Neutron rich 73Ga and 79As isotopes via the (α,p) reaction

The (α,p) reaction at 26 MeV has been used to study 73Ga and 79As with 12 keV resolution (FWHM). The reaction behaves like a simple proton stripping ('spectator' zero coupled neutron pair) and the characteristic shapes of the angular distributions permit to assign new spins and parities. In 73Ga: 198 keV (5/2-), 1116 keV (1/2-), 1494 keV (9/2+). In 79As: g.s (3/2-), 233 keV (5/2-), 499 keV (1/2-), 777 keV (9/2+), 1806 keV (9/2+), 1891 keV (1/2-), 1964 keV (9/2+). The observed splitting of the Jsup(π)=3/2- strength in 73Ga, important as compared to the one observed in 71Ga, is attributed to a change of structure between N=40 and 42