Palladium when it loads deuterium above 95% forms Fukai structures. Fukai structures are stable even
if the palladium is de-loaded. Loading above 95% is a requirement for excess heat in the Pons-Fleischmann experiment.
Fukai structures create large gaps in the lattice, some 18% vacancies which are called
superabundant vacancies (SAV). These vacancies form pores some 20 - 30 nm in size.
Deuterium exists in three states in palladium, as a D2 molecule, as a sigma bonded dihydrogen
molecule with Pd (van der waals attraction), and as a D+ ion sharing the electrons
with the palladium atoms in the lattice. The deuteriums' state depends on the background
electron density at its location. Deuterium in the Fukai pore areas may exist in
all three states.
There is also a notion that deuteron flux is a supporting element of cold fusion.
Peter Hagelstein's Lecture at MIT IAP Tuesday, Jan 28 at 1 hour 53 minutes had a slide
that mentions a cage effect. He did not talk about it however. I presume the cage
effect would apply to the interstitial D+ in a vacancy?
I am putting this out looking for more information about a cage effect possibly in Fukai structures.