Spin-Coupled Generalized Valence Bond Theory: An Appealing Orbital Theory of the Electronic Structure of Atoms and Molecules

Dunning, Thom H.; Xu, Lü; Karadakov, Peter B.

doi:10.1016/b978-0-12-821978-2.00017-9

Cited by 1 publication

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“…The Rumer set shown in Scheme b does not follow rotation about this Y axis and, thus, does not follow the corresponding C 2 v symmetry. Permutation of the orbitals, as mentioned earlier (see, e.g., ref ), results in new sets, some of which may follow the C 2 v symmetry. Scheme e displays the most intuitive Rumer set that follows this C 2 v symmetry, obtained by reordering the orbitals (other possible Rumer sets that follow the symmetry involve crossing of the bonds and are therefore less intuitive; see Scheme S2 in Supporting Information).…”

Section: Resultsmentioning

confidence: 73%

New Methodology to Produce Sets of Valence Bond Structures with Enhanced Chemical Insights

Roy

Shurki

2023

J. Chem. Theory Comput.

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The valence bond (VB) theory uses localized orbitals, and its wave function is composed of a linear combination of various VB structures which are based on sets of spin functions. The VB structures are not unique, and different sets are used, Rumer sets being the most common for classical VB due to their advantage as being both easily obtained as linearly independent and meaningful. Yet, Rumer rules, which are responsible for the simplified process of obtaining the Rumer sets, are very restrictive. Furthermore, Rumer sets are best suited for cyclic systems; however, in noncyclic systems, structures resulting from Rumer rules are often not the most intuitive/suitable structures for these systems. We have developed a method to obtain chemically insightful structures, which is based on concepts of chemical bonding. The method provides sets of VB structures with improved chemical insight, which can also be controlled. Parallel to the Rumer structures, the chemical insight sets of structures are based on electron pair coupling, and hence, pictorially can be drawn similarly to the Lewis structures. Yet, different from Rumer rules, the chemical insight method, being more flexible, allows larger combinations of bonds as well as larger combinations of structures in the sets it offers, resulting in many more possible sets that are better adapted to the systems studied.

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Section: Resultsmentioning

confidence: 73%