Photoionization of the Be isoelectronic sequence: total cross sections

The photoionization of the four-electron beryllium-like isoelectronic series from the neutral to Fe(+22) has been studied for ground (1)S and metastable (3)P initial states. The wavefunctions of the final-state (target) ions were built using the CIV3 code. Both nonrelativistic LS-coupling R-matrix and relativistic Breit-Pauli (BP) R-matrix methods were used to calculate the cross sections in the photon-energy range between the first ionization threshold and the 1s(2)4f(7/2) threshold for each ion. Our total cross sections compare well with experiment which is available for Be, B(+), C(+2), N(+3) and O(+4). The agreement between the present work and previous calculations is discussed in detail. The importance of relativistic effects is seen by the comparison between the LS and the BP results.