Method for describing the electronic structure of molecules using quantum mechanics
See also: Molecular orbital
Electronic structure methods
Valence bond theory
Coulson–Fischer theory Generalized valence bond Modern valence bond theory
Molecular orbital theory
Hartree–Fock method Semi-empirical quantum chemistry methods Møller–Plesset perturbation theory Configuration interaction Coupled cluster Multi-configurational self-consistent field Quantum chemistry composite methods Quantum Monte Carlo
Density functional theory
Time-dependent density functional theory Thomas–Fermi model Orbital-free density functional theory Linearized augmented-plane-wave method Projector augmented wave method
Electronic band structure
Nearly free electron model Tight binding Muffin-tin approximation k·p perturbation theory Empty lattice approximation GW approximation Korringa–Kohn–Rostoker method
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In chemistry, molecular orbital theory (MO theory or MOT) is a method for describing the electronic structure of molecules using quantum mechanics. It was proposed early in the 20th century.
In molecular orbital theory, electrons in a molecule are not assigned to individual chemical bonds between atoms, but are treated as moving under the influence of the atomic nuclei in the whole molecule.[1] Quantum mechanics describes the spatial and energetic properties of electrons as molecular orbitals that surround two or more atoms in a molecule and contain valence electrons between atoms.
Molecular orbital theory revolutionized the study of chemical bonding by approximating the states of bonded electrons—the molecular orbitals—as linear combinations of atomic orbitals (LCAO). These approximations are made by applying the density functional theory (DFT) or Hartree–Fock (HF) models to the Schrödinger equation.
Molecular orbital theory and valence bond theory are the foundational theories of quantum chemistry.
^Daintith, J. (2004). Oxford Dictionary of Chemistry. New York: Oxford University Press. ISBN 978-0-19-860918-6.
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In chemistry, molecularorbitaltheory (MO theory or MOT) is a method for describing the electronic structure of molecules using quantum mechanics. It...
region. The terms atomic orbital and molecularorbital were introduced by Robert S. Mulliken in 1932 to mean one-electron orbital wave functions. At an elementary...
In chemistry, valence bond (VB) theory is one of the two basic theories, along with molecularorbital (MO) theory, that were developed to use the methods...
are sometimes collectively called the frontier orbitals, such as in the frontier molecularorbitaltheory. The energy difference between the HOMO and LUMO...
In chemistry, orbital hybridisation (or hybridization) is the concept of mixing atomic orbitals to form new hybrid orbitals (with different energies,...
A molecularorbital diagram, or MO diagram, is a qualitative descriptive tool explaining chemical bonding in molecules in terms of molecularorbital theory...
molecular orbital explanations for chemical reactions. Bonding molecularorbital Valence and conduction bands Valence bond theoryMolecularorbitaltheory Conjugated...
chemistry, the bonding orbital is used in molecularorbital (MO) theory to describe the attractive interactions between the atomic orbitals of two or more atoms...
(Hartree–Fock) molecularorbitaltheory incorrectly predicts dissociation into a mixture of atoms and ions. On the other hand, simple molecularorbitaltheory correctly...
an application of molecularorbitaltheory to transition metal complexes. A transition metal ion has nine valence atomic orbitals - consisting of five...
theory are examples. More sophisticated theories are valence bond theory, which includes orbital hybridization and resonance, and molecularorbital theory...
models such as simple Lewis and VSEPR structure, valence bond theory, molecularorbitaltheory, isovalent hybridization, and Bent's rule are discussed below...
on a specific atom. They can be used to relate molecularorbital calculations to simple bonding theories, and also to speed up post-Hartree–Fock electronic...
In molecular physics, crystal field theory (CFT) describes the breaking of degeneracies of electron orbital states, usually d or f orbitals, due to a static...
energy 251 kJ/mol). Hückel molecularorbitaltheory offers another approach for defining bond orders based on molecularorbital coefficients, for planar...
delocalized over an entire molecule. The Hund–Mulliken approach or molecularorbital (MO) method is less intuitive to chemists, but has turned out capable...
combinations of either atomic orbitals, delocalized atomic orbitals (Coulson-Fischer theory), or even molecularorbital fragments. Although this is often...
According to the frontier molecularorbitaltheory, the sigma bond in the ring will open in such a way that the resulting p-orbitals will have the same symmetry...
qualitative molecularorbital, was proposed. The 3c-4e bond is described as three molecularorbitals given by the combination of a p atomic orbital on the...
influence molecular geometry and are said to be stereochemically inactive. In molecularorbitaltheory (fully delocalized canonical orbitals or localized...
The fragment molecularorbital method (FMO) is a computational method that can be used to calculate very large molecular systems with thousands of atoms...
orbitals) and pi bonds (formed by unhybridized p orbitals for atoms of main group elements). The geometry can also be understood by molecularorbital...
According to molecularorbitaltheory, the electron configuration of triplet oxygen has two electrons occupying two π molecularorbitals (MOs) of equal...
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