Scientific Achievement
- Researchers in the Condensed Phase and Interfacial Molecular Science (CPIMS) program directly revealed stable inter-anionic hydrogen bonding in aqueous phosphoric acid using X-ray spectroscopy and theoretical analysis, identifying H₂PO₄⁻⋯H₂PO₄⁻ dimers that redefine ionic association in condensed phases
Significance and Impact
- Demonstrates that like-charged ions can stably hydrogen bond in water, overturning classical electrostatic assumptions and informing models of proton transport, solvation, and ion conduction in energy materials
Research Details
- The combined approach of X-ray absorption fine structure spectroscopy (EXAFS and NEXAFS) and electron-affinity time-dependent density functional theory (EA-TD-DFT) elucidates the angstrom-scale local hydrogen bonding environment of phosphate species in aqueous phosphoric acid. The formation of dimer is observed in concentrations higher than 6 M, which is stabilized by solvent screening and charge transfer via hydrogen bonding of water
Publication Details
P. Kim, R. Kang, K. Carter-Fenk, K. R. Wilson, M. Head-Gordon, M. Ahmed, Journal of the American Chemical Society (2025).
Work was performed at Lawrence Berkeley National Lab.
