Orientational diffusion of n-alkyl cyanides

Abstract

Ultrafast optical Kerr effect spectroscopy has been used to study thetemperature-dependent orientational dynamics of a series of nitriles withn-alkyl chains ranging from one to 11 carbons in length. In all cases the orientationaldiffusion is found to be described by a single-exponential decay. Analysis of theorientational correlation times using the Debye–Stokes–Einstein equation suggests that themolecules adopt extended configurations and reorient as rigid rods. The liquids withshorter alkyl chains undergo an apparent ordering transition as they are cooled.