MNDO parameterized hybrid SLG/SCF method as used for molecular modeling of Zn(II) complexes

Abstract

The McWeeny's group functions technique is a natural way tointroduce local description into quantum chemistry. It can also serve as a basis for constructing numerically effective computational schemes with almost linear scaling of computational costs with the size of a system. In this study, we apply it to the coordination compounds of Zn(II)-containing ligands with nitrogen and oxygen donor atoms. In these compounds, the electron group corresponding to the metal vacant 4s-and 4p-atomic orbitals (AOs) of the Zn 2ϩ ion and its closest coordination sphere formed by the lone pairs (LP) located on the donor atoms naturally separates. This group, designated metal and lone pairs (MLP), is described by the SCF wave function within the hybrid scheme of strictly local geminals/self-consistent field (SLG/SCF). The SLC/ SCF scheme is based on the group function approach combining different descriptions for different electron groups: two-electron two-center bonds are described by geminals (SLG groups), while all the remaining electron groups are described by Slater determinants in the one-electron (SCF) approximation (SCF groups). The original MNDO Hamiltonian parameterization for the Zn atom is adjusted for correct description of geometry of the complexes.