Electronic structure and thermodynamic properties of YIrC and YIrC2

Ab initio calculations including Mّller-Plesset second order perturbation (MP2), density functional theory (DFT), complete active space self-consistent field (CASSCF) and multireference singles and doubles configuration interaction (MRSDCI) computations are carried out for the YIrC adn YC2Ir molecules. Several alternative structures are optimized and the vibrational frequencies are computed. Thermodynamic properties such as the Gibbs energy functions and heat content functions are computed and compared with the available experimental data. The nature of chemical bonding in these molecules is analyzed.