Accurate Multiconfiguration Hartree-Fock Calculations of Oscillator Strengths in Light Atoms: The Boron (B ii) Line at 1362 Angstrom

A new method to deal with nonorthogonalities in transition calculations has been implemented and tested. Large-scale transition calculations using the multiconfiguration Hartree-Fock (MCHF) method have been performed for the resonance line of B II at 1362 Angstrom. In these calculations the orbital sets of the initial and final-state wavefunctions have not been assumed to be equal but have been optimized independently. The calculated weighted multiplet oscillator strength gf= 0.999 has an estimated uncertainty of less than 0.5%. Together with the previously calculated isotope shift and hyperfine structure (Jonsson, Johansson, and Froese Fischer 1994), all the important atomic parameters needed for a detailed modeling of the B II resonance line in high-resolution astrophysical spectra are now available with high accuracy