Defining the contributions of permanent electrostatics, Pauli repulsion, and dispersion in density functional theory calculations of intermolecular interaction energies

Abstract

In energy decomposition analysis of Kohn-Sham density functional theory calculations, the so-called frozen (or pre-polarization) interaction energy contains contributions from permanent electrostatics, dispersion, and Pauli repulsion. The standard classical approach to separate them suffers from several well-known limitations. We introduce an alternative scheme that employs valid antisymmetric electronic wavefunctions throughout and is based on the identification of individual fragment contributions to the initial supersystem wavefunction as determined by an energetic optimality criterion. The density deformations identified with individual fragments upon formation of the initial supersystem wavefunction are analyzed along with the distance dependence of the new and classical terms for test cases that include the neon dimer, ammonia borane, water-Na(+), water-Cl(-), and the naphthalene dimer.

Perspective: Found in translation: Quantum chemical tools for grasping non-covalent interactions

“…56,124,125,139,179,219,220 The first avenue has already lead to a more stable definition of charge transfer 77,96 or London dispersion terms. 36 Alternatively, SAPT has recently been expanded to treat intramolecular interactions 123,124,128 and open-shell systems. 139 The latter achievement could be a major step toward the development of a multi-reference (i.e., able to treat bond-breaking phenomena) or even an excited-state variant of SAPT.…”

“…5 and 6 are illustrative: for the benzene dimer, the dispersion component is correctly transferred to the correlation term (CORR) using GKS-EDA, but confusingly for the water dimer the dispersion contribution is redistributed amongst each of the other components. More recently, Head-Gordon and co-workers 36,56 investigated this problem using ALMO-EDA. They defined the dispersion term as the difference between the interaction energies from the exchange-correlation component of the functional that comprises dispersion and from exchange-correlation component of a "dispersion-free" (i.e., exact-exchange of rev-PBE 57 ) functional.…”

Doses of Immunogen Contribute to Specificity Spectrums of Antibodies against Aflatoxin

“…Antibody–antigen interactions are indispensable to immunoassay, although the interactions at the molecular level are, in general, undetermined. It is suggested that the antigen–antibody recognition is based on steric criteria and on interactions resulting from the electronic properties of the molecules [19], so the position space or quantity of antigen epitopes may play a significant role in antigen–antibody interaction. For example, in the sketch in Figure 4, the same hapten conjugates to the carrier protein may turn up different antigen epitopes, which means the antigenic determinants are different, with the difference containing the length of the spacer arm, position space of the antigen epitopes, the coupling ratio of the hapten and the carrier protein, etc.…”

Energy Decomposition Analysis Based on Absolutely Localized Molecular Orbitals for Large-Scale Density Functional Theory Calculations in Drug Design

“…Additionally, it is important to note the development of a number of alternative approaches to the above theory such as the scheme of Horn et al 56 for investigating (decomposing) the frozen interaction in KS DFT calculations and the density-based energy decomposition analysis (DEDA) of Wu 57 that calculates the frozen density interaction in a variational manner.…”