title: An Assessment of Density Functional Methods for Potential Energy Curves of Nonbonded Interactions: The XYG3 and B97-D Approximations.
abstract: A recently proposed double-hybrid functional called XYG3 and a semilocal GGA functional (B97-D) with a semiempirical correction for van der Waals interactions have been applied to study the potential energy curves along the dissociation coordinates of weakly bound pairs of molecules governed by London dispersion and induced dipole forces. Molecules treated in this work were the parallel sandwich, T-shaped, and parallel-displaced benzene dimer, (C6H6)2; hydrogen sulfide and benzene, H2S·C6H6; methane and benzene, CH4·C6H6; the methane dimer, (CH4)2; and the pyridine dimer, (C5H5N)2. We compared the potential energy curves of these functionals with previously published benchmarks at the coupled cluster singles, doubles, and perturbative triplets [CCSD(T)] complete-basis-set limit. Both functionals, XYG3 and B97-D, exhibited very good performance, reproducing accurate energies for equilibrium distances and a smooth behavior along the dissociation coordinate. Overall, we found an agreement within a few tenths of one kcal mol(-1) with the CCSD(T) results across the potential energy curves.
authors.affiliation: Center for Computational Molecular Science and Technology, School of Chemistry and Biochemistry and College of Computing, Georgia Institute of Technology, Atlanta, Georgia 30332-0400, Chemistry Department, University of Tennessee, 1416 Circle Drive, 552 Dabney-Buehler Hall, Knoxville, Tennessee 37996-1600, and Computer Science and Mathematics Division and Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Bethel Valley Road, P.O. Box 2008, Building 6012, Oak Ridge, Tennessee 37831-6367.
authors.forename: Álvaro
authors.initials: Á
authors.lastname: Vázquez-Mayagoitia
authors.affiliation: Center for Computational Molecular Science and Technology, School of Chemistry and Biochemistry and College of Computing, Georgia Institute of Technology, Atlanta, Georgia 30332-0400, Chemistry Department, University of Tennessee, 1416 Circle Drive, 552 Dabney-Buehler Hall, Knoxville, Tennessee 37996-1600, and Computer Science and Mathematics Division and Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Bethel Valley Road, P.O. Box 2008, Building 6012, Oak Ridge, Tennessee 37831-6367.
authors.forename: C David
authors.initials: CD
authors.lastname: Sherrill
authors.affiliation: Center for Computational Molecular Science and Technology, School of Chemistry and Biochemistry and College of Computing, Georgia Institute of Technology, Atlanta, Georgia 30332-0400, Chemistry Department, University of Tennessee, 1416 Circle Drive, 552 Dabney-Buehler Hall, Knoxville, Tennessee 37996-1600, and Computer Science and Mathematics Division and Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Bethel Valley Road, P.O. Box 2008, Building 6012, Oak Ridge, Tennessee 37831-6367.
authors.forename: Edoardo
authors.initials: E
authors.lastname: Aprà
authors.affiliation: Center for Computational Molecular Science and Technology, School of Chemistry and Biochemistry and College of Computing, Georgia Institute of Technology, Atlanta, Georgia 30332-0400, Chemistry Department, University of Tennessee, 1416 Circle Drive, 552 Dabney-Buehler Hall, Knoxville, Tennessee 37996-1600, and Computer Science and Mathematics Division and Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Bethel Valley Road, P.O. Box 2008, Building 6012, Oak Ridge, Tennessee 37831-6367.
authors.forename: Bobby G
authors.initials: BG
authors.lastname: Sumpter