Herein, we present a methodology based on constrained density functional theory and vibrational mode computations to simulate and interpret the luminescence spectra of periodic solids. A multi-dimension harmonic model is used to combine electronic and vibrational contributions into an overall vibrationally resolved emission spectrum. We applied it to Ti-doped BaZrO₃ to accurately reproduce its blue luminescence and unambiguously assign the observed luminescence to a Ti³⁺ + O^- → Ti<…