Chapter 13
Localized Structures at the Hückel Level,
a Hückel-Derived Valence Bond Method
Yannick Carissan, Nicolas Goudard, Denis Hagebaum-Reignier
and Stéphane Humbel
Abstract A simple Hückel Hamiltonian is used and modified to describe localized
states, where the electron pairs are confined to bonds between two atoms, or to lone
pairs. The electronic delocalization can be considered either as a mixture of these
localized states, or through a standard Hückel calculation. The two Hückel-Lewis
methods described here attempt to find the coefficients of the mixture, based on
energy or overlap consistence with the standard Hückel results. After the description of the two methods, test examples are used to show advantages and drawbacks
of the different approaches. In any case, the results are compared to the NBO-NRT
approach which is used on the electronic density obtained from standard DFT
hybrids calculations such as B3LYP/6-31+G(d). This chapter ends with an introduction to the HuLiS program in which the two methods are implemented.
This contribution is concerned with two approaches, called the Hückel-Lewis
(HuLiS) family of methods, that aim at associating a weight to a topological
envision of the electronic structure of a molecule. These methods are embedded in
the HuLiS code, which will also be briefly described. HuLiS targets primarily at a
classroom use, and is limited to planar p-conjugated systems. Our approach has
proved to be consistent with more elaborated methods such as the Natural Bond
Orbital (NBO)-based methods using Density Functional Theory (DFT) electronic
densities, or Valence Bond (VB) approaches [1]. It also has an appreciable
Y. Carissan (&) Á N. Goudard Á D. Hagebaum-Reignier Á S. Humbel
Aix Marseille Université, Centrale Marseille, CNRS, iSm2, UMR 7313,
13397 Marseille, France
e-mail: yannick.carissan@univ-amu.fr
N. Goudard
e-mail: nicolas.goudard@univ-amu.fr
D. Hagebaum-Reignier
e-mail: denis.hagebaum-reignier@univ-amu.fr
S. Humbel
e-mail: stephane.humbel@univ-amu.fr
© Springer International Publishing Switzerland 2016
R. Chauvin et al. (eds.), Applications of Topological Methods
in Molecular Chemistry, Challenges and Advances in Computational
Chemistry and Physics 22, DOI 10.1007/978-3-319-29022-5_13
337
Localized Structures at the Hückel Level,
a Hückel-Derived Valence Bond Method
Yannick Carissan, Nicolas Goudard, Denis Hagebaum-Reignier
and Stéphane Humbel
Abstract A simple Hückel Hamiltonian is used and modified to describe localized
states, where the electron pairs are confined to bonds between two atoms, or to lone
pairs. The electronic delocalization can be considered either as a mixture of these
localized states, or through a standard Hückel calculation. The two Hückel-Lewis
methods described here attempt to find the coefficients of the mixture, based on
energy or overlap consistence with the standard Hückel results. After the description of the two methods, test examples are used to show advantages and drawbacks
of the different approaches. In any case, the results are compared to the NBO-NRT
approach which is used on the electronic density obtained from standard DFT
hybrids calculations such as B3LYP/6-31+G(d). This chapter ends with an introduction to the HuLiS program in which the two methods are implemented.
This contribution is concerned with two approaches, called the Hückel-Lewis
(HuLiS) family of methods, that aim at associating a weight to a topological
envision of the electronic structure of a molecule. These methods are embedded in
the HuLiS code, which will also be briefly described. HuLiS targets primarily at a
classroom use, and is limited to planar p-conjugated systems. Our approach has
proved to be consistent with more elaborated methods such as the Natural Bond
Orbital (NBO)-based methods using Density Functional Theory (DFT) electronic
densities, or Valence Bond (VB) approaches [1]. It also has an appreciable
Y. Carissan (&) Á N. Goudard Á D. Hagebaum-Reignier Á S. Humbel
Aix Marseille Université, Centrale Marseille, CNRS, iSm2, UMR 7313,
13397 Marseille, France
e-mail: yannick.carissan@univ-amu.fr
N. Goudard
e-mail: nicolas.goudard@univ-amu.fr
D. Hagebaum-Reignier
e-mail: denis.hagebaum-reignier@univ-amu.fr
S. Humbel
e-mail: stephane.humbel@univ-amu.fr
© Springer International Publishing Switzerland 2016
R. Chauvin et al. (eds.), Applications of Topological Methods
in Molecular Chemistry, Challenges and Advances in Computational
Chemistry and Physics 22, DOI 10.1007/978-3-319-29022-5_13
337