Thermodynamic properties of some ruthenium gaseous species
Résumé
The review of thermodynamic data of ruthenium gaseous compounds shows large uncertainties motivating the use of quantum chemical methods to reduce the level of discrepancies. Different quantum chemical methods have been investigated (DFT, CASSCF, MRCI, CASPT2, CCSD(T)) in order to predict the geometrical parameters, the energetics including electronic correlation, and spin-orbit coupling. The most suitable method for ruthenium compounds corresponds to TPSSh-5%HF for geometry optimization, followed by CCSD(T) with complete basis set (CBS) extrapolations for the calculation of the total electronic energies. This methodology yields accurate standard enthalpies of formation in excellent agreement with the most reliable experimental data, and provide for the others species reduced uncertainties.