The K \alpha resonance complexes in oxygen ions O I - O VI are theoretically computed and resonance oscillator strengths and wavelengths are presented .
The highly resolved photoionization cross sections , with relativistic fine structure , are computed in the coupled channel approximation using the Breit-Pauli R-matrix method .
A number of strong K \alpha resonances are found to be appreciable , with resonance oscillator strengths f _ { r } > 0.1 .
The K \alpha resonance wavelengths of O I-O-VI lie in a relatively narrow wavelength range 22 - 23.5 \AA , and the X-ray opacity in this region should therefore be significantly affected by K \rightarrow L transitions in oxygen .
The results should be useful in the interpretation of soft X-ray spectra observed from Chandra and XMM-Newton .