FEMTOSECOND 2-PHOTON IONIZATION SPECTROSCOPY OF THE B-STATE OF NA3 CLUSTERS

We report time-resolved experiments studying the dynamics of the Na3 B -X system. Femtosecond pump-probe techniques combined with ion time-of -flight (TOF) and zero kinetic energy (ZEKE) photoelectron spectroscop y allow us to observe the three-dimensional wavepacket motion in the e xcited Na3 B state and in the Na3 X state. The ground state wavepacket is induced by stimulated emission pumping during the pump pulse. The X-state dynamics is dominated by the three vibrational modes of the Na 3. Furthermore we observed pseudorotational wavepacket motion in the B state. We do not observe a fragmentation of the B state within a time interval of 10 ps.