Absorption spectrum of CfCl3

Abstract

The absorption spectrum of thin films of CfCl₃ was measured at 298, 77, and 4°K in the range 6000–46 000 cm⁻¹. Interpretation of the results was based on systematic variation of energy level parameters over the actinide series. Electrostatic, spin‐orbit, and configuration interaction terms were calculated by diagonalization of the complete interaction matrices and a least squares fitting process involving 27‐level assignments. Compared to the energies of the first $\mathrm{f\to \; d}$ transitions observed in lighter actinide trichlorides, the corresponding band in CfCl₃ appears to occur at an anomalously low energy.