Revealing ultrafast proton-transfer mediated autoionization as a source of low energy electrons in hydrogen-bonded systems

Journal Article · Thu Jan 01 00:00:00 UTC 2026 · Nature Communications

DOI: https://doi.org/10.1038/s41467-026-73415-3 · OSTI ID:3364776

Iskandar, Wael Iskandar ^[1]; Wang, Yi-Siang ^[2]; Suarez, Victor A ^[2]; Rohan, Matthew C ^[2]; Larsen, Kirk A ^[1]; Zhong Manis, James ^[2]; Severt, Travis Severt ^[3]; Williams, Joshua B. ^[4]; Ben-Itzhak, Itzik ^[3]; Orlando, Thomas M  ^[2]; Kretchmer, Joshua ^[2]; Weber, Thorsten ^[1]

---

1. Lawrence Berkeley National Laboratory
2. Georgia Institute of Technology
3. J. R. Macdonald Laboratory
4. University of Nevada

This study combines theory and experiment to probe ultrafast relaxation and dissociation in water dimers following inner- and outer-valence photoionization. By tracking electron and nuclear motion simultaneously, we reveal competing fragmentation pathways that produce low-energy electrons, which are key agents in radiation-induced chemistry, including DNA damage. While low-energy electrons are known to arise via intermolecular Coulombic decay, here we identify a faster relaxation mechanism gated by proton transfer following inner-valence ionization, which we call proton-transfer-mediated autoionization.

• Research Organization: Georgia Tech Research Corporation; Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States)
• Sponsoring Organization: US Department of Energy; USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22); USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22), Chemical Sciences, Geosciences & Biosciences Division (SC-22.1); USDOE Office of Science (SC), Basic Energy Sciences (BES). Chemical Sciences, Geosciences & Biosciences Division (CSGB)
• Grant/Contract Number: AC02-05CH11231; FG02-02ER15337
• OSTI ID: 3364776
• Journal Information: Nature Communications, Journal Name: Nature Communications
• Country of Publication: United States
• Language: English