Transient absorption and rotational relaxation in the liquid state

摘要

Transient absorption measurements have become a standard tool of picosecond spectroscopy in studying very fast level kinetics. In fluorescent samples stimulated fluorescence is a competing process. In liquid samples rotational diffusion is contributing due to the polarization of light. A repetitive picosecond spectrometer is presented that greatly reduces the occurrence of stimulated fluorescence due to its low power and is capable of separating rotational diffusion and level kinetics.