Charge-dependent three-body potential with one photon and one pion exchanged was derived. Only the dominant lowest-order processes which arise from the Born terms of the internal processes are investigated. The contribution of this charge-dependent three-body potential to the binding energy difference of ${}_{}{}^3{}_{}{}^{}\mathrm{He}$-${}_{}{}^3{}_{}{}^{}\mathrm{H}$ is then evaluated using a realistic variational wave function and found to be small but not negligible.

NUCLEAR STRUCTURE ${}_{}{}^3{}_{}{}^{}\mathrm{He}$, ${}_{}{}^3{}_{}{}^{}\mathrm{H}$, Charge-dependent three-body force, Coulomb energy.

• Received 31 May 1978

DOI:https://doi.org/10.1103/PhysRevC.19.1114