In this section we will cover general aspects of electronic structure theory calculations.
Orbitals and basis sets
An introduction to wave functions for single-electron systems is given.
An introduction to many-electron wave functions is given.
Operators and matrix elements
An introduction to one- and two-electron operators is given together with a presentation of their associated matrix elements.
Definitions of spin operators and a visual illustration of collinear and noncollinear spin densities.
A presentation of a technique to transform integrals in the AO basis to the MO basis as needed for correlated wave function methods.
Definitions of correlation energy and a visual exploration of the effects of electron correlation on one- and two-particle densities.
Rayleigh–Schrödinger perturbation theory
A presentation of the perturbation theory in a form useful for Møller–Plesset methods.
A presentation of the occupation number formalism is given.