Energy levels and the oscillator strengths of the Be atom determined by a configuration-interaction calculation with a finite basis set fromBsplines

The simple configuration-interaction calculational procedure for an alkaline-earth atom is extended to include the continuum contribution to the Hamiltonian matrix evaluated in a basis set constructed from a quasicomplete set of discrete one-particle orbitals expanded in terms of a set of B splines. The procedure is successfully applied to the study of the energy eigenvalues, the excitation energies, and the oscillator strengths for transitions between selected ${}_{}{}^1{}_{}{}^{}$,3S, ${}_{}{}^1{}_{}{}^{}$,3P, and ${}_{}{}^1{}_{}{}^{}$,3D states of the beryllium atom. In addition to the simplicity of this calculational procedure and its effectiveness in generating atomic spectroscopy data for an extended spectral region in a single calculation with a single basis set, our numerical results have shown that the quantitative reliability of this procedure is comparable to or better than many other more elaborate theoretical approaches.