Deuteron tunneling at electron-volt energies

We speculate on a new mechanism for deuteron-deuteron fusion reactions at electron-volt energies. Appealing to conservation principles, it is shown that deuteron tunneling leading to fusion is very unlikely to take place between two isolated deuterons. It is argued that in solids, however, tunneling may lead to fusion via a new reaction mechanism which populates energy levels of⁴He, with simultaneous energy transfer to an electron. Predictions of this theory are that d+d+e^– fusion at electron-volt energies in solids should lead to copious production of tritium, protium, energetic electrons, and small quantities of⁴He.