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Evaluation of the quasi correlated tight-binding (QCTB) model for describing polyradical character in polycyclic hydrocarbons

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journal contribution
posted on 06.03.2018, 11:22 by Anatoliy V. Luzanov, Felix Plasser, Anita Das, Hans Lischka
We present a verification and significant algorithmic improvement of the quasi-correlation tightbinding (QCTB) scheme (a H¨uckel-Hubbard-type model mimicking electron correlation) for describing effectively unpaired electrons in the spirit of Head-Gordon’s approach [M. Head-Gordon, Chem. Phys. Lett. 380, 488 (2003)]. For comparison purposes, results based on the high-level ab initio multireference averaged quadratic coupled cluster method previously computed in our works are invoked. In doing so, typical polyaromatic hydrocarbons (polyacenes, periacenes, zethrenes, and the Clar goblet) are studied. The evaluation shows that the QCTB H¨uckel-like scheme extended for electron correlation effects provides a qualitatively and in several cases also quantitatively good picture of the unpairing electrons in formally closed-shell electronic systems. Additionally, fairly large nanographene systems of triangulene structure (C426) and a perforated nanoribbon (C8860) have been treated at QCTB level. Two analytical model problems in the framework of QCTB prove the ability of this approximation to give a correct description of natural orbital occupancy spectra. For the studied QCTB scheme, an efficient algorithm is elaborated, and large-scale calculations of radical characteristics for nanographene networks with thousands of carbon atoms are possible.

Funding

This material is based upon work supported by the National Science Foundation under Project No. CHE-1213263, by the Austrian Science Fund (SFB F41, ViCom), and by the VSC Research Center funded by the Austrian Federal Ministry of Science, Research and Economy (BMWFW).

History

School

  • Science

Department

  • Chemistry

Published in

The Journal of Chemical Physics

Volume

146

Issue

6

Pages

064106 - 064106

Citation

LUZANOV, A.V. ...et al., 2017. Evaluation of the quasi correlated tight-binding (QCTB) model for describing polyradical character in polycyclic hydrocarbons. The Journal of Chemical Physics, 146: 064106.

Publisher

AIP

Version

VoR (Version of Record)

Publisher statement

This work is made available according to the conditions of the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International (CC BY-NC-ND 4.0) licence. Full details of this licence are available at: https://creativecommons.org/licenses/by-nc-nd/4.0/

Acceptance date

19/01/2017

Publication date

2017

Notes

This paper was accepted for publication in the journal The Journal of Chemical Physics and the definitive published version is available at https://doi.org/10.1063/1.4975196

ISSN

0021-9606

eISSN

1089-7690

Language

en

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Keywords

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