Optical absorption of angulon in metal halide perovskites

We theoretically study the optical absorption of an angulon in the metal halide perovskites (MHP) based on the improved Devreese-Huybrechts-Lemmens model, where the formation of quasiparticle angulon states originates from the organic cation rotating in the inorganic octahedral cage of MHP. We find that the resonance optical absorption peaks appear when the energy of the incident photon matches the quantum levels of angulon. Moreover, the intensity of absorption depends on the quantum states of phonon angular momentum. These theoretical results provide significant insight to study the redistribution of angular momenta for the rotating molecules immersed in the many-body environment.