Ultrafast fragmentation probability of the Na3 C state

Employing transient resonant two-color two-photon ionization spectroscopy in the picosecond regime, we have investigated vibrationally resolved fragmentation dynamics of the excited electronic C state of the sodium trimer. A simple energy level model describes the single exponential decay found for the temporal evolution of the transient spectra. For five different vibrational bands of the C state the lifetimes could be deduced, decreasing drastically with growing excitation energy from 1.12 ns to 12 ps. With the radiative decay time known to be 6 ns, fragmentation time constants and probabilities could be calculated, confirming that the C state represents the onset of the sodium trimerʹs predissociation.