Ultrafast relaxation dynamics of optically excited electrons in Ni3-

Photon-induced ultrafast energy dissipation in small isolated Ni-3(-) has been studied by two-color pump-probe photoelectron spectroscopy. The time-resolved photoelectron spectra clearly trace the path from a single-electron excitation to a thermalized cluster via both inelastic electron-electron scattering and electron-vibrational coupling. The relatively short electron-electron-scattering time of 215 fs results from the narrow energy spread of the partially filled d levels in this transition-metal cluster. The relaxation dynamics is discussed in view of the cluster size and in comparison to the totally different relaxation behavior of s/p-metal clusters

Photon-induced thermal desorption of CO from small metal-carbonyl clusters

Thermal CO desorption from photoexcited free metal-carbonyl clusters has been resolved in real time using two-color pump-probe photoelectron spectroscopy. Sequential energy dissipation steps between the initial photoexcitation and the final desorption event, e.g., electron relaxation and thermalization, have been resolved for Au-2(CO)(-) and Pt-2(CO)(5)(-). The desorption rates for the two clusters differ considerably due to the different numbers of vibrational degrees of freedom. The unimolecular CO-desorption thresholds of Au-2(CO)(-) and Pt-2(CO)(5)(-) have been approximated by means of a statistical Rice-Ramsperger-Kassel calculation using the experimentally derived desorption rate constants

Photoelectron spectroscopy of GdO

We present vibrationally resolved photoelectron spectra of the gadolinium oxide anion GdO- using 3.495-eV photons. The molecules have been produced in a laser vaporization source and have been mass selected prior to the detachment process. An electron affinity of 1.19+/-0.1 eV is measured. The vibrational frequencies of the ground state and the first excited state are determined to be 790+/-40 and 887+/-40 cm(-1), respectively. A group of states at 2.6-eV binding energy is interpreted to correlate with the 4f(7)(S-8) 6p(P-2(1/2)) \Ohm(6p)\=1/2 configuration