Level structure of 17O from neutron total cross sections

The neutron total cross section of oxygen is measured in the energy regions from 0.6 to 0.9, 1.12 to 1.16, and 1.39 to 4.33 MeV. More than half of this region is surveyed with energy resolution and energy steps of about 2.5 keV. On the basis of these data and supplementary published data on the (n,n) angular distributions and the ¹³C(α,n) reaction, the ¹⁷O level energies in MeV and, in parenthesis, $J^{\pi }$ values and center-of-mass total widths, ${\Gamma }_T={\Gamma }_n+{\Gamma }_{\alpha }$ in keV, are: 5.696 (7/2⁻, 3.4); 5.731 (not 1/2⁺, 1.0); 5.867 (3/2⁺, 6.6); 5.937 (1/2⁻, 32); 6.354 (1/2⁺, 124); 6.860 (not 1/2⁺, 1.0); 6.970 (not 1/2⁺, 1.0); 7.163 (5/2⁻, 1.4); 7.20 (3/2⁺, 280); 7.377 (5/2⁺, 0.5); 7.380 (7/2⁻, 1.2); 7.56 (3/2⁻, 500); 7.685 (7/2⁻, 18); 7.955 (1/2⁺, 90); 7.99 (1/2⁻, 260); 8.058 (3/2⁺, 86); 8.18 (1/2⁻, 69); and 8.20 (3/2⁻, 52). Resonances are not observed for known ¹⁷O levels at 5.215 and 7.573 MeV; these levels have Γ_T0.1 keV. The previously reported narrow 3/2⁺ level at 7.694 MeV does not exist. Many of the results are based on a multilevel R-matrix analysis; this is also extended to the published ¹⁶O(n,n) and ¹³C(α,n) cross sections for energies corresponding to ¹⁷O excitations up to 9.5 MeV. This extension shows that there are two levels rather than only one near 8.47 MeV and that the 9.42-MeV level has $J^{\pi }={\frac{3}{2}}^{-}$. Other assignments are confirmed. The most accurate excitation energies below 9.5 MeV are reviewed from the literature and the ¹⁷O-¹⁷F mirror structure is reviewed.