Excited State Absorption and Crystal Field Analysis of Lanthanide Ion Complexes

In order to exploit the optical properties of lanthanide ions it is necessary to understand their electronic energy levels. With this knowledge, schemes can be made for the efficient excitation of phosphors or of the energy transfer from one ion to another. At present, although the lower f-electron energy levels are well-studied and modeled, the higher 4fN and 4fN-15d energy levels remain less well-known because of experimental problems since the transitions to these levels lie in the vacuum ultraviolet region where spectral resolution is poor. The researchers can make an analogy of the energy levels to a long ladder. This study aims to investigate the upper part of the ladder not by starting at the bottom of the ladder, but by starting much higher up. Then the jump from start to finish is quite small so that the transitions between the energy levels are located in the visible spectral region. The spectral resolution is good and the detection of the spectra is much easier. The derived information from this project will not only catalogue the energy level systems of lanthanide ions but more importantly, it serves to test the current theories of energy level calculation. This is an integral part of the project.