1. Schrödinger equation for a molecule

The field of application of quantum methods has expanded considerably since the advent, in 1931, of Hückel's method restricted to the description of π electrons only in conjugated organic molecules.

Basically, the methods of quantum chemistry, based on the principles of quantum mechanics, are generally aimed at determining the wave function of the considered polyelectronic system, atom or molecule, by solving the corresponding Schrödinger equation