Proton transfer weak coupling case

Proton Transfer In the Case of Weak Coupling with the Medium... 

There have been a number of investigations of the formulation of the problem of electron transfer accompanied by atom transfer particularly with regard to the simultaneous movement of the proton (which, in view of its small mass, may in fact be an atypical case). A possible model for such processes would assume a conservation of bond order along the reaction coordinates (Johnston, 1960). It is of interest that the results of such calculations are similar to those for electron transfer for weak coupling, although the interpretation of the process and parameters (such as a) are different. 

As outlined in the Introduction, a couple of suggested pathways have been proposed for the first electron transfer step (a) dissociative chemisorption of O2 (rds) probably accompanied by e-transfer and followed by proton transfer (b) simultaneous proton and electron transfer to a weakly adsorbed O2 molecule. We have recently shown through CPMD [21,69] and DFT [75] results that both pathways may take place under different conditions of the interfadal structure i.e., proton transfer may be involved in the first reduction step depending on the relative location of the O2 molecule with respect to the surface and to the proton, on the degree of proton hydration, and on the surface charge which is dependent on the electrode potential. Moreover, it was shown that proton transfer may precede or follow the first electron transfer, but in most cases the final product of the first step is an adsorbed HOO. ... 

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