Properties of the Argon Isotopes

The properties of the low-lying states of the argon isotopes ${}_{18}{}^{39}{}_{}{}^{}\mathrm{Ar}_{21}^{}{}_{}{}^{}$, ${}_{18}{}^{40}{}_{}{}^{}\mathrm{Ar}_{22}^{}{}_{}{}^{}$, ${}_{18}{}^{41}{}_{}{}^{}\mathrm{Ar}_{23}^{}{}_{}{}^{}$, and ${}_{18}{}^{42}{}_{}{}^{}\mathrm{Ar}_{24}^{}{}_{}{}^{}$ are predicted by use of both the ${\left(\pi d_{\frac{3}{2}}\right)}^{-2\mathrm{}}{\left(\nu f_{\frac{7}{2}}\right)}^n$ model and the extended ${\left(\pi d_{\frac{3}{2}}\right)}^{-2\mathrm{}}{(\nu f_{\frac{7}{2}}, \nu p_{\frac{3}{2}})}^n$ description. The $n-n$, $p-p$, and $n-p$ interactions are taken from data on neighboring nuclei. With the extended model, reasonable agreement with experiment is obtained for the spectra. $E2\mathrm{}$ and $M1\mathrm{}$ transitions rates are examined. All $M1\mathrm{}$ transitions are predicted to be substantially inhibited, as is observed experimentally. Several experiments are suggested.