AI and the World's Hard Problems · Chemistry & materials · arXiv · 2026-10-26
Unifying Low-Frequency Raman and Infrared Signatures across Perovskites
Perovskites share strong lattice anharmonicity, which shapes their low-frequency vibrational response, yet infrared and Raman signatures have usually been studied separately. The authors used machine-learning-based molecular dynamics to simulate IR and Raman spectra of oxide, halide, and double halide perovskites. Polar off-centering enhanced low-frequency IR and dielectric responses, while nonpolar modes such as octahedral tilting were linked to Raman central peaks. Slow polar reorientations shifted the dielectric response to very low frequencies, and overdamped tilting modes produced persistent Raman central peaks.