An Eley-Rideal reaction takes place when a gas-phase particle reacts with another particle adsorbed onto a substrate. Eley-Rideal reactivity varies widely from system to system.  For example, the probability for H atom recombination is small on metals, while it is large on graphite.  Our paper is highly cited because it successfully explains this variation in reactivity in terms of a few simple ideas. In addition, H atom recombination on the graphitic surfaces of interstellar dust grains is currently a "hot" topic in astrophysics.

  Does it describe a new discovery or new methodology that's useful to others?

The vast amounts of molecular hydrogen existing in interstellar space are believed to have formed when H atoms collide and combine with other H atoms adsorbed onto dust grains.

We have demonstrated that this mechanism for molecular hydrogen formation is highly efficient when the interaction of the H atoms with the substrate (the dust grain, in this case) is relatively weak. Thus, molecular hydrogen formation on graphitic dust grains, where the H-graphite attraction is weak, should be highly probable.