Can solid-state effects enhance the cold-fusion rate?

Recently two groups have reported finding experimental evidence for an unexpectedly high rate of nuclear fusion at room temperature during the process of electrolytic deposition of deuterium on palladium and titanium. To achieve the rate of neutron production (∼10-23s-1 per deuteron pair) requires the solid-state environment to produce either an unusual enhancement of the fusion reaction rate or a large suppression of the Coulomb barrier between deuterons. The latter would presumably arise from some kind of sophisticated many-body screening effect in Pd or Ti, perhaps associated with quasiparticles of large effective mass2. Here we point out that within the framework of the lowest-order Born-Oppenheimer approximation, a very severe constraint is imposed on all such screening mechanisms in solids in equilibrium by the observable binding affinity of 4He atoms for the metal in question. Unless the latter is quite anomalous, the Coulomb barrier penetration in a solid in equilibrium cannot be enhanced anywhere near the magnitude required to explain the fusion rates inferred from the experiments. (author)