Time-resolved photoelectron spectra of Pt2(N2)−

Pump-probe photoelectron detachment spectra of Pt2(N2)− have been measured using two subsequent fs-laser pulses. The time-resolved spectra show two parallel dissociation channels: photoinduced thermal desorption of N2 from the cluster “surface” as well as breaking of the intermetallic Pt-Pt bond. For both fragmentation channels the dissociation energy is less than 1.5 eV. Density-functional calculations predict a linear geometry of neutral and anionic Pt2(N2). The calculated electron affinity of the neutral linear cluster (3.2 eV) agrees reasonably with the experimental value of (2.8 ± 0.2) eV. Using the statistical RRK approach an intermetallic dissociation energy of 0.4 eV has been estimated from the measured dissociation rate.