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Knudsen cell mass spectrometric equilibrium measurements together with theoretical computations have been employed to gain structural and thermodynamic information of the OsC and OsC[sub 2] molecules. Several levels of theory have been applied to determine the structures, molecular parameters, and physico-chemical properties of OsC(g) and OsC[sub 2](g), and their singly charged ions. Complete active space self-consistent field (CASSCF) calculations were performed on the apparent [sup 3]Σ[sup -] ground state and first [sup 3]Δ excited state of OsC. From the analyzed gaseous equilibria and the thermal functions calculated from the computed molecular parameters, the following atomization enthalpies, Δ[sub a]H[sub 0][sup o](OsC,g) and Δ[sub a]H[sub 0][sup o](OsC[sub 2],g), and enthalpies of formation, Δ[sub f]H[sub 298.15][sup o](OsC,g) and Δ[sub f]H[sub 298.15][sup o](OsC[sub 2],g), in kJ mol-1, have been obtained: OsC, 605.6±14.0 and 895.4±14.0; OsC[sub 2], 1154.6±18.0 and 1059.5±18.0. The results have been compared with those for the other platinum metal carbides and oxides.


Copyright 2001 American Institute of Physics. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics.

The following article appeared in Structure and thermodynamic stability of the OsC and OsC2 molecules by theoretical calculations and by Knudsen cell mass spectrometry. Meloni, G. and Thomson, L. M. and Gingerich, K. A., The Journal of Chemical Physics, 115, 4496-4501 (2001) and may be found at



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