Quantum Chemistry

quantum chemistry is the application of the quantum Mécanique to the problems of the Chimie.

The description of the electronic behavior of the Atom S and the Molecule S to explain their reactivities is an application of quantum chemistry.

Short history

As the studies on quantum mechanics are regarded as being at the border between chemistry and physics, they thus do not form generally part of quantum chemistry, but what one regards as the first quantum calculation of chemistry was done by the German scientists Walter Heitler and Fritz London on the hydrogen molecule in 1927. The method of Heitler and London was extended to the the United States by the chemists John C. Slater and Linus Pauling to become the method “Valence-Jump (VB)” (or Heitler-London-Slater-Pauling (HLSP) ). In this method, the attention is especially related to the interaction of the electronic pairs, and it correlates rather well with the traditional manner of representation of the chemical bonds by the chemists.

In another approach developed by Friedrich Hund and Robert S. Mulliken, the electrons are described like mathematical functions delocalized on the entirety of the molecule. The approach of Hund-Mulliken , more commonly called method of the molecular orbital , even if it is shown less intuitive for the chemists, is that which makes it possible best to predict the properties of the molecules and is thus the method most used nowadays.

The equations of quantum chemistry becoming very quickly too complex to be solved exactly, it is current to make of it an approximate numerical resolution using supercomputers.

Models and approximations used in quantum chemistry

Methods of calculating

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Some scientists implied in the development of quantum chemistry:

See too

  • History of quantum chemistry

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