title: A Computational Study on the Ground and Excited States of Nickel Silicide.
abstract: Nickel silicide has been studied with a range of computational methods to determine the nature of the Ni-Si bond. Additionally, the physical effects that need to be addressed within calculations to predict the equilibrium bond length and bond dissociation energy within experimental error have been determined. The ground state is predicted to be a (1)Σ(+) state with a bond order of 2.41 corresponding to a triple bond with weak π bonds. It is shown that calculation of the ground state equilibrium geometry requires a polarized basis set and treatment of dynamic correlation including up to triple excitations with CR-CCSD(T)L resulting in an equilibrium bond length of only 0.012 Å shorter than the experimental bond length. Previous calculations of the bond dissociation energy resulted in energies that were only 34.8% to 76.5% of the experimental bond dissociation energy. It is shown here that use of polarized basis sets, treatment of triple excitations, correlation of the valence and subvalence electrons, and a Λ coupled cluster approach is required to obtain a bond dissociation energy that deviates as little as 1% from experiment.
authors: Department of Chemistry and Center for Advanced Scientific Computing and Modeling (CASCaM), University of North Texas , Denton, Texas 76203-5017, United States.
authors: George
authors: G
authors: Schoendorff
authors: Department of Chemistry and Center for Advanced Scientific Computing and Modeling (CASCaM), University of North Texas , Denton, Texas 76203-5017, United States.
authors: Alexis R
authors: AR
authors: Morris
authors: Department of Chemistry and Center for Advanced Scientific Computing and Modeling (CASCaM), University of North Texas , Denton, Texas 76203-5017, United States.
authors: Emily D
authors: ED
authors: Hu
authors: Department of Chemistry and Center for Advanced Scientific Computing and Modeling (CASCaM), University of North Texas , Denton, Texas 76203-5017, United States.
authors: Angela K
authors: AK
authors: Wilson