Advanced multiconfiguration methods for complex atoms: I. Energies and wave functions

Multiconfiguration wave function expansions combined with configuration interaction methods a method of choice for complex atoms where atomic state functions are expanded in a basis configuration state functions. Combined with a variational method such as the Hartree–Fock (MCHF) or multiconfiguration Dirac–Hartree–Fock (MCDHF), the associated set of radial functions can be optimized for the levels of interest. The review updates the variational MCHF theory to include MCDHF, describes the single and double process for generating expansions and the systematic procedure a computational scheme for monitoring convergence. It focuses on the calculations of energies wave functions from which other atomic properties can be predicted such as transition rates, structures and isotope shifts, for example.