Yes, specifically (p.5): The AEH provides a possible explanation for the varied effectiveness of the alpha, beta, and gamma phases of CF loading. I suggest that in the initial loading phase the adsorbed hydrogen is, as suggested by others, alternately in H and H+ form, but primarily in H+ form. It is primarily ionically bound to the lattice, especially when in motion. An H atom almost fits inside a tetrahedral lattice cell, but not through the triangular portals between cells. In the beta phase, many of the cells are occupied by H molecules, and in such a state, diffusion between cells requires displacement of some H molecules, the diffusion paths tend to be blocked, and the continued diffusion requires the ionization of a path blocking H or its tunneling out of the way. Some degree of H confinement upon the reconversion from an H+ to H would occur, thus some small AE excess energy might be produced in beta phase. In the gamma phase, H loading would be to the point that additional loading would force the formation of H2 molecules in the tetrahedral sites and in the face holes. In looking at the geometry of the Ni lattice and H2 molecules, it appears such a formation is possible with only a deformation of the lattice of about 2 percent. This would, however, imply extreme confinement and local pressure, which would dramatically increase the work done by ZPE in supporting the H2 formation, or "expansion".
Thanks! Terry On Mon, Oct 26, 2009 at 12:46 AM, Horace Heffner <[email protected]> wrote: > > I am sorry to say my memory is just not very good so I'm not sure what you > mean. > > I did some basic lattice computations here: > > http://mtaonline.net/~hheffner/AtomicExpansion.pdf > > Summarized here as compared to the Cubic Close Packed Structure using bond > lengths provided from webelements.com (at your request if I recall > correctly): > > http://www.mtaonline.net/~hheffner/CCP.pdf > > Best regards, > > Horace Heffner > http://www.mtaonline.net/~hheffner/ > > > > >
