(p,α) reaction onNb93andY89

The ($p,\alpha$) reaction has been studied at 15.2 MeV on ${}_{}{}^{93}{}_{}{}^{}\mathrm{Nb}$ and ${}_{}{}^{89}{}_{}{}^{}\mathrm{Y}$ and analyzed using distorted-wave Born-approximation and cluster form factors. The reaction is a direct triton pickup and compound nucleus effects are negligible. In the first case the transferred neutrons are the two extra core neutrons and the reaction behaves like a proton pickup. Positive parity states of ${}_{}{}^{90}{}_{}{}^{}\mathrm{Zr}$ are populated by the transfer of $g_{\frac{9}{2}}$ protons with strengths in good agreement with a simple model; new levels are excited corresponding to $p_{\frac{3}{2}}$ and $f_{\frac{5}{2}}$ proton holes. In the second case the neutrons are removed from the filled $N=50\mathrm{}$ shell; states corresponding to proton and neutron configurations in ${}_{}{}^{86}{}_{}{}^{}\mathrm{Sr}$ are excited with comparable strengths and it is difficult to get unambiguous spectroscopic information.