Direct ab-initio calculation of ground-state electron densities and energies of atoms and molecules through a single, time-dependent hydrodynamical equation

Abstract

By using an imaginary-time evolution technique, coupled with the minimization of an expectation value, ground-state electron densities and energies have been directly calculated for six atomic and molecular systems (He, Be⁺⁺, Ne, H₂, HeH⁺, He₂⁺⁺), from a single time-dependent (TD) quantum fluid dynamical equation of motion whose real-time solution yields the TD electron density. For all the systems, a local Wigner-type correlation functional has been employed. For Ne, a local exchange functional is used while, for all the other systems, the exchange energy is calculated exactly. The static (ground-state) results are of beyond-Hartree-Fock quality for all the species.