Ground and low-lying excited states of PtCN and PdCN: theoretical investigation including spin-orbit coupling

Abstract

Quantum chemical calculations for platinum monocyanide (PtCN) and palladium monocyanide (PdCN) were performed by density functional theory (DFT) and high-level ab initio methods such as the coupled-cluster singles and doubles with perturbative triples and multireference configuration interaction calculations including the Davidson correction (MRCI+Q). The molecular properties of the ground and low-lying excited states of PtCN and PdCN are calculated. Spin-orbit coupling (SOC) is also considered in the DFT and MRCI+Q calculations. The electronic ground states of PtCN and PdCN are the (2)Delta(5/2) and (2)Sigma(+)(1/2) states, respectively. In addition, the potential energy curves (PECs) of PtCN and PdCN are calculated with respect to the M-CN (M = Pt and Pd) coordinate. Both the scalar relativistic effects and SOC contribute to the determination of the ground state of PtCN to be the (2)Delta(5/2) state.