They can also be calculated by Self-Consistent Field theories.
These constructs can be omitted in Density Functional Theories in a uniqueness result named for Hohenberg and Kohn. Woodward and Hoffman used these constructs to predict stereo- and regio-selectivity of pericyclic reactions. Koopmans' theorem relates the energy of these constructs to ionization energy. In Hartree-Fock theory these are the (*) eigenfunctions of the Fock operator, and are linear combination of Gaussian functions. They can also be calculated by Self-Consistent Field theories. They can be used to calculate bond order, and these predict the paramagnetism of gaseous oxygen and the stability of radicals like nitric oxide. Their antibonding variety is usually denoted with an asterisk. For 10 points, name this extension of Lewis and VSEPR theory to multi-atom systems
These constructs can be omitted in Density Functional Theories in a uniqueness result named for Hohenberg and Kohn.
{Molecular Orbital} Theory [prompt on {MO}, prompt on {electron} "{orbital}" until mentioned]