BOND STRENGTHS OF TRANSITION-METAL DIATOMICS - ZR-2, YCO, YNI, ZRCO, ZRNI, NBCO, AND NBNI

The observation of an abrupt predissociation threshold in an extremely congested electronic spectrum, has been used to measure the bond dissociation energies of the mixed early-late transition metal molecules YCo, YNi, ZrCo, ZrNi, NbCo, and NbNi. In these systems it is argued that predissociation occurs as soon as the ground separated atom limit is exceeded, providing values of D-0(0)(YCo) = 2.591 +/- 0.001 eV, D-0(0)(YNi) = 2.904 +/- 0.001 eV, D-0(0)(ZrCo) = 3.137 +/- 0.001 eV, D-0(0)(ZrNi) = 2.861 +/- 0.001 eV, D-0(0)(NbCo) = 2.729 +/- 0.001 eV, and D-0(0)(NbNi) = 2.780 +/- 0.001 eV. In addition, the bond strength of diatomic zirconium has been measured as D-0(0)(Zr-2) = 3.052 +/- 0.001 eV. A discussion of the Chemical bonding in the mixed early-late transition metal dimers and Zr-2 is presented;based on the measured bond energies of these species.