ACOUSTIC RELAXATION MECHANISMS IN O-FLUOROTOLUENE AND P-FLUOROTOLUENE

The molecular mechanisms of rotational-isomeric and structural relaxat ions in liquid o- and p-fluorotoluene are considered on the basis of a coustic spectra. It was experimentally established that, near the free zing point, o- and p-fluorotoluene has two conformal isomers. The enth alpies and rates of transition governed by the hindered rotation of th e methyl group are computed. In the investigated temperature range (18 3-493 K), the structural relaxation may be described by the reactions of breaking and formation of weak intermolecular bonds. The minimum in the temperature dependence of the structural relaxation time is deter mined by the interrelation of the rate constants of the forward and re verse reactions. The thermodynamic and kinetic parameters of the struc tural reconstruction are calculated.