Picosecond pump–probe and polarization techniques in supersonic molecular beams: Measurement of ultrafast vibrational-rotational dephasing and coherence

In the last few years, the time-resolved dynamics of collisionless intramolecular vibrational-energy redistribution (IVR) [1] has been probed [2] using picosecond excitation and fluorescence detection. By this method new information on IVR, coherence and photochemical changes (e.g., trans-cis isomerization) has been obtained. [2,3] However, in a number of cases the (early time) primary step following picosecond excitation could not be resolved simply because the time resolution was limited to ~50ps.