Regensburg 2019 – wissenschaftliches Programm

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BP: Fachverband Biologische Physik

BP 9: Computational biophysics

BP 9.10: Vortrag

Dienstag, 2. April 2019, 12:15–12:30, H11

Decompostion of the proton transfer dynamics in the Zundel cation — •Florian N. Brünig and Roland R. Netz — Institut für Theoretische Physik, Freie Universität Berlin

Although extensively studied in experiment and theory, the dynamics of excess protons in water and in particular the proton transfer between molecules remain elusive. The direct intermediate of the proton transfer in water is indisputably the H₂O₅⁺ or Zundel cation, which has recently been studied experimentally by infrared spectroscopy. The experiments have been interpreted in terms of a low-barrier double-well potential for the excess proton caused by the two adjacent water molecules. We investigate the proton transfer mode by ab-initio simulations of a single Zundel cation and decomposition techniques. We compare calculated spectra with analytic theory that predicts a low frequency spectral tail due to barrier-crossing events. The fast exchange dynamics produces a high-frequency spectral contribution that can be interpreted using a one-dimensional generalized Langevin equation.