Dissociative adsorption family doesn't do molecular oxygen [O][O]

[rwest]

Because O2 is Oj-Oj (bi-radical) it doesn't react according to the family,
and if not included in a reactionLibrary, it'll not happen.

We think probably it should be in a reactionLibrary, as a special case, but we'd need to figure out a way to make the rate work across a range of different metal surfaces.

[rwest]

@ehermes points out that perhaps more rigorous is to represent it as a vdW physisorption followed by a dissociation.

However, for now, getting it to react somehow is more important. There exist parameters for the one-step dissociative adsorption.

[ehermes]

For catalysts like Pt, adsorption of molecular O2 is not physisorption -- there is a chemical bond there.