Low-lying E1 strength in ²⁰O

Intermediate energy Coulomb excitation at 100 MeV/nucleon was used to probe the low-lying level structure of both ¹⁸O and ²⁰O in the region between 1 and 8 MeV. Discrete 1^- states with energies of 5.35(10) and 6.85(5) MeV were observed in ²⁰O. The strong direct excitation and subsequent γ-ray decay of these states, along with B(Eλ) predictions for ^18,20O levels in this energy region, established their dipole character. The extracted B(E1)↑ values of 0.062(16)e² fm² and 0.035(9)e² fm² for the 5.35- and 6.85-MeV states, respectively, are significantly larger than shell model calculations, though modification of the single-particle energies, in particular, the p-sd shell gap, improves the agreement, The summed B(E1)↑ value for these levels (in Weisskopf units) is consistent with that for other nuclei that have been discussed recently in the literature as potential Pygmy dipole resonance hosts.