LCAO approximation - LCAO approximation

...Therefore, the hydrogen molecule _H2 has a total of two extranuclear electrons, but in the molecular orbital theory, these electrons are considered to be in the molecular orbitals that extend around the two hydrogen nuclei. There are various theoretical methods for calculating molecular orbitals specifically, but the most commonly used approximation is the method of expressing the molecular orbital as a linear combination of atomic orbitals, which is called the LCAO approximation (LCAO stands for linear combination of atomic orbitals). If the two hydrogen atoms that make up a hydrogen molecule are labeled a and b, and their 1s orbitals are represented as φ _a and φ _b , the molecular orbital according to the LCAO approximation can be expressed as follows: ...

*Some of the terminology that refers to the "LCAO approximation" is listed below.

Source | Heibonsha World Encyclopedia 2nd Edition | Information

…したがって，水素分子H₂は合計2個の核外電子をもつことになるが，分子軌道法では，2個の水素原子核の周囲に広がった分子軌道にそれらの電子がはいっているものと考える。　分子軌道を具体的に計算するには，いろいろな理論的手法があるが，最も普通に用いられる近似は，原子軌道の1次結合で分子軌道を表す手法であり，これをLCAO近似という(LCAOはlinear combination of atomic orbitalsの略)。水素分子を構成する2個の水素原子をそれぞれa,bと符号をつけて，そのおのおのの1s軌道をφ_a，φ_bと表すと，LCAO近似による分子軌道は，と表現できる。…

※「LCAO 近似」について言及している用語解説の一部を掲載しています。

出典｜株式会社平凡社世界大百科事典 第２版について | 情報