QCT analysis of molecules containing the first and second period elements based on the PAEM

Abstract

Quantum chemical topology (QCT) is a branch of theoretical chemistry. We use QCT based on the potential acting on one electron in a molecule (PAEM) to systematically investigate polyatomic molecules containing the first and second period elements. The results and analyses for five series of molecules containing the first and second period elements are presented. The calculated topological characteristics of these molecules, namely, the partitions into atoms, the atomic charges and the absolute value of the PAEM at the bond critical point called Dpb, are compared with those obtained from the quantum theory of atoms in molecules (QTAIM). The values of the PAEMQCT atomic charge are moderate; they are smaller than those obtained from the QTAIM and larger than those obtained from the Hirshfeld method. In PAEMQCT, the Dpb can be utilized to measure the strength of the chemical bond, while in QTAIM method, the electron density at the bcp is related to the bond strength. There is a good linear correlation between the Dpb at the bcp in PAEMQCT and the electron density at the bcp in QTAIM, and their correlation coefficient R is 0.9165.