Noncovalent interactions are ubiquitous in nature. These are present in van der Waals (vdW) molecules in the gas phase. However, theoretical study of these molecules is challenging due to the difficulty of treating dispersion. An appropriate methodology is to use density-functional theory (DFT) with dispersion corrections such as the exchange-hole dipole moment (XDM) model [1]. Computation of the potential-energy surfaces of simple vdW molecules consisting of a rare gas atom (He, Ne, Ar, and Kr) and a linear molecule (CO, N2, HF, HBr, CO2, OCS, HCN, and C2H2) is a sensitive test for XDM. Based on comparisons with accurate reference data, XDM generally predicts accurate bond lengths, bond angles, and binding energies for the majority of these vdW molecules. However, in some cases, DFT with XDM performs poorly and the potential energy surfaces for these molecules are investigated in more detail to understand whether the source of the errors is the base functional or the XDM dispersion energy.References:[1] Otero-de-la-Roza, A.; Johnson, E. R. J. Chem. Phys. 2013  , 138, 204109.

Potential energy surfaces of van der Waals molecules

248th National Meeting (2014)

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