Levels of 39Cl studied by the 40Ar(d, 3He) 39Cl reaction at 52 MeV

Abstract

Levels of 39Cl were populated by the 40Ar(d, 3He) 39Cl reaction at an incident energy of 52 MeV. A range of 7 MeV of final excitation was covered; 16 levels were observed, 14 of which were not known before. Spin and parity assignments to the majority of these levels were accomplished by a DWBA analysis of the angular distributions and by utilizing the j-dependence of the l = 2 angular distributions observed in the 32S(d, 3He) 31P reaction. The 1 d 3 2 and 2 s 1 2 hole strengths are essentially concentrated in one single state each. These are considered as dominant 2p-3h states with respect to 40Ca. The small energy gap of only 0.7 MeV between the 1 d 3 2 and 2 s 1 2 centers of gravity is understood from the properties of the s-f and d-f effective interactions. The observed l = 3 strength yields evidence for proton core excitations which are of comparable size to those in the calcium isotopes. Excitations of 2s protons into the f-shell contribute significantly. The d 5 2 hole strength is strongly fractionated with a center of gravity as low as 4.5 MeV of final excitation.