Chapter 2 - Dyson orbitals and chemical bonding

Abstract

Descriptions of electrons in molecules that are experimentally verifiable and that generalize qualitatively useful concepts of uncorrelated, molecular-orbital theory to the exact limit of Schrödinger's time-independent equation are provided by Dyson orbitals, their probability factors, and their electron binding energies. Dyson orbitals may be understood as overlaps between initial, N-electron states and final states with N±1 electrons and are related to many kinds of transition intensities. They also may be used to construct electron densities, one-electron properties and total energies with formulae that include probability factors between zero and unity. Electron-propagator approximations expressed in the Dyson quasiparticle equation or superoperator secular equations provide direct determinations of Dyson orbitals and eliminate the need for many-electron wavefunctions of initial or final states. Applications to anionic clusters of hydrogen sulfide, relationships between superacids and superhalogens, and diffuse electron pairs that occur in double Rydberg anions and solvated electron precursors illustrate the interpretive advantages of Dyson-orbital concepts.