Understanding Eu 3+ emission by using 15N vibronic shifts

Hexanltritolanthanates provide a unique opportunity to investigate the energy-level structures and crystal field of the lanthanlde ion (Ln ³⁺) in T _h site symmetry, with 12-coordlnation to oxygen. However, the electronic spectra are mainly vibronic and particularly extensive and complex. Advantage may be taken of the high energy of NO ₂ ^- vibrations, using ¹⁵N substitution, In assigning the electronic emission spectra. These features form a fingerprint In less-congested spectral regions. The technique is demonstrated for the case of Ln = Eu, from the study of the ⁵D ₀ emission spectra © 2010 American Chemical Society.