Proton single-particle states have been studied in the isotopes ${}_{}{}^{249}{}_{}{}^{}\mathrm{Bk}$, ${}_{}{}^{241}{}_{}{}^{}\mathrm{Am}$, and ${}_{}{}^{231}{}_{}{}^{}\mathrm{Pa}$. The reaction ($\alpha , t$) was utilized in the three studies. Additionally, the reaction (${}_{}{}^3{}_{}{}^{}\mathrm{He}$, $d$) was used in the study of levels in ${}_{}{}^{249}{}_{}{}^{}\mathrm{Bk}$. Many new levels were observed and some could be interpreted in terms of single-particle orbitals. Also several assignments previously made on the basis of radioactive decay studies were confirmed by the orbital signatures seen in the proton transfer spectra. Single-particle energies are extracted from the experimental data. Deformations of the nuclear central potential are deduced for ${}_{}{}^{249}{}_{}{}^{}\mathrm{Bk}$ and ${}_{}{}^{241}{}_{}{}^{}\mathrm{Am}$. By use of the parameters of the central field for ${}_{}{}^{249}{}_{}{}^{}\mathrm{Bk}$, the $f_{\frac{7}{2}}-f_{\frac{5}{2}}$ splitting is deduced for mass 250 at zero deformation and estimated for mass 300.

NUCLEAR REACTIONS ${}_{}{}^{248}{}_{}{}^{}\mathrm{Cm}({}_{}{}^3{}_{}{}^{}\mathrm{He}, d)$, ${}_{}{}^{248}{}_{}{}^{}\mathrm{Cm}$, ${}_{}{}^{240}{}_{}{}^{}\mathrm{Pu}$, ${}_{}{}^{230}{}_{}{}^{}\mathrm{Th}(\alpha , t)$ $E=29\mathrm{}$ MeV; measured $E$ (excitation), $\sigma$; deduced orbitals, s.p. energies, deformations in ${}_{}{}^{249}{}_{}{}^{}\mathrm{Bk}$, ${}_{}{}^{241}{}_{}{}^{}\mathrm{Am}$, ${}_{}{}^{231}{}_{}{}^{}\mathrm{Pa}$.

• Received 26 August 1974

DOI:https://doi.org/10.1103/PhysRevC.11.561