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arXiv · 1512.03229

Hückel--Hubbard-Ohno modeling of $\boldsymbolπ$-bonds in ethene and ethyne with application to trans-polyacetylene

Máté Timár·Gergely Barcza·Florian Gebhard·Libor Veis·Örs Legeza
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Abstract

Quantum chemistry calculations provide the potential energy between two carbon atoms in ethane (H$_3$C$-$CH$_3$), ethene (H$_2$C$=$CH$_2$), and ethyne (HC$\equiv$CH) as a function of the atomic distance. Based on the energy function for the $σ$-bond in ethane, $V_σ(r)$, we use the Hückel model with Hubbard--Ohno interaction for the $π$~electrons to describe the energies $V_{σπ}(r)$ and $V_{σππ}(r)$ for the $σπ$ double bond in ethene and the $σππ$ triple bond in ethyne, respectively. The fit of the force functions shows that the Peierls coupling can be estimated with some precision whereas the Hubbard-Ohno parameters are insignificant at the distances under consideration. We apply the Hückel-Hubbard-Ohno model to describe the bond lengths and the energies of elementary electronic excitations of trans-polyacetylene, (CH)$_n$, and adjust the $σ$-bond potential for conjugated polymers.

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Máté Timár, Gergely Barcza, Florian Gebhard, Libor Veis, Örs Legeza. 2015-12-10. Hückel--Hubbard-Ohno modeling of $\boldsymbolπ$-bonds in ethene and ethyne with application to trans-polyacetylene. https://doi.org/10.1039/c6cp00726k

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