Development of infrared electroabsorption spectroscopy for liquids

An infrared spectroscopic system has been constructed that is specifically designed for electroabsorption measurements of liquids. The system can dete ct electric-field-induced absorbance changes as small as one part in a mill ion, two orders of magnitude better than the conventional difference spectr um method using FT-IR. Electroabsorption spectra of liquid 1,2-dichloroetha ne have been measured. The observed absorbance changes have been explained in terms of two dominant mechanisms; the change in the trans-gauche equilib rium, and the orientational polarization of the gauche conformer. It is dem onstrated that infrared electroabsorption spectroscopy provides useful info rmation on otherwise inaccessible electric properties of molecules in liqui ds. (C) 2001 Elsevier Science B.V. All rights reserved.