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Updated: Jul 22, 2026

Proton Transfer and Protein Conformation Dynamics in Photosensitive Proteins by Time-resolved Step-scan Fourier-transform Infrared Spectroscopy
Published on: June 27, 2014
Real-time observation of bimodal proton transfer in acid-base pairs in water
Matteo Rini1, Ben-Zion Magnes, Ehud Pines
1Max Born Institut fuer Nichtlineare Optik und Kurzzeitspektroskopie, Max Born Strasse 2A, D-12489 Berlin, Germany.
Abstract:
The neutralization reaction between an acid and a base in water, triggered after optical excitation, was studied by femtosecond vibrational spectroscopy. Bimodal dynamics were observed. In hydrogen-bonded acid-base complexes, the proton transfer proceeds extremely fast (within 150 femtoseconds). In encounter pairs formed by diffusion of uncomplexed photoacid and base molecules, the reaction upon contact was an order of magnitude slower, in agreement with earlier reported values. These results call for a refinement of the traditional Eigen-Weller picture of acid-base reactions: A three-stage model is introduced to account for all observed dynamics.
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