PHOTO-IONIZATION CROSS-SECTION OF THE OPEN 3P SUBSHELL IN ATOMIC CHLORINE

The 3p photoionization of neutral chlorine is calculated below 5 Ryd. We show that for such an open shell system, intra- and interchannel effects are all important. They are treated with the R matrix theory in two kinds of calculations, one of them involving a 3d pseudoorbital. Beyond the Cl** plus **1 S**e threshold, our results are compared with those given by a central potential model or those obtained by other authors with the R. P. A. E. or many body methods. The autoionization lines are obtained for the first time. We then compare some of the calculated quantities with those obtained for two other members of the same isoelectronic series :Ar** plus and K**2 ** plus .