The temperature dependence of nuclear magnetic resonance in a single crystal

Abstract

The temperature dependence of the nuclear magnetic resonance in a single crystal grown by the slow-evaporation method has been investigated by employing a Bruker FT NMR spectrometer. The three-line structure due to the quadrupole interaction was measured in three mutually perpendicular crystal planes. From the experimental data, the quadrupole coupling constant, , and asymmetry parameter, , are determined at room temperature. The principal axes of the EFG tensor are parallel to the crystallographic a-, b-, and c-axes. The largest principal axis Z is parallel to the crystallographic c-axis. In the temperature range 140 - 400 K, the nuclear quadrupole coupling constant of Li in decreases as the temperature increases. The temperature dependence of the quadrupole parameters is satisfactorily explained with a single torsional frequency of the Li - O ion by means of the simple Bayer theory.