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Download fileEvaluation of the quasi correlated tight-binding (QCTB) model for describing polyradical character in polycyclic hydrocarbons
journal contribution
posted on 2018-03-06, 11:22 authored by Anatoliy V. Luzanov, Felix PlasserFelix Plasser, Anita Das, Hans LischkaWe 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 PhysicsVolume
146Issue
6Pages
064106 - 064106Citation
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
AIPVersion
- 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
2017-01-19Publication date
2017Notes
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/10.1063/1.4975196ISSN
0021-9606eISSN
1089-7690Publisher version
Language
- en