Third-order many-body perturbation theory calculations for the beryllium and magnesium isoelectronic sequences

Third-order many-body perturbation theory calculations for the beryllium and magnesium isoelectronic sequences

Relativistic third-order MBPT is applied to obtain energies of ions with two valence electrons in the no virtual-pair approximation (NVPA). A total of 302 third-order Goldstone diagrams are organized into 12 one-body and 23 two-body terms. Only third-order two-body terms and diagrams are presented here, owing to the fact that the one-body terms are identical to the previously studied third-orde...

Third-order many-body perturbation theory applied to Kondo-type dynamics in diluted magnetic semiconductors

One- and two-body densities for the beryllium isoelectronic series

Oneand two-body densities in position space have been calculated for the atomic beryllium isoelectronic series starting from explicitly correlated multideterminant wave functions. The effects of electronic correlations have been systematically studied by comparing the correlated results with the corresponding Hartree–Fock ones. Some expectation values such as ^d(r)&, ^r& , ^d(r12)& , ^r12 n &, ...

Finite-temperature second-order many-body perturbation theory revisited

We present an algebraic, nondiagrammatic derivation of finite-temperature second-order many-body perturbation theory [FT-MBPT(2)], using techniques and concepts accessible to theoretical chemical physicists. We give explicit expressions not just for the grand potential but particularly for the mean energy of an interacting many-electron system. The framework presented is suitable for computing ...

Many-Body Perturbation Theory: The GW Approximation

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