Unraveling the Relaxation Dynamics of Uracil: Insights from Time-Resolved X-ray Photoelectron Spectroscopy.

ABSTRACT: We report a study of the electronic and nuclear relaxation dynamics of the photoexcited RNA base uracil in the gas phase using time-resolved core-level photoelectron spectroscopy together with high-level calculations. The dynamics was investigated by trajectory surface hopping calculations, and the core ionization energies were calculated for geometries sampled from these. The molecule was excited by a UV laser and dynamics probed on the oxygen, nitrogen, and carbon sites by core electron spectroscopy. We find that the main de-excitation channel of the initially excited S₂(ππ*) state involves internal conversion to the S₁(nπ*) state with a time constant of 17 ± 4 fs, while a portion of S₂(ππ*) population returns directly to the ground state by internal conv

SUBMITTER: Facciala D 

PROVIDER: S-EPMC12395411 | biostudies-literature | 2025 Aug

REPOSITORIES: biostudies-literature