SPECTROSCOPY OF JET-COOLED AG2AU

Resonant two-photon ionization spectroscopy has been used to study the supersonically cooled metal cluster, Ag2Au. One electronic band syste m has been observed, with the origin band at 17525 cm-1. Vibronic prog ressions have been found and analyzed using a least-squares fitting pr ocedure. The molecule is assigned as belonging to the C2v point group in both the ground and the excited electronic states, and vibrational progressions in both of the two totally symmetric (a1) vibrational mod es have been identified, giving values of omega1'=200.15+/-0.49 cm-1 a nd omega2'=111.28+/-0.62 cm-1 for the excited electronic state of the (AgAgAu)-Ag-107-Ag-109-Au-197 isotopic modification. Anharmonicities x 11',x12', and x22' are also reported for the excited electronic state, along with lifetime measurements for several vibronic levels. This wo rk also places the ionization potential of Ag2Au in the range 5.00 les s-than-or-equal-to IP(Ag2Au) less-than-or-equal-to 6.42 eV. 0