Shell-model predictions for sup 41,42 Cl(. beta. sup minus ) sup 41,42 Ar and the A =41--43 Ar isotopes

Shell-model calculations in the model space of the (0{ital d},1{ital s}) and (0{ital f},1{ital p}) major shells are made for the 1/2{sup +} and 3/2{sup +} states of {sup 41}Cl, the odd-parity states of {sup 41}Ar, and the even-parity states of {sup 42}Ar. Calculations for {sup 42}Cl, the even-parity states of {sup 41}Ar, and the odd-parity states of {sup 43}Ar were performed with various degrees of truncation. The results for the {sup 41}Cl ground state indicate {ital J}{sup {pi}}=3/2{sup +} with a binding energy of {minus}345 183 keV in excellent agreement with the experimental value of {minus}345 020{plus minus}150 keV. The predicted binding energies of {sup 41{minus}43}Ar are also in good agreement with experiment. The wave functions for the {ital A}=41 and 42 nuclei are used to calculate first-forbidden {beta}{sup {minus}}-decay rates. The 1/2{sup +} and 3/2{sup +} states of {sup 41}Ar are considered in a truncated model space and the results are used to estimate the allowed {beta}{sup {minus}}-decays rates of {sup 41}Cl. Spectroscopic factors and electromagnetic transition rates are calculated for {sup 41}Ar and compared to experiment. {sup 43}Ar is predicted to have a 5/2{sup {minus}} ground state.