Energy Levels ofLu174

Abstract

Thirty-two levels in ${\mathrm{Lu}}^{174}$ have been observed up to an excitation energy of 1628 keV utilizing 12-MeV deuterons and the reaction ${\mathrm{Lu}}^{175}(d, t){\mathrm{Lu}}^{174}$. The ground-state $Q$ value was determined to be -1400±15 keV. The spectrum has been interpreted in terms of the coupling of the [404↓] Nilsson proton orbital with the neutron orbitals prominent in the ($d, t$) spectrum of ${\mathrm{Yb}}^{173}$. This interpretation has resulted in the determination of relative energies due to the residual neutron-proton interaction for seven different configurations. The observed singlet-triplet splitting energies for the [512↑], [521↓], and [521↑] neutron orbitals coupled to the [404↓] proton orbital were measured to be -110, +80, and -90 keV, respectively. Theoretical calculations of these energies made for a zero-range spin-dependent central potential gave values of -106, +71, and -77 keV, respectively. The remarkable agreement indicates that the spin-spin interaction can account for most, if not all, of the singlet-triplet splitting energy.