Excited States ofAr40Observed in the ReactionAr40(γ, n0)Ar39

We identify 27 excited states of ${}_{}{}^{40}{}_{}{}^{}\mathrm{Ar}$ in the energy range 10.4-12.5 MeV from the photoneutron spectrum of ${}_{}{}^{40}{}_{}{}^{}\mathrm{Ar}$ irradiated with 12.5-MeV bremsstrahlung. These levels are probably associated with the promotion of one of the $1f_{\frac{7}{2}}$ valence neutrons into the continuum. The distribution of radiation strength in this region suggests the presence of a single-particle resonance in ${}_{}{}^{40}{}_{}{}^{}\mathrm{Ar}$ at ∼ 10 MeV.