Partial decay widths of the lowest $T=2\mathrm{}$ state of ${}_{}{}^8{}_{}{}^{}\mathrm{Be}$ are calculated using ${\mathrm{}\left(1p\right)\mathrm{}}^4$ shell-model wave functions. Agreement with experiment is improved if there is, in addition to the Coulomb force, a charge-dependent component of the nuclear force with magnitude close to that suggested by nucleon-nucleon scattering data. The calculations are able to account for the empirical values of the isobaric multiplet mass equation $b$ and $c$ coefficients for $A=8\mathrm{}$, $T=2\mathrm{}$, and provide an explanation of why the quadratic form of the isobaric multiplet mass equation is inadequate for this multiplet.

NUCLEAR STRUCTURE Isospin mixing in mass 8, charge-dependent forces, IMME coefficients.

• Received 13 September 1982

DOI:https://doi.org/10.1103/PhysRevC.27.846