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All electron ab initio Hartree–Fock (HF) and configuration interaction (CI) calculations have been applied to investigate the low-lying electronic states of the NiGe molecule. The ground state of the NiGe molecule is predicted to be 1Σ+. The chemical bond in the 1Σ+ ground state is a double bond composed of one σ and one π bond. The σ bond is due to a delocalized molecular orbital formed by combining the Ni 4s and the Ge 4pσ orbitals. The π bond is a partly delocalized valence bond, originating from the coupling of the 3dπ hole on Ni with the 4pπ electron on Ge. The low-lying electronic states of the NiGe molecule have all been characterized by the symmetry of the hole in the 3d shell of Ni. The dissociation energy of the NiGe molecule has been determined from our high temperature mass spectrometric equilibrium data in combination with the theoretical results as D○0 =286.8±10.9 kJ mol-1. The standard heat of formation of the NiGe molecule has been obtained as ΔH○f,298 =514±12 kJ mol-1. [ABSTRACT FROM AUTHOR]

In the present work we present all-electron ab initio Hartree–Fock (HF) and configuration interaction (CI) calculations of six electronic states of the PdGe molecule. The molecule is predicted to have a 3Π ground state and two low-lying excited states 3Σ- and 1Σ+. The electronic structure of the PdGe molecule has been rationalized in a simple molecular orbital picture. As part of the PdGe molecule the Pd atom essentially retains its (4d)10 ground term configuration. The chemical bond in the PdGe molecule has been interpreted in terms of donation and backdonation of charge. The bond is polar with a small charge transfer from the Pd to the Ge atom. The dissociation energy of the PdGe molecule has been determined from the mass spectrometric equilibrium data combined with the theoretical results as D00 =252.0±10.5 kJ mol-1. [ABSTRACT FROM AUTHOR]

The equilibria involving the gaseous species above the Y–Ge and Y–Si alloy systems have been experimentally investigated by the high temperature mass spectrometer technique. The gaseous molecules YGe, YSi, and YSi2 were identified and their partial pressures were measured as a function of temperature. The experimentally determined reaction enthalpies were combined with appropriate literature data to obtain the following atomization energies, ΔH○a,0 and standard heats of formation, ΔH○f,298 , in kJ mol-1: YGe, 275.4 ± 11.4 and 522.4 ± 11.4; YSi, 253.8 ± 17.3 and 625.3 ± 17.3; YSi2, 800 ± 21 and 528 ± 21. [ABSTRACT FROM AUTHOR]