Magnetic-Dipole Transitions in the (πd32)(νf72) Quartet

The mean lives of the second and third excited states in ${}_{}{}^{40}{}_{}{}^{}\mathrm{K}$ are (0.65 ± 0.15) × ${10}^{-12\mathrm{}}$ and (1.6 ± 0.3) × ${10}^{-12\mathrm{}}$ sec, respectively. The relative speeds of the three $M1\mathrm{}$ transitions between the four lowest states are incompatible with these states being pure ${\left(\pi d_{\frac{3}{2}}\right)}^{-1\mathrm{}}\times \left(\nu f_{\frac{7}{2}}\right)$-even if effective moments are used; neither small components of the most likely shell-model impurities nor any possible $E2\mathrm{}$ admixture improves the fit. A similar situation appears to hold in ${}_{}{}^{38}{}_{}{}^{}\mathrm{Cl}$.