biostudies-literatureUnknown10(48)Shah YTime-resolved optical Kerr effect (OKE) spectroscopy was employed to investigate the low-frequency vibrational dynamics of aqueous acetate solutions. While the isotropic OKE spectrum of neat water is broad and featureless, acetate solutions display a distinct band near 200 cm^-1. This feature increases systematically with acetate concentration, is absent in methyl acetate, and shows negligible dependence on the countercation, establishing it as the vibrational fingerprint of acetate-water hydrogen bonds. Comparison with hydroxide solutions demonstrates that the band is spectrally distinct from other anion-water vibrations. Quantum-chemical calculations further support the assignment, reproducing polarized vibrational modes in the same frequency region. Together, these results resolve long-standing ambiguities in the interpretation of acetate hydration and highlight the power of ultrafast OKE spectroscopy to isolate solute-specific hydrogen-bond vibrations in aqueous solutions. Beyond spectroscopy, these findings have implications for understanding electrolyte behavior in energy storage systems (e.g., lithium-ion batteries) and biological buffering processes.ACS omega59840-59848https://www.ebi.ac.uk/biostudies/studies/S-EPMC12772401biostudies-literatureUltrafast Optical Kerr Effect Spectroscopy Reveals the Vibrational Fingerprint of Acetate-Water Hydrogen Bonds.PMC12772401Meech SRHeisler IAShah YfalseUltrafast Optical Kerr Effect Spectroscopy Reveals the Vibrational Fingerprint of Acetate-Water Hydrogen Bonds.Time-resolved optical Kerr effect (OKE) spectroscopy was employed to investigate the low-frequency vibrational dynamics of aqueous acetate solutions. While the isotropic OKE spectrum of neat water is broad and featureless, acetate solutions display a distinct band near 200 cm^-1. This feature increases systematically with acetate concentration, is absent in methyl acetate, and shows negligible dependence on the countercation, establishing it as the vibrational fingerprint of acetate-water hydrogen bonds. Comparison with hydroxide solutions demonstrates that the band is spectrally distinct from other anion-water vibrations. Quantum-chemical calculations further support the assignment, reproducing polarized vibrational modes in the same frequency region. Together, these results resolve long-standing ambiguities in the interpretation of acetate hydration and highlight the power of ultrafast OKE spectroscopy to isolate solute-specific hydrogen-bond vibrations in aqueous solutions. Beyond spectroscopy, these findings have implications for understanding electrolyte behavior in energy storage systems (e.g., lithium-ion batteries) and biological buffering processes.2025-01-01T00:00:00Z2025 Dec2026-06-06T13:01:45.309Z2026-05-30T03:11:16.958ZS-EPMC127724014150271710.1021/acsomega.5c09879