title: Towards highly accurate ab initio thermochemistry of larger systems: benzene.
abstract: The high accuracy extrapolated ab initio thermochemistry (HEAT) protocol is applied to compute the total atomization energy (TAE) and the heat of formation of benzene. Large-scale coupled-cluster calculations with more than 1500 basis functions and 42 correlated electrons as well as zero-point energies based on full cubic and (semi)diagonal quartic force fields obtained with the coupled-cluster singles and doubles with perturbative treatment of the triples method and atomic natural orbital (ANO) triple- and quadruple-zeta basis sets are presented. The performance of modifications to the HEAT scheme and the scaling properties of its contributions with respect to the system size are investigated. A purely quantum-chemical TAE and associated conservative error bar of 5463.0 ± 3.1 kJ mol(-1) are obtained, while the corresponding 95% confidence interval, based on a statistical analysis of HEAT results for other and related molecules, is ± 1.8 kJ mol(-1). The heat of formation of benzene is determined to be 101.5 ± 2.0 kJ mol(-1) and 83.9 ± 2.1 kJ mol(-1) at 0 K and 298.15 K, respectively.
authors.affiliation: Institut für Physikalische Chemie, Universität Mainz, Jakob-Welder-Weg 11, D-55099 Mainz, Germany. harding@mail.utexas.edu
authors.forename: Michael E
authors.initials: ME
authors.lastname: Harding
authors.forename: Juana
authors.initials: J
authors.lastname: Vázquez
authors.forename: Jürgen
authors.initials: J
authors.lastname: Gauss
authors.forename: John F
authors.initials: JF
authors.lastname: Stanton
authors.forename: Mihály
authors.initials: M
authors.lastname: Kállay