I've worked out a simple model, and here are some reactions: $ python scripts/reactions.py "Li+Cu, Li+Fe, Li+Ni, d+Cu, d+Fe, d+Ni, d+Li" --model pion-exchange d + 61Ni → 2·p + 62Ni + 1082 keV n-transfer, stable d + 57Fe → 2·p + 58Fe + 531 keV n-transfer, stable 7Li + 61Ni → 3He + 4He + 62Ni + 76 keV n-transfer, stable, α 7Li + 61Ni → 7Be + 62Ni + 1663 keV n-transfer, →ε 7Li + 57Fe → 7Be + 58Fe + 1111 keV n-transfer, →ε 7Li + 54Fe → 7Be + 55Fe + 365 keV n-transfer, →ε 7Li + 58Ni → 7Be + 59Ni + 66 keV n-transfer, →β+, →ε
I'm guessing that all of these reactions are only energetic if the pion exchange occurs simultaneously with the decay to lighter daughters, as is being modeled here. The last reaction there would result in annihilation gammas if it occurred at any significant rate. Note the two 62Ni-producing reactions, which are relevant to the Lugano test. Eric