Theoretical investigations of nickel dicarbide

CHED 1043

Brendan L. Yonke1, Michael Howart1, and Jie Song, jiesong@umich.edu2. (1) Department of Chemistry and Biochemistry, University of Michigan - Flint, Flint, MI 48502, (2) Department of Chemistry and Biochemistry, University of Michigan-Flint, 303 E. Kearsley St., Flint, MI 48502
Transition metal carbides (TMCs) have received considerable attention from experimentalists and theoreticians because of their unique physical and chemical properties. Currently, experimental and theoretical understanding of TMCs is very limited. Due to the partially filled d shells of transition metal atoms, TMCs have a high density of low-lying atomic states that require multi-reference methods and large active spaces for analysis, which is shown from the previous studies. However, multi-reference methods are restricted by the size of the active space and the traditional way is to freeze specific orbitals within the active space and ignore the single and double excitations from these orbitals. It may be problematic. In this research, a new MRPT approach involving the truncation of the large active space was used to investigate the ground and low-lying excited states of nickel dicarbide.