Abstracts

G.M. Turner, M.C. Beard, D.S. Venables, and C.A. Schmuttenmaer, "A Direct Measurement of Intermolecular Solvation Dynamics using Time-Resolved THz Spectroscopy (TRTS)," Photoinduced Charge Transfer: Proceedings of the 10th Annual Symposium of the NSF Center, University of Rochester, New York 26 - 29 July 1999, ed. L. Rothberg, (World Scientific, 2000) 223-232.

Abstract
Low frequency intermolecular solvent dynamics in the vicinity of a photoexcited dye molecule have been probed directly with time-resolved THz pulse spectroscopy. Unlike typical time-resolved laser studies, the spectrum of both the solvent and the solute is monitored. We have investigated the dynamics of TBNC (2,11,20,29-tetra-tert-butyl-2,3-naphthalocyanine) in chloroform, benzene, toluene, and pyridine. The far-infrared (FIR) spectrum from 7 cm-1 to 60 cm-1 was measured as a function of delay time after photoexcitation with an 800 nm pulse. The temporal resolution was approximately 200 fs. In all three solvents, a low frequency feature in the vicinity of 12 to 15 cm-1 appears within a few hundred fs after photoexcitation. A higher frequency absorption near 50 to 60 cm-1 occurs 250 to 350 fs later. One plausible mechanism for this behavior is discussed.