133Cs and 14N NMR and ionic dynamics in solid cesium thiocyanate CsSCN

Abstract

The spin-lattice relaxation time, T 1, or 133Cs and 14N NMR in solid cesium thiocyanate, CsSCN, was measured as a function of temperature. 133Cs T 1 in the room-temperature phase (470K > T) was a minimum near 445K when measured at a low-resonance frequency of 7.95 MHz and was explained in terms of a 180° flip of the linear SCN − ion. The decrease of 133Cs T 1 with temperature in the high-temperature ionic-plastic phase (479K > T > 470K) was assigned to the slow translational diffusion of the cations and the increase of 14N T 1 to the fast overall reorientation of the SCN − ions.