Quantifying Electron Correlation of the Chemical Bond
journal contributionposted on 12.04.2017, 00:00 by James L. McDonagh, Arnaldo F. Silva, Mark A. Vincent, Paul L. A. Popelier
The Interacting Quantum Atoms (IQA) method is used to analyze the correlated part of the Møller–Plesset (MP) perturbation theory two-particle density matrix. Such an analysis determines the effects of electron correlation within atoms and between atoms, which covers both bonds and nonbonded through-space atom–atom interactions within a molecule or molecular complex. Electron correlation lowers the energy of the atoms at either end of a bond, but for the bond itself, it can be stabilizing or destabilizing. Bonds are described in a two-dimensional world of exchange and charge transfer, where covalency is not the opposite of ionicity.