Isotopic Spin and Coulomb Forces

The importance of the coulomb forces in mixing states with a different isotopic spin T is investigated assuming charge independence of the specific nuclear forces. It is found that for two and four nucleons outside a closed shell in the state T =0 this mixing is very small (less than 0.25%, taking into account interconfigurational mixing). It can therefore be concluded that the coulomb forces have very little importance in destroying the validity of the isotopic spin selection rules for β and γ transitions and for collisions, which result from the assumption of the charge independence of nuclear forces.