Nuclear Levels inPr142

A combination of ($d,p$)-reaction spectroscopy and high- and low-energy $\gamma$ rays following thermal-neutron capture in ${}_{}{}^{141}{}_{}{}^{}\mathrm{Pr}$ has been used to study the levels in ${}_{}{}^{142}{}_{}{}^{}\mathrm{Pr}$. The ($d,p$) reaction populates 65 states below 2 MeV, whereas 37 states below 2 MeV are populated by high-energy $\gamma$ transitions from thermal-neutron capture. The ground-state $Q$ value determined in the ($d,p$) reaction is 3622±3 keV, in agreement with the neutron binding energy of 5843.4±1.5 keV. Differential cross sections were measured at nine angles for the ($d,p$) reaction and interpreted in terms of the distorted-wave Born-approximation reaction theory. Utilizing, in addition, some of the low-energy $\gamma$ rays observed with a bent-crystal spectrograph and with a Ge(Li) spectrometer, it has been possible to make the following assignments (energy in keV, spin and parity in parentheses): ground state, (2—); 3.683, (5—); 17.740, (3—); 63.746, (6—); 72.294, (4—); 84.998, (1—); 128.251, (5—); 144.587, (4—); 176.863, (3—); and 200.525, (2—). These states are interpreted in terms of configuration mixing between the two configurations $\pi {d_{\frac{5}{2}}}^1\nu {f_{\frac{7}{2}}}^1$ and $\pi {g_{\frac{7}{2}}}^{-1\mathrm{}}\nu {f_{\frac{7}{2}}}^1$. Not only the energies of the levels but also the transition probability ratios are consistent with this interpretation. The calculated half-life of the 3.683 keV, 5— isomeric state is in reasonable agreement with the experimental value. Tentative spin and parity assignments have been made to levels above 250 keV.