Interchannel coupling in ionic photoionization far above threshold: The neon isoelectronic sequence

A study of the evolution of interchannel coupling in the photoionization of the Ne isoelectronic sequence from neutral Ne to Fe16+ has been performed. As in neutral Ne, the 2s cross section dominates the 2p at a high enough energy over the entire sequence and affects the 2p photoionization cross section via interchannel coupling. The importance of this coupling decreases gradually with increasing nuclear charge along the sequence. This has implications for databases of photoionization rates of astrophysical importance.