ELECTRON-IMPACT EXCITATION OF AL-II

Using configuration interaction wavefunctions collision strengths OMEG A are calculated for transitions among the lowest 12 excited states of the (1s(2)2S(2)2p6) 3s2, 3p2, 3s3p, 3s3d, 3s4s and 3s4p configuration of Al II. The standard and no-exchange R-matrix programs are employed for computing the contributions of OMEGA for L less-than-or-equal-to 12 and L > 12 respectively. Pseudoresonances have been removed and the results are listed at 10 energies in the range 1.5 to 10 Ryd. A compa rison of present results shows the earlier available collision strengt hs to be in error by over an order of 3 for some of the transitions. T his error arose mainly in the computation of the contribution of OMEGA for L>6 in the earlier results. However, the differences are discusse d and the accuracy of our present collision strengths is assessed.