A limited multiconfiguration frozen-core approximation for atoms: Some results for the boron isoelectronic sequence

The formalism of the frozen-core variant of the Hartree-Fock approximation for atoms has been extended to some states which are inadequately described by means of a single electronic configuration. Different possible choices of the core orbitals have been considered, and calculations performed in the particular case of the boron isoelectronic sequence. A large number of s-p and p-d dipole oscillator strengths have been computed, with good results in most cases.