An accurate model-potential description of the valence spectrum of Ca

A modified effective potential for an valence-electron - -core interaction is shown to substantially improve the accuracy of calculated energies for Ca terms containing significant components, while maintaining high accuracy for other terms. In fact, we obtain near spectroscopic precision for those series which have little 3d character. Our calculations support the assignments of some 4s n g levels recently identified in the solar spectrum and, in particular, we confirm that lies below . The energy of the unidentified calcium term is predicted.