Shell Model States in ¹³⁸La

Abstract

<p>A ·cornbinationof particle andy-r';'ij' spectroscopy. has: . ,: '., \". '. " ~:'" been utilized' to elucidate the nuclear structure ,~'f 138La . The'~in</p> <p>The complementary information from the proton transfer and neutron pick-up reactions, together with their spin assignments, is used to analyze the wave functions for the twelve lowest levels. These appear to be simple shell model states arising from the coupling of a neutron hole in the 2d₃⁄₂ or 3s½ orbit to the j = 7/2 or 5/2 proton configurations observed at low energy in ¹³⁹La.</p> <p>Two groups of negative parity states, predicted by the simple shell model, have also been identified. Unfortunately only tentative spin assignments, based on the 2J+1 rule for spectroscopic strengths have been possible for most of these because the (p,n) reaction does not populate the many high spin states involved.</p> <p>A lowest seniority shell model calculation, employing the surface delta interaction, was carried out for the low-lying levels. Spectroscopic factors are calculated for both the proton transfer and neutron pick-up reactions. A comparison with the experimental findings shows disappointing agreement.</p>