Photoionization of Be-like N3+ and Ne6+ ions: features of Be isoelectronic sequences of Z ⩽ 10

Using a noniterative eigenchannel R-matrix method, we have studied the photoionization for ground 1S and excited 3,1P initial states of the Be-like N3+ and Ne6+ ions, up to the energy range of the final photo-ionic 3d state. The autoionizing resonance structures arising from the ground and excited states are identified and characterized. Our calculated photoionization cross sections with excellent agreement between length and velocity gauges are compared with the available experimental and previous theoretical results, and good agreement is shown. For the isoelectronic sequences of Z ⩽ 10, the Z-dependent spectral structures and developments of the cross sections are discussed based on the present results of N3+ and Ne6+ ions and the previous results of other ions obtained by the same noniterative eigenchannel R-matrix method. The intermixing among the resonances converging to the final photo-ionic 2p and the various 3l states is increased as Z, resulting in a much more complex pattern of resonances for the photoionization.