Ranking the Properties Important for Understanding Noncovalent Bond Strength

The interaction energies within noncovalent bonds can be partitioned into electrostatic, induction, and dispersive attractive elements. A set of complexes comprising halogen, chalcogen, pnicogen, and tetrel bonds, are studied by quantum chemical calculations to assess how each of these components can be understood on the basis of properties of the constituent monomers. The variation of the electrostatic term, which accounts for over half of the total attractive energy, can be approximated, but with only modest accuracy, by combination of the maximum and minimum of the electrostatic potential on the two subunits. Induction represents a smaller contribution to the total, but is well connected with the NBO interorbital transfer energy, as opposed to the reciprocal of the HOMO-LUMO gap which behaves quite differently than IND. Of the various AIM parameters, both the bond critical point density and energy density are closely related to the full interaction energy.