Quantum chemistry

Quantum chemistry is the application of quantum mechanics to chemical problems, for example, the description of the electrical behavior of atoms and molecules, and its effect on their reactivity. ( Quantum mechanical investigations of atoms are considered borderline between chemistry and physics, and is not necessarily associated with quantum chemistry. )

As one of the first, the hydrogen molecule has been quantum chemically analyzed and calculated, namely in 1927 by the German scientists Walter Heitler and Fritz London. The methods they developed was by the American chemists John C. Slater and Linus Pauling to Valence- Bond ( VB) - extended or Heitler - London - Slater -Pauling ( HLSP ) method. In it, the focus is put on the consideration of the pairwise interaction between atoms, it fits so well with the classical view of the chemical bond.

An alternative approach to the nature of chemical bonding was developed by Friedrich Hund and Robert S. Mulliken, describes the delocalized electrons in the form of mathematical functions. The as dog - Mulliken or widespread than Molecular orbital ( MO ) method called description is for the classic chemist less intuitive and still by far more common.

With both approaches predict material properties are possible on mathematical approximation methods.

The applicability of quantum chemistry in the form of computer calculations can be found under Computer chemistry.

Some advanced topics are:

  • The Born- Oppenheimer approximation
  • The Hartree- Fock method (SCF method ( SCF: self - consistent field ) )
  • The density functional theory.

In addition, the following persons for the development of quantum chemistry are important:

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