The $^{34,35}Al$ beta decay to $^{34,35}Si$

The /sup 34,35/Al beta decay was studied at the CERN on-line mass- separator ISOLDE by beta - gamma , beta - gamma - gamma and beta -n measurements. In the /sup 34/Al decay, the new data confirm the previous results and complement the level scheme in /sup 34/Si and /sup 33/Si. An intruder (2p-2h) O/sub 2//sup +/ state is proposed at 2.1 MeV in /sup 34/Si in, agreement with different shell-model predictions but its decay is still unobserved. A /sup 35/Al beta - decay scheme to /sup 35/Si bound and unbound states is established. The /sup 35/Al half life (41.6(22) ms) was measured with a good precision. The first /sup 35/Si level scheme including three levels at 911, 974 and 2169 keV with respectively J/sup pi /=(3/2)/sup -/, (3/2)/sup +/ and (5/2)/sup +/ was obtained. The spin and parity values are consistent with a (5/2)/sup +/ assignment for the /sup 35 /Al ground state. The value P/sub n/=0.41(13) was also deduced. New information on the proton-neutron interaction in the (sd-fp) space is obtained. (11 refs).