Shell-Model Analysis of the Level Structure ofAr41

Levels of ${\mathrm{Ar}}^{41}$ experimentally observed up to excitation energy of 4.5 MeV are considered. Using experimental data from neighboring nuclei the positions of 40 odd-parity states are calculated in the framework of the shell model. Good agreement is obtained for the low-lying levels. Approximate treatment of the $d_{\frac{3}{2}}^{}{}_{}{}^{2}f_{\frac{7}{2}}^{}{}_{}{}^2{p}_{\frac{3}{2}}$ and $d_{\frac{3}{2}}^{}{}_{}{}^{2}f_{\frac{7}{2}}^{}{}_{}{}^2{p}_{\frac{1}{2}}$ configurations in addition to the $d_{\frac{3}{2}}^{}{}_{}{}^{2}f_{\frac{7}{2}}^{}{}_{}{}^3$ ground configuration gives a semi-quantitative account of all odd parity 3/2 and 1/2 levels up to 4.5 MeV. Many odd-parity levels with $J>\mathrm{}\frac{3}{2}$ which were not yet found experimentally are predicted to be in this region.