A minimalistic approach to broad band emission modeling, and automated configurational diagram construction

Abstract

In this paper, we propose a novel approach to broad emission band modeling. The ground state and the excited state of the emitter are represented as two continuous parabolic manifolds, where energy is proportional to the square of a certain geometrical coordinate (E = kx²). The emitting level population is described by Boltzmann distribution, with absolute temperature as a parameter. Depending on the offset between the two parabolas and their curvatures (force constants) both symmetric and asymmetric Gaussian-like band shapes can be produced. Also proposed is a simple algebra that maps the input energy axis values of the experimental spectrum to the values of the geometrical (configurational) coordinate. The resulting band shape can be compared to the experimental one via least-squares fitting of the model parameters. Its usefulness in spectrum decomposition (deconvolution) is demonstrated using a few examples (doped inorganic phosphors; d–d, f–d and charge transfer transitions). Presence of absolute temperature in the definition of the model provides a potential for its use in primary luminescence thermometry.