W. Parker Alford

The structure of 36Ar and 38Ar via the (3He, d) reaction on 35Cl and 37Cl

Abstract The level structures of 36Ar and 38Ar have been investigated with the 35,37Cl(3He, d) 36,38Ar reactions at a bombarding energy of 12 MeV. Deuteron angular distributions were measured for 31 levels in 36Ar up to 8.5 MeV excitation and 29 levels in 38Ar up to 6.9 MeV excitation. The lp values and transition strengths were determined from a distorted wave Born analysis of the angular distributions. The results for the positive parity states of 36Ar and 38Ar are in reasonable agreement with a shell-model calculation which considers only Id 3 2 and 2 s 1 2 nucleons outside a closed 28Si core. The major components of the ( f 7 2 d 3 2 5 ) T = 1 configuration in 38Ar for Jπ = (3, 4, 5)− and of the ( f 7 2 d 3 2 3 ) T = 0 configuration in 36Ar for Jπ = (3, 5)− were identified. For the f 7 2 transitions in 38Ar, and to a lesser extent in 36Ar, the observed severe fragmentation of strength shows that a model involving core polarization rather than a simple weak coupling model is applicable in describing the structure of these nuclei. All the p 3 2 . transition strength to T P 3 2 −f 7 2 single-particle energy splitting is significantly smaller in 36Ar than in 38Ar. The angular distributions of all known 3− states are consistent with mixed l = 1+3 transitions, showing that configuration admixtures between the ( p 3 2 d n 3 2 ) and ( f 7 2 d n 3 2 ) configurations are important.