Coulomb Energies of Light Nuclei

The Coulomb energy differences of light nuclei, determined mostly from β decay, are fitted to a formula ΔEc=a(ZA1/3)+b, where b is an exchange term. With modern data, the nuclear series $A=4n, 4n+1, 4n+2, 4n+3$ all yield surprisingly consistent values: $a=1.46$ Mev, b=-1.11 Mev. The data very clearly exhibit the presence of the exchange term; the value of a corresponds to a square well radius, R=1.18A1/3×10^-13 cm. The ΔEc formula is combined with β-decay energies to determine the spacing Δ_TT^' of the lowest-lying states of isotopic spins T, T^' for a given A. The observed behavior of the Δ provides qualitative evidence for dominant supermultiplet structure in light nuclei.