³⁵Cl Nuclear Quadrupole Relaxation in Antimony Trichloride

Abstract

The 35C1 NQR frequency and spin-lattice relaxation time in SbCl3 have been measured between 10 K and the melting point. The relaxation at low temperatures is attributed to the Raman process. A Debye temperature of 141 K and covalencies 0.390 and 0.356 are obtained. The latter values correspond well to those obtained from the NQR frequencies. For the relaxation above 200 K two more mechanisms are considered.

121/123Sb Nuclear Quadrupole Resonance Spectroscopy: Characterization of Non-Covalent Pnictogen Bonds and NQR Crystallography

“…This well-known temperature-dependence is taken into consideration when comparing experimental (recorded here at room temperature) to calculated values. A few years later, Zemnukhova and Davidovich published two separate articles on 121/123 Sb NQR of antimony trifluoride complexes. , For SbCl 3 , several studies on the pure compound or on complexes have also been published a number of years ago. − All of these studies show a shifting of the 121/123 Sb NQR frequencies by a few MHz upon cocrystallization; however, these have never been rationalized in context of pnictogen bonding and no detailed study on the influence of the number of electron donors and their geometries relative to antimony moiety has been conducted to date. Furthermore, in these early studies, diffraction-based structures on which to base correlations of spectral data with structural features were often unavailable.…”

Model – free approach to quadrupole spin relaxation in solid 209Bi-aryl compounds

“…Relaxation models assuming Raman phonon dynamics have been discussed in the literature for different compounds. [32][33][34][35][36][37][38][39] Such models include many parameters and, even though, quite often do not lead to good agreement with the experiment. Actually, for the same reasons phonon models of electron spin relaxation for paramagnetic complexes has not gained much popularity.…”

“…Finishing, it is worth to point out that as vibrational frequencies are considerably larger than NQR frequencies, one can expect that relaxation models based on phonon models [32][33][34][35][36][37][38][39] would lead to a spectral density being almost independent of the corresponding NQR frequency (at least for single-phonon processes). In consequence the ratios between the relaxation rates associated with different NQR lines would follow the same (very similar) relationship as in the extreme narrowing case.…”