Picosecond Lifetimes\nof Hydrogen Bonds in the Halide\nPerovskite CH<sub>3</sub>NH<sub>3</sub>PbBr<sub>3</sub>

The structures and properties of organic–inorganic\nperovskites\nare influenced by the hydrogen bonding between the organic cations\nand the inorganic octahedral networks. This study explores the dynamics\nof hydrogen bonds in CH<sub>3</sub>NH<sub>3</sub>PbBr<sub>3</sub> across\na temperature range from 70 to 350 K, using molecular dynamics simulations\nwith machine-learning force fields. The results indicate that the\nlifetime of hydrogen bonds decreases with increasing temperature from\n7.6 ps (70 K) to 0.16 ps (350 K), exhibiting Arrhenius-type behavior.\nThe geometric conditions for hydrogen bonding, which include bond\nlengths and angles, maintain consistency across the full temperature\nrange. The relevance of hydrogen bonds for the vibrational states\nof the material is also evidenced through a detailed analysis of the\nvibrational power spectra, demonstrating their significant effect\non the physical properties for this class of perovskites.