Study of Interfacial Proton Transport

In these calculations, valence electrons are represented by double- augmented Gaussian basis sets (DZVP-MOLOPT) (VandeVondele and Hutter, 2007). The 

FIGURE 2.34 Inteifacial configuration considered in studies of proton transport mechanisms. Donor (D), acceptor (A), and spectator (S) SGs are indicated. The collective variable dev = d 2 — d23 is shown as well. 

The value of AFa for the collective transition is 2-3 times larger than the activation energy of proton transport in bulk water (0.1 eV), as expected, based on the increased hydrogen bond strength. It is to be seen in refinements of metadynamics simulations whether different choice of CVs and evaluation of longer SGs will reduce AFa significantly. 

Hydrogen bond breaking and reformation is responsible for the steep ascending and descending flanks of free energy along the CV. The H3O+ ion shift occurs in the 

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