Study of the Low-Lying States ofCl38via the ReactionCl37(

Abstract

Levels of Cl below an excitation energy of 2.75 MeV have been studied with the reaction C13 (d,py) C13 at a deuteron bombarding energy of 3.1 MeV. y-ray branching ratios and Doppler-shift information were obtained from proton-y coincidence measurements using BaCl& targets enriched in Cl~. Excitation energies were determined from singles measurements, as well as from the coincidence studies for the 10 levels previously reported in this energy range. The J~=1+ level at 1942 keV, which is strongly excited in the p decay of S38 and which was not observed in Cl (d,p)C1 studies with a magnetic spectrograph, is also weakly populated. Excitation energies (in keV) and mean lives (in psec) for the lowest 10 levels are . The multipole strengths of the transitions linking these states with the 2 ground state and 5 first excited state lead in combination with the l" transfer values from previous (d,p) work to the following spin-parity assignments: J~(755) =3;

Shell-model relationships between negative-parity states of even-massA=30?40 nuclei

“…The second and third 3-states with T=0 were, however, predicted more than 1MeV above the observed levels at 5 [25] also included like Ern6 [,163 the 5.90MeV levels as a lowest 4-member and calculated a large spectroscopic factor Sp (l--3) for this level, which is however not excited in the 35C1 (z,d)36Ar reaction [27]. The second and third 3-states with T=0 were, however, predicted more than 1MeV above the observed levels at 5 [25] also included like Ern6 [,163 the 5.90MeV levels as a lowest 4-member and calculated a large spectroscopic factor Sp (l--3) for this level, which is however not excited in the 35C1 (z,d)36Ar reaction [27].…”

“…2.1. The 0 and 1-spin assignments to the T=I, dtp multiplet states at 2.63 and 2.10MeV, respectively, in 4~ are according to the Pandya transformation by Engelbertink and Olness [5]. Uncertain values due to ambiguous spin assignments are cited between ( ) brackets and centroids of fragmented states between ( ) brackets.…”

“…(12) where j=lfT/2 for the df multiplet and j=2p3/2 for the dp multiplet. The "average" position of the higher dp quadruplet is however not arbitrarily [5] assumed, but the energy separation between the two multiplets can be determined [30] by subtraction as (12) can be extended to include isospin in the formalism, in order to obtain a comprehensive interpretation of the low-lying negative-parity states of 3SK (T=0), 3BAr The "average" position of the higher dp quadruplet is however not arbitrarily [5] assumed, but the energy separation between the two multiplets can be determined [30] by subtraction as (12) can be extended to include isospin in the formalism, in order to obtain a comprehensive interpretation of the low-lying negative-parity states of 3SK (T=0), 3BAr…”

“…Assuming these to be due to pure ld~/2 configurations coupled to a closed 32S core in terms of the simplest shell model, the addition of a lf7/2 nucleon to such a state results in an even-nucleus configuration with possible J~ values 2-, 3-, 4-and 5-. With more recent experimental data on *OK becoming available, also a higher, related negative-parity multiplet with dominant ltd3/2 v P3/2 configuration and spins J=0, 1, 2 and 3 was identified in 3sc1 by Engelbertink and Olness [5]. Goldstein and Talmi [4] independently established a similar relationship between the d3/2fT/2 (= d3/12 f7/2) configuration of 4~ and the d3/2fT/2 configuration of 38C1, however, employing coefficients of fractional parentage (cfp).…”

“…Here the constant terms have been computed from: binding energy differences between a~ and the 2Ssi closed core as well as between 32p/c1 and the a2S closed core; the Coulomb energy difference for 32C1/8; and the 2S1/2, lf7/2 and 2p3/2 single-particle (5) or -hole (e) energies taken from the observed spectra of 298i and 33S (neutron), 29p and 33C1 (proton), as well as the 32S doubly-closed core. The level systematics of the recent nuclear data compilation of Endt and van der Leun [7] and the binding energy values of Wapstra and Bos [8-1 have been used.…”