Electron binding energies from static linear response calculations

Electron binding energies are computed using a truncated Taylor series where the first-order corresponds to orbital energies. Higher-order corrections are obtained from perturbation theory where the perturbation corresponds to a sudden change on orbital occupations, e.g., changes on the total number of electrons of the system. Some connections to fractional charge calculations are discussed shortly but emphasis is made on practical application. Formulation is derived up to third-order based only on density linear response which for the case of frontier orbitals is the electronic Fukui function. Electronic ionizations and double ionizations were computed and compared to Green's function methodologies. Second-order approximation is already an accurate choice but in some cases higher order is required.

Automated summary

Electron binding energies are calculated using a truncated Taylor series and perturbation theory, with emphasis on practical applications. The formulation is derived up to third-order based on density linear response, particularly for frontier orbitals. Second-order approximation is accurate in most cases, but higher order may be required in some instances.