When dealing with the Kohn-Sham type of these, the expectation value of the kinetic energy operator is the non-interacting kinetic energy. The linear expansion in terms of Slater determinants of the Hartree-Fock type of these is known as Configuration Interaction. Koopman's Theorem relates the energy of these to ionization potential and electron affinity. A simpler theory of the way they work defines some as antibonding and others as nonbonding and utilizes the abbreviations LUMO and HOMO. This 
When dealing with the Kohn-Sham type of these, the expectation value of the kinetic energy operator is the non-interacting kinetic energy. The linear expansion in terms of Slater determinants of the Hartree-Fock type of these is known as Configuration Interaction. Koopman's Theorem relates the energy of these to ionization potential and electron affinity. A simpler theory of the way they work defines some as antibonding and others as nonbonding and utilizes the abbreviations LUMO and HOMO. This is the molecular type of, FTP, what chemical concept, which can describe the path that an electron takes in circling the nucleus.
When dealing with the Kohn-Sham type of these, the expectation value of the kinetic energy operator is the non-interacting kinetic energy.
molecular (or atomic) {orbital}s