Gregory Hunt opened a general discussion of the papers by Anton Kokalj, Angelos Michaelides, and Christopher Taylor: Can you comment on how you apply DFT to non-aqueous systems (hydrocarbons)? How does the non-aqueous system inuence the surface corrosion mechanism?Angelos Michaelides answered: The application of a solvent to DFT can be done by co-adsorbing a very thin lm of e.g. hydrocarbons on top of the slab and running molecular dynamics simulations. This is the so-called ab initio molecular dynamics approach. 1 We have carried out many ab initio molecular dynamics studies of solid-liquid interfaces, e.g. ref. 2 and ref. 3. Although these two papers cited deal with water/solid interfaces, the same approach can in principle be applied to liquid hydrocarbon/solid interfaces. The main and very important drawback with these approaches is their enormous computational cost and if we were to consider the solvent we wouldn't have been able to perform such an extensive set of simulations of different adsorption structures as we have shown in our paper. For complex systems like the one considered here it is probably more appropriate to study a hydrocarbon solvent with a classical method, since good parameterised force elds exist for hydrocarbon molecules. responded: Technically the treatment of aqueous or nonaqueous solvents is similar. This implies that non-aqueous systems can be and have been studied using DFT methods. However, I have no experience with nonaqueous systems, hence I cannot comment on your second question.This journal is
Philippe Marcus asked: If the defects are neutral, one would expect no effect of the electric eld on oxide growth. Is this what you suggest?Mira Todorova responded: This is a very interesting suggestion to experimentally verify the existence/presence of charge neutral defects. We have not considered this aspect in our paper but would like to call for corresponding experiments in the region of phase space where such defects are predicted to be thermodynamically stable.Hendrik Bluhm questioned: Have you considered the presence of a hydroxide phase at the interface between ZnO and water? How would the presence of the hydroxide phase inuence your model on the role of point defects in governing the growth/dissolution of the oxide formed on Zn?Mira Todorova answered: A hydroxide phase at the interface was not considered. We chose ZnO for two reasons: (i) because of the availability of a vast amount of relevant data found for ZnO in the semiconductor literature and (ii) because ZnO is mentioned in the experimental literature on corrosion, as being the rst compact oxide layer formed during corrosion on ZnO. 1 The methodology presented in our work can be equally well applied to a hydroxide phase. Unfortunately, to our knowledge the information about the point defects forming in a Zn-hydroxide, which is needed for our thermodynamic model, is not available in the literature yet. Once we have performed the necessary density-functional theory calculations for the point defects in the hydroxide phase, the presence of the hydroxide phase can be explicitly considered.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.