Development of Multi-Color Time-Resolved Spectroscopy Methods for Investigating Molecular Systems*

Ultrafast transient absorption spectroscopy facilitates the study of a system’s electronic excited state dynamics. Employing a multi-color technique, the time evolution of excited states of a given target can be investigated in great detail. We have developed methods for performing multi-color experiments using a femtosecond UV (266nm) pulse obtained from a frequency tripled IR (800nm) pulse, in conjunction with soft x-rays from the synchrotron at the Advanced Light Source (ALS). We are additionally working towards developing similar techniques with multi-color, multi-pulse schemes using extreme ultraviolet light from a high harmonic generation (HHG) source as a probe. We also present reflectivity measurements of different mirror coatings, that allow us to select relevant energies from the HHG source.