4 fⁿ-4 f^{n - 1} 5 d Transitions

This chapter describes the extension of the parametric model used for 4fn spectra to calculations of absorption and emission spectra for the 4fn−15d configuration. It illustrates their applications to calculate other properties of interest and examines the relationship between parametrized calculations and other approaches. The parametrized models are used to calculate the energy levels of the 4fn and 4fn−15d configurations of lanthanide ions in condensed-matter environments. The radiative and non-radiative transitions between these configurations are addressed in the chapter. Using these models, it is possible to explain the major features of the ultraviolet (UV), and vacuum ultraviolet (VUV) spectra for ions across the entire lanthanide series. Though ab initio calculations continue to improve and may take a larger role in the future, they are not expected to totally supersede parametrized models. Parametrized models, thus, provide valuable insights into electronic structure and spectra, and provide an efficient way of dealing with a variety of interesting optical properties in a large number of materials.