  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 are appeared when the energy of 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 rotational molecules immersed into the many-body
environment.
