Accurate oscillator strengths for ²P - ²S transitions in neutral boron

We report benchmark calculations for the ground state and 18 lowest bound excited ²S and ²P states of the boron atom performed in the framework of the variational method. The wave functions were expanded in terms of all-particle explicitly correlated gaussian basis sets, while the Hamiltonian included a finite nuclear mass. These highly accurate, isotope-dependent, nonrelativistic wave functions were used to compute the transition dipole moments and the corresponding oscillator strengths in both length and velocity gauge for all allowed transitions between the considered states. Some of these quantities have not been reported in the literature before, while for others we improved the accuracy by several orders of magnitude. Moreover, the explicit mass dependence in our wave functions allowed us to identify several transitions where, in relative terms, the isotopic shift between ¹⁰B and ¹¹B in the oscillator strength values should be most significant.