Green's function methods for calculating ionization potentials, electron affinities, and excitation energies

Green's function (GF; electron propagator) methods represent a very useful set of tools for direct calculation of electron detachment (ionization potentials), electron attachment (electron affinities), excitation energies, electron transition probabilities, and other properties. The main idea of GF methods is that for description of various properties of a many‐body system, one does not need to describe all the particles of the system but rather needs information about one or two particles belonging to the system. The corresponding required quantities are the one‐ and two‐particle GFs. Within one‐ or two‐particle GF methods, the energy difference between an initial state and a state with one additional or one less electron is calculated directly, thus eliminating errors due to inconsistent treatment of the initial and final states. © 2011 John Wiley & Sons, Ltd. WIREs Comput Mol Sci 2011 1 377–387 DOI: 10.1002/wcms.38 This article is categorized under: Electronic Structure Theory > Ab Initio Electronic Structure Methods