Resonant two-photon ionization spectroscopy of jet-cooled NiPt

Resonant two-photon ionization spectroscopy of jet-cooled NiPt has been used to investigate the possibility of <f-electron contributions to the bonding in this species. Based on an abrupt onset of predissociation, the bond strength of NiPt is assigned as D0 (NiPt) = 2.798 ? 0.003 eV. Comparisons of scans using ArF (6.42 eV) or F? (7.87 eV) radiation as the ionization laser yield IP (NiPt) = 8.02 ? 0.15 eV, from which we derive D0 (Ni+ -Pt) =2.41 ? 0.15 eV and D0 (Ni-Pt+) = 3.58 ? 0.35 eV. High resolution studies of the 6-0 and 8-0 bands of one of the three identifiable progressions demonstrate an ?'= 0 ??" = 0 transition with r'e = 2.3396 ? 0.0039? and ro" = 2.2078 ? 0.0023A. The short bond length and large bond strength of NiPt, as compared to the corresponding values (re = 2.330 + 0.003? and D0 = 2.34 + 0.10 eV) for the coinage metal analog, CuAu, demonstrate significant rf-orbital contributions to the bonding in NiPt.