Picosecond Transient Raman Spectroscopy Using the High Repetition Rate, Amplified, Synchronously Pumped Dye Laser

Abstract

We are using picosecond transient resonance Raman spectroscopy to study the structures of the first excited singlet states of trans-stilbene (tS) and diphenylbutadiene (DPB).[1–4] The importance of cis-trans photoisomerization in the diphenylpolyenes as model systems for olefin isomerization is well established and has been reviewed.[5.6] The direct structural and dynamical information obtained by transient Raman spectroscopy is a powerful adjunct to fluorescence and absorption measurements. The observed vibrational frequencies of the excited state provide considerable information about its potential energy surface. This is particularly important in the diphenylpolyenes when considering mechanisms for energy transfer from the optical modes to reaction coordinates. In addition, the intensities in the transient resonance Raman spectra reflect the character of higher electronic states.

We dedicate this paper to the memory of Joseph Forrest Palmer, who died June 3, 1985, at the age of 23. in a rock climbing accident.