Abstract

The high intensity, resolution, and brightness of the free electron laser (FEL) radiation is now making possible pump-probe experiments of excited state lifetimes in the picosecond domain in energy ranges not previously attainable by standard lasers. In addition, the short pulses will make possible electron TOF studies for measuring threshold photoelectron spectra with resolutions to 1 cm^-1. The major requirement for pump-probe experiment is that the sum of the two laser energies be greater than the ionization potential of the molecule being investigated. The FEL can be used either as a pump to investigate high energy states, or as a probe for low energy states excited by infra-red or visible lasers. TPES of cold molecules will provide new information about vibrational modes in ions and structural information from the analysis of the rotational structure.

© 1988 Optical Society of America