Abstract

The use of ultrashort laser pulses to photoinitiate chemical reactions in solution has lead to the observance of vibrational coherence transfer from reactant states into the product manifold. By resolving the wavepacket contributions in the transient response, the solvent influence on the reaction pathway may be probed. As a result, information regarding product state distributions and the existing offdiagonal density matrix elements becomes accessible. For many photochemical processes the initiation pulse must be in the ultraviolet spectral region. Therefore, a femtosecond pump/probe spectrometer, capable of delivering 70 fs; 5 μj 310 nm pulses, has been constructed for this purpose. It has enabled the study of the solvent sensitivity of wavepacket dynamics in two photochemical reactions; the photodissociation of HgI₂¹ and the photoisomerization of cis-stilbene. These experimental results, and an improvement in the time resolution of the femtosecond spectrometer will be summarized below.

© 1994 Optical Society of America