Hydrophobic Hydrogen atoms are easily generated in water by the action of ionizing radiation, and can be detected in electron pulse radiolysis experiments with time-resolved electron paramagnetic resonance. The hyperfine coupling of the H atom in water lies slightly below the vacuum value, and exhibits a minimum at 240 degrees C. We can qualitatively explain this in terms of (a) the compression of the ground state 1s wavefunction by the surrounding water, and (b) distortion of the wavefunction when the atom collides with water molecules. Calculations (solid and dashed lines) based on two independent binary collision models overlay the data in the figure.  Data will also be presented regarding the diffusion of the atoms, and the chemically induced dynamic electron polarization (CIDEP) generated in their recombination reaction. Both H/D atom and H2O/D2O solvent isotope effects are seen in these experiments, which are inherently quantum mechanical in nature. Ring-Polymer Molecular Dynamic (RPMD) simulations using a quantized water model will be presented to interpret the hydrophobic solvation phenomena, both static and dynamic.

Temperature dependent solvation of the hydrogen atom in water

246th National Meeting (2013)

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