Improvement of Electronic Structure Calculations for the Interpretation of the Emission Spectrum for Ndiii Complexes

A protocol to correct ab initio calculated luminescence spectra of NdIII complexes is proposed. The emission spectrum of [NdIII(bipy)(tta)<inf>3</inf>] was measured to calibrate the optimal correction for the Racah parameters on top of a CASSCF calculation to attain the best energetic placement of the 4F<inf>3/2</inf> → 4I<inf>13/2−9/2</inf> emission lines. As interelectronic repulsion is the most important source of error in this calculation, this straightforward correction results in an accurate placement of transitions, allowing the assignment of a complex spectral shape in terms of its underlying transitions. Finally, the correction derived for [NdIII(bipy)(tta)<inf>3</inf>] was directly applied to a different NdIII complex, demonstrating the broad use of this approach. © 2025 The Royal Society of Chemistry.