- Dynamics of water and hydrated protons in confinement
- Award date
- 28 October 2015
- Number of pages
- Document type
- PhD thesis
- Faculty of Science (FNWI)
- Van 't Hoff Institute for Molecular Sciences (HIMS)
In this thesis the dynamics of water and hydrated protons in confinement has been studied using nonlinear spectroscopy methods, including IR pump-probe spectroscopy and vibrational sum frequency generation spectroscopy (VSFG spectroscopy).
Using the IR pump-probe spectroscopy, we first investigated the structural and dynamical properties of the O-H vibrations of the proton hydration complexes in hydrated Nafion. We found a strong reorganization of the proton hydration structure following single-quantum excitation of a proton vibration with infrared pulses. While, the infrared induced proton transfer becomes less observable with the increase of hydration level due to the acceleration of the vibrational relaxation and the increasingly dominant influence of the heating effect that results from the vibrational relaxation. With same method, we also studied the vibrational relaxation of aqueous protons in hydrated water clusters formed in acetonitrile, the vibrational dynamics of the bending mode of hydrated protons in Nafion and the energy relaxation dynamics of the hydration complex of hydroxide.
With VSFG spectroscopy, we investigated the vibrational response of the hydration shells of hydrophobic anions (triflate, ethanesulfonate, and butanesulfonate). The addition of these hydrophobic anions mainly leads to a frequency shift of the main VSFG band for solution in H2O, while to a strong amplitude increase for solution in D2O. The difference is associated with a strong isotope effect in the intra- and intermolecular mixing of the hydroxyl stretch vibrations of the water molecules contained in the hydration shells of the hydrophobic anions.
- Research conducted at: Universiteit van Amsterdam