Measurement and interpretation of plutonium spectra

The atomic spectroscopic data available for plutonium are among the richest of any in the periodic system. They include high-resolution grating and Fourier-transform spectra as well as extensive Zeeman and isotope-shift studies. The present status of the term analysis is summarized, and the configurations that have been identified are cited. A least-squares adjustment of a parametric Hamiltonian for configurations of both Pu I and Pu II has shown that almost all of the expected low levels are now known. The use of a model Hamiltonian applicable to both lanthanide and actinide atomic species has been applied to the low configurations of Pu I and Pu II making use of trends predicted by ab initio calculations. This same model has been used to describe the energy levels of Pu3+ in LaCl3, and an extension has permitted preliminary calculations of the spectra of other valence states. 46 references, 9 figures, 7 tables