title: Density-fitted open-shell symmetry-adapted perturbation theory and application to π-stacking in benzene dimer cation and ionized DNA base pair steps.
abstract: Symmetry-Adapted Perturbation Theory (SAPT) is one of the most popular approaches to energy component analysis of non-covalent interactions between closed-shell systems, yielding both accurate interaction energies and meaningful interaction energy components. In recent years, the full open-shell equations for SAPT up to second-order in the intermolecular interaction and zeroth-order in the intramolecular correlation (SAPT0) were published [P. S. Zuchowski et al., J. Chem. Phys. 129, 084101 (2008); M. Hapka et al., ibid. 137, 164104 (2012)]. Here, we utilize density-fitted electron repulsion integrals to produce an efficient computational implementation. This approach is used to examine the effect of ionization on π-π interactions. For the benzene dimer radical cation, comparison against reference values indicates a good performance for open-shell SAPT0, except in cases with substantial charge transfer. For π stacking between hydrogen-bonded pairs of nucleobases, dispersion interactions still dominate binding, in spite of the creation of a positive charge.
authors: School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, Georgia 30332-0400, USA.
authors: Jérôme F
authors: JF
authors: Gonthier
authors: School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, Georgia 30332-0400, USA.
authors: C David
authors: CD
authors: Sherrill
mesh_terms: D020029:Base Pairing; D001554:Benzene / Q000737:chemistry*; D002412:Cations / Q000737:chemistry*; D004247:DNA / Q000737:chemistry*; D019281:Dimerization; D006860:Hydrogen Bonding; D007477:Ions / Q000737:chemistry; D008956:Models, Chemical; D011789:Quantum Theory
chemical_list: D002412:Cations; D007477:Ions; D004247:DNA; D001554:Benzene