Potential energy surfaces of OsCO

Potential energy surfaces for the low-lying states of osmium carbon monoxide (OsCO) have been studied using the complete active space multi-configuration self-consistent field (CAS-MCSCF) followed by multireference singles+doubles configuration interaction (MRSDCI). Additionally, spin–orbit effects were included through the relativistic configuration interaction method. It is found that the ground state of OsCO is an 0+ spin–orbit state which is a mixture of 3Σ− and 1Σ+. Spin–orbit coupling not only splits the various electronic states of OsCO but also mixes different electronic states.