title: Benzene Dimer: Dynamic Structure and Thermodynamics Derived from On-the-Fly ab initio DFT-D Molecular Dynamic Simulations.
abstract: The dynamic nature of the benzene dimer was explored by on-the-fly molecular dynamics simulations based on the DFT-D method covering the dispersion energy. An all-electron DFT was performed at the BLYP/TZVP level. The parameters in the dispersion correction term were fitted to mimic the benchmark CCSD(T)/complete basis set limit potential energy curves for both the parallel-displaced (PD) and T-shaped (TS) structures of the dimer exactly. A dynamic description is important at temperatures above 10 K, where interconversion between the TS and PD structures is possible and a mixture of these two species exists. The higher the temperature, the more dominant the TS structure because of a favorable entropic contribution to the free energy. An analysis of the TS structures revealed that the symmetric c2v structure, a low-lying transition state, is practically not populated and that the tilted cs TS structure is prevalent. This finding is in perfect agreement with infrared spectroscopy.
authors.affiliation: Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic and Center for Biomolecules and Complex Molecular Systems, Flemingovo nám. 2, 166 10 Prague 6, Czech Republic.
authors.forename: Jan
authors.initials: J
authors.lastname: Řezáč
authors.affiliation: Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic and Center for Biomolecules and Complex Molecular Systems, Flemingovo nám. 2, 166 10 Prague 6, Czech Republic.
authors.forename: Pavel
authors.initials: P
authors.lastname: Hobza