Low-Energy Nuclear Level Scheme ofRh104

Investigations of the low-energy level properties (level energies, spins, and parities) of ${\mathrm{Rh}}^{104}$ have been undertaken from studies of the coincidence relationships existing between the low-energy capture gamma rays produced by thermal neutron capture in ${\mathrm{Rh}}^{103}$ using NaI(Tl) scintillation crystals as detectors. It is known from the decay scheme of the 4.4-min ${\mathrm{Rh}}^{104m}$ isomer that ${\mathrm{Rh}}^{104}$ has energy levels at 52, 96, and 129 keV with spins and parities of 2-, 2+, and 5+, respectively. The data obtained in these investigations have been combined with the isomeric level data in order to determine the properties of several additional levels. Additional levels in ${\mathrm{Rh}}^{104}$ have been determined at the following energies, with the level spin and parity in parenthesis after the energy; 184 keV (1±), 192 keV (3+), 269 keV (3±), 450 keV, and either 229 keV (3+) or 325 keV (4+). These spin and parity assignments were made on the basis of a $K$ internal conversion coefficient analysis of the coincidence data together with consideration of the relative cascade intensities. On the basis of the possible odd-proton and odd-neutron configurations open to the 184- and 269-keV levels, and considering the transition intensities to the lower levels, it was determined that the negative-parity assignment is most probable for both of these levels, with the levels having configuration assignments of $\left(p_{\frac{3}{2}}\right)\left(d_{\frac{5}{2}}\right)$. The 192-keV level together with the 229- or 325-keV level most probably have either ${\left[{\left(g_{\frac{9}{2}}\right)}^5\right]}_{\frac{7}{2}}{\left(d_{\frac{5}{2}}\right)}^n$ or ${\left(g_{\frac{9}{2}}\right)}^5{\left(d_{\frac{5}{2}}\right)}^n$ configurations. In fact, if it is the 229-keV level which does exist, as the available evidence might seem to indicate, then, since they both have spins and parities of 3+, the 192-keV level would have one of these configurations while the 229-keV level would have the other.