Intermolecular Coulombic decay in liquid water competes with proton transfer and non-adiabatic relaxation.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 40695787.
- Also identified by DOI 10.1038/s41467-025-61912-w and PMC identifier 12284144.
- No licence information is recorded for this record.
- Because redistribution is not established, this page shows the abstract only. Follow the links below for the full text.
Abstract
Despite decades of research, our understanding of radiation damage in aqueous systems remains limited. The recent discovery of Intermolecular Coulombic Decay (ICD) following inner-valence ionization of liquid water raises interesting questions about its efficiency as a major source of low-energy electrons responsible for radiation damage. To investigate, we performed electron-electron coincidence measurements on liquid H<sub>2</sub>O and D<sub>2</sub>O using a monochromatized high-harmonic-generation light source, detecting ICD electrons in coincidence with photoelectrons from the 2a<sub>1</sub> shell. We find that the ICD efficiency γ is below unity in both liquids and that γ(H<sub>2</sub>O)/γ(D<sub>2</sub>O) = 0.86 ± 0.03. Ab initio calculations reveal that ICD competes with proton transfer and non-adiabatic relaxation, which can close the ICD channel. A multi-scale stochastic model incorporating solvent effects reproduces these efficiencies. Our combined experimental and theoretical results suggest that the higher ICD efficiency in D<sub>2</sub>O arises from slower proton transfer and non-adiabatic transitions, highlighting the crucial role of nuclear motion in liquid-phase ICD and advancing the understanding of radiation damage.