The Sussex harmonic oscillator matrix elements are employed to estimate the effect of cross terms between the nuclear interaction and the Coulomb potential. The 2p, 3p1h, and 4p2h corrections are calculated with second order perturbation theory. The resulting matrix elements of the charge dependent interaction yield excellent agreement with observed isospin mixing in ${}_{}{}^8{}_{}{}^{}\mathrm{Be}$. Comparison is made to $G$-matrix calculations.

NUCLEAR STRUCTURE Sussex matrix elements. Coulomb shifts. Isospin mixing ${}_{}{}^8{}_{}{}^{}\mathrm{Be}$.

• Received 14 October 1974

DOI:https://doi.org/10.1103/PhysRevC.11.1422