A relaxation time study of SF5reorientation in solid tetrakis (pentafluorosulfanyl) hydrazine, (SF5)2NN(SF5)2

摘要

An experimental and theoretical study of the19F relaxation in solid tetrakis (pentafluorosulfanyl) hydrazine due to the reorientation of the SF5groups has been undertaken.T1andT1rgr;have been measured from 138 to 292 K.T1is very long, reaching a maximum of 1140 s at the lowest temperature for one sample, and is determined primarily by paramagnetic impurities.T1rgr;appears to be influenced by paramagnetic impurities below 227 K and determined by the reorientation of the SF5groups above 227 K. Expressions forT1andT1rgr;have been derived for two different reorientational models. In the first model the SF5group is assumed to undergo 90deg; jumps about theC4axis; whereas, in the second model the SF5group is assumed to undergo rotational diffusion about theC4axis. TheT1rgr;measurements above 227 K have been fit to the derived expressions to obtain the correlation time for the reorientation.