The neutron energy from deuterium fusion is ∼ 2.45 MeV (hyper physics gsu.edu). It represents approximately a neutron velocity of 7.2 % of c. Fusion of neutrons with protons give (m n + m p -m D )c 2 > 0 or in terms of a.u. viz. , (m n + m p -m d ) × 932 = 2.79MeV. This represents an overshoot of energy where certain losses like uncertainty and e.g. neutron-proton overlap 1 -cos rmnc 2 vℏ viz. (45), must be incorporated. The concept is that if a neutron diameter, at 2.45 MeV spans approximately 2 peaks and a proton diameter does so as well, then a fusion reaction occurs.