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

TY - CHAP

T1 - Spin-Coupled Generalized Valence Bond Theory

T2 - An Appealing Orbital Theory of the Electronic Structure of Atoms and Molecules

AU - Dunning, Thom H.

AU - Cooper, David L.

AU - Xu, Lu T.

AU - Karadakov, Peter B.

N1 - Publisher Copyright: © 2023 Elsevier Inc. All rights reserved.

PY - 2023/1/1

Y1 - 2023/1/1

N2 - This Chapter outlines the basic elements of Spin-Coupled Generalized Valence Bond (SCGVB) theory, including the structure of the SCGVB wavefunction and its optimization and analysis. The SCGVB wavefunction accounts for non-dynamical electron correlation, yet still provides a compelling orbital description of the electronic structures of the ground and excited states of molecules and of the electronic mechanisms of chemical reactions. The insights provided by SCGVB theory are illustrated using a representative set of examples: the “traditional” HCN molecule, and its fragmentation into CH and N; the formation of “hypervalent” SF4 and SF6 from SF n-1 + F; resonance/antiresonance in benzene and C7H7+; the excited states of benzene, CH and O3/SO2; and the reaction of ground state methylene with H2. The effects of dynamical electron correlation, which must be included to make quantitative predictions of molecular properties, can be taken into account by using the SCGVB wavefunction expressed in natural orbitals as the reference wavefunction in traditional multireference configuration interaction calculations.

AB - This Chapter outlines the basic elements of Spin-Coupled Generalized Valence Bond (SCGVB) theory, including the structure of the SCGVB wavefunction and its optimization and analysis. The SCGVB wavefunction accounts for non-dynamical electron correlation, yet still provides a compelling orbital description of the electronic structures of the ground and excited states of molecules and of the electronic mechanisms of chemical reactions. The insights provided by SCGVB theory are illustrated using a representative set of examples: the “traditional” HCN molecule, and its fragmentation into CH and N; the formation of “hypervalent” SF4 and SF6 from SF n-1 + F; resonance/antiresonance in benzene and C7H7+; the excited states of benzene, CH and O3/SO2; and the reaction of ground state methylene with H2. The effects of dynamical electron correlation, which must be included to make quantitative predictions of molecular properties, can be taken into account by using the SCGVB wavefunction expressed in natural orbitals as the reference wavefunction in traditional multireference configuration interaction calculations.

KW - Antiresonance/Antiaromaticity

KW - Atomic and Molecular electronic structure

KW - Chemical bonding

KW - Chemical reactions

KW - Covalent bond

KW - Dynamical electron correlation

KW - Excited states

KW - Non-dynamical electron correlation

KW - Potential energy curves

KW - Potential energy surfaces

KW - Recoupled pair bond

KW - Recoupled pair bond dyad

KW - Resonance/Aromaticity

KW - Spin-Coupled Generalized Valence Bond (SCGVB) theory

UR - http://www.scopus.com/inward/record.url?scp=85191891107&partnerID=8YFLogxK

U2 - 10.26434/chemrxiv-2022-lxrzw-v2

DO - 10.26434/chemrxiv-2022-lxrzw-v2

M3 - Chapter

AN - SCOPUS:85191891107

VL - 1

SP - V1-354-V1-402

BT - Elsevier’s Major Reference Work on Comprehensive Computational Chemistry, Valence Bond (VB) Theory and Related Approaches

A2 - Shaik, Sason

A2 - Hiberty, Phillipe

PB - Elsevier

ER -