The role of the long-range exchange corrections in the description of electron delocalization in aromatic species

Abstract

In this article, we address the role of the long-range exchange corrections in description of the cyclic delocalization of electrons in aromatic systems at the density functional theory level. A test set of diversified monocyclic and polycyclic aromatics is used in benchmark calculations involving various exchange-correlation functionals. A special emphasis is given to the problem of local aromaticity in acenes, which has been a subject of long-standing debate in the literature. The presented results indicate that the noncorrected exchange-correlation functionals significantly overestimate cyclic delocalization of electrons in heteroaromatics and aromatic systems with fused rings, which in the case of acenes leads to conflicting local aromaticity predictions from different criteriaThe research was supported in part by the Foundation for Polish Science (FNP START 2015, stipend 103.2015, DS), National Science Centre, Poland (NCN SONATA, grant 2015/17/D/ST4/ 00558, DS) as well as the PL-Grid Infrastructure of the Academic Computer Centre CYFRONET, with the calculations performed on cluster platforms Zeus and Prometheus. MS thanks for the support of the Ministerio de Economía y Competitividad of Spain (Project CTQ2014-54306-P), Generalitat de Catalunya (project number 2014SGR931, Xarxa de Referència en Química Teòrica i Computacional, and ICREA Academia prize), and European Fund for Regional Development (FEDER grant UNGI10-4E-801