Abstract

Femtosecond nonlinear optical spectroscopy has proven to be a powerful tool with which to probe both the inertial and diffusive dynamics of molecular liquids.¹ Only very recently have these techniques been applied to the study of dynamics in complex, strongly-interacting Hydrogen-bonding (H-bonding) liquids.² We present here new results on the study of neat liquid acetic acid, CH₃CO₂H. The measurements of the inertial and diffusive dynamics were made using the optical-heterodyne-detected, optical-Kerr-effect (OHD-OKE) technique, which is an electronically non-resonant polarization spectroscopy providing a signal linear in the third-order nonlinear-optical response.^1a Our measurements have been made as a function of sample temperature, with data taken at 19 and 108 °C. The melting and boiling points of acetic acid are ca. 16.2 and 117 °C, respectively, so our measurements have probed the extremes of the liquid phase. One of the most important uses for such ultrafast solvent relaxation data is to predict the rate of solvent-limited chemical reactions in solution, particularly adiabatic electron-transfer reactions.

© 1994 Optical Society of America