delineates the values obtained by X-ray thermal parameter for various compound falls in the range 17 cm −1 to 63 cm −1 . The present approach could be a lucid illustration of the supplementary nature of the information obtained from X-ray studies in regard to NQR studies of compounds in solid state. This study demonstrates the potential of combining X-ray and NQR techniques to provide a more comprehensive understanding of molecular dynamics in solid-state compounds.