title: Benzene Dimer: High-Level Wave Function and Density Functional Theory Calculations.
abstract: High-level OVOS (optimized virtual orbital space) CCSD(T) interaction energy calculations (up to the aug-cc-pVQZ basis set) and various extrapolations toward the complete basis set (CBS) limit are presented for the most important structures on the benzene dimer potential energy surface. The geometries of these structures were obtained via an all-coordinate gradient geometry optimization using the DFT-D/BLYP method, covering the empirical dispersion correction fitted exclusively for this system. The fit was carried out against two estimated CCSD(T)/CBS potential energy curves corresponding to the distance variation between two benzene rings for the parallel-displaced (PD) and T-shaped (T) structures. The effect of the connected quadruple excitations on the interaction energy was estimated using the CCSD(TQf) method in a 6-31G*(0.25) basis set, destabilizing the T and T-shaped tilted (TT) structures by ≈0.02 kcal/mol and the PD structure by ≈0.04 kcal/mol. Our best CCSD(T)/CBS results show, within the error bars of the applied methodology, that the energetically lowest-lying structure is the TT structure, which is nearly 0.1 kcal/mol more stable than the almost isoenergetic PD and T structures. The specifically parametrized DFT-D/BLYP method leads to a correct energy ordering of the structures, with the errors being smaller by 0.2 kcal/mol with respect to the most accurate CCSD(T) values.
authors.affiliation: Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, v. v. i., Flemingovo nám. 2, 166 10 Praha 6, Czech Republic, Department of Physical and Theoretical Chemistry, Faculty of Natural Sciences, Comenius University, Mlynská Dolina, 842 15 Bratislava 4, Slovak Republic, and Department of Physical Chemistry, Palacky University, tr. Svobody 26, 771 46, Olomouc, Czech Republic.
authors.forename: M
authors.initials: M
authors.lastname: Pitoňák
authors.affiliation: Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, v. v. i., Flemingovo nám. 2, 166 10 Praha 6, Czech Republic, Department of Physical and Theoretical Chemistry, Faculty of Natural Sciences, Comenius University, Mlynská Dolina, 842 15 Bratislava 4, Slovak Republic, and Department of Physical Chemistry, Palacky University, tr. Svobody 26, 771 46, Olomouc, Czech Republic.
authors.forename: P
authors.initials: P
authors.lastname: Neogrády
authors.affiliation: Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, v. v. i., Flemingovo nám. 2, 166 10 Praha 6, Czech Republic, Department of Physical and Theoretical Chemistry, Faculty of Natural Sciences, Comenius University, Mlynská Dolina, 842 15 Bratislava 4, Slovak Republic, and Department of Physical Chemistry, Palacky University, tr. Svobody 26, 771 46, Olomouc, Czech Republic.
authors.forename: J
authors.initials: J
authors.lastname: Rezáč
authors.affiliation: Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, v. v. i., Flemingovo nám. 2, 166 10 Praha 6, Czech Republic, Department of Physical and Theoretical Chemistry, Faculty of Natural Sciences, Comenius University, Mlynská Dolina, 842 15 Bratislava 4, Slovak Republic, and Department of Physical Chemistry, Palacky University, tr. Svobody 26, 771 46, Olomouc, Czech Republic.
authors.forename: P
authors.initials: P
authors.lastname: Jurečka
authors.affiliation: Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, v. v. i., Flemingovo nám. 2, 166 10 Praha 6, Czech Republic, Department of Physical and Theoretical Chemistry, Faculty of Natural Sciences, Comenius University, Mlynská Dolina, 842 15 Bratislava 4, Slovak Republic, and Department of Physical Chemistry, Palacky University, tr. Svobody 26, 771 46, Olomouc, Czech Republic.
authors.forename: M
authors.initials: M
authors.lastname: Urban
authors.affiliation: Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, v. v. i., Flemingovo nám. 2, 166 10 Praha 6, Czech Republic, Department of Physical and Theoretical Chemistry, Faculty of Natural Sciences, Comenius University, Mlynská Dolina, 842 15 Bratislava 4, Slovak Republic, and Department of Physical Chemistry, Palacky University, tr. Svobody 26, 771 46, Olomouc, Czech Republic.
authors.forename: P
authors.initials: P
authors.lastname: Hobza