FEMTOSECOND DYNAMICS OF BENZENE (NH3)(N) COMPLEXES IN HIGHLY EXCITED-STATES

The dynamics of benzene(NH3)(n) heteroclusters is studied with 170 fs laser pulses in a molecular beam. The clusters were excited to about 6 .2 eV, i.e, above the S-2 state of bare benzene. By varying the probe energy (3.1 and 4.65 eV) we examined the dynamics of internal conversi on and their dependence on the cluster size. The obtained time constan ts of internal conversion are in the order of 100 fs. The ultrafast dy namics were not observed before and show that earlier nanosecond studi es were only revealing the long-time behaviour after further relaxatio n and fragmentation of the vibrationally highly excited complexes.