Reorientation and Angular Momentum Correlation Times in Fluorobenzenehyphen;d5in the Liquid State

摘要

The NMR spinhyphen;lattice relaxation times of deuterium and fluorine have been measured in fluorobenzenehyphen;d5over the temperature range from 30 to 309deg;C and pressures from 1 to 2000 bar. Quadrupolar interactions represent the sole relaxation mechanism for deuterium. The spinhyphen;rotation interactions provide the dominant relaxation mechanism for fluorine but small corrections for intrahyphen; and interdipolar, and anisotropy of chemical shift contributions were carried out. Since the2D quadrupole coupling constant is known and the19F spinhyphen;rotation interaction tensor was determined by molecular beam measurements, the experimental2D and19FT1data allowed us to calculate the angular position correlation time, tgr;thgr;, and the angular momentum correlation time, tgr;J, respectively. The relationship of tgr;thgr; and tgr;Jover the range of temperatures and pressures provides useful information about the mechanism of molecular reorientation in liquid fluorobenzene. The experimental data indicate that at lower temperatureslpar;le; 100deg;Crpar;the rotational diffusion theory describes well the reorientation and that the Hubbard's relation between tgr;thgr; and tgr;Jholds. At temperatures near to critical temperature the experimental results can be interpreted in terms of the extendedJhyphen;diffusion model.