The nuclides ' K, Ca, and ' Sc have been produced by fragmentation of a uranium target with a 600 MeV proton beam. The subsequent P decays to the daughter nuclei '2Ca, ' Sc, and ' Ti have been studied by neutron and y spectroscopy on sources obtained from on-line mass separation. P decay energies have been determined by P-y coincidence spectroscopy. In addition to the short halflife of K (Tl&2 --110+30 ms), we attributed two different half-lives (Tlq2 --4.6+0.3 s and Tl~2 --8.2+0.2 s) to ' Ca and ' Sc, respectively. A decay scheme has been established for ' K involving five P branches to delayed neutron emitting states between 6.6 and 10.3 MeV and one P branch to a bound level at E"=2.56 MeV. The ' Ca decay scheme accounts for 13 branches to four levels at 1.64, 2.75, 3.46, and 4.27 MeV for which the deduced logft values restrict the angular momentum and parity to J =1+. For the "Sc ground state, strong P transitions to the 2+ (1.05 MeV) and the (4+) (2.32 MeV) levels in '2Ti strongly favor a J =3+ attribution. The measured gp values for the Ca (5.7+0.2 MeV) and Sc (8.02+0.25 MeV) decay are noticeably lower than expected from mass systematics. The energy level diagrams of ' Ca, Sc, and ' Ti nuclei have been calculated in the framework of the shell model with a realistic interaction. Good agreement between theory and experiment is achieved as well for excitation energies as for mass excesses, assuring then the applicability of the theory to this region of nuclei far from stability.

The 34,35 Al ␤ decays have been studied at the CERN online mass separator ISOLDE by ␤-␥, ␤-␥-␥, and ␤-n-␥ measurements in order to corroborate the low-level description of 34 Si and to obtain the first information on the level structure of the Nϭ21 isotope 35 Si. Earlier observed ␥ lines in 34 Al decay were confirmed and new ␥ transitions following both ␤ decay and ␤-delayed neutron emission have been established. The first level scheme of 35 Si includes three excited states at 910, 974, and 2168 keV. Indication is found for J ϭ(3/2) Ϫ and (3/2) ϩ for the first two excited states, respectively. Beta-decay half-life of T 1/2 ϭ38.6(4) ms and ␤-delayed neutron branching value P n ϭ41(13)% were measured unambiguously. The significance of the single-particle energy determination at Nϭ21, Zϭ14 for assessing the effective interaction in sd-f p shellmodel calculations is discussed and illustrated by predictions for different neutron-rich isotopes.