On Fri, Nov 23, 2012 at 10:33 PM, <[email protected]> wrote: I think what he's trying to say is that a fast D nucleus can also knock an > inner > electron out of Pd, which can then in turn accelerate another D nucleus, > in a > train of reactions. >
I am reminded of a pinball machine, where the palladium atoms are the devices with the rubber bouncers that flip the ball across to the other side. Once you drop a pinball into the machine, it can go for quite a while before falling through the opening at the bottom. Another image that comes to mind is letting go of several marbles at the top of a board with nails nailed into it in a cross-hatch fashion. Maybe the cracks that Ed Storms draws our attention to facilitate something here -- in a perfect lattice, perhaps there is less occasion for movement of this kind, whereas it becomes more possible when there is a small amount of void for the D nuclei to bounce around in. In a noble gas, maybe the analogy would be that of letting a bull go in a china shop. ;) One question I have has to do with the energies. At 20 keV, would an incident D nucleus impart enough momentum to the palladium atom enough to unseat it from the surrounding lattice? If so, it does not seem like such an interaction could last for very long before the local region was altered significantly. Eric
