Effects of the exchange Slater integrals on the shapes of transition arrays

Many atomic transition arrays exhibit remarkable shapes. First, some arrays are strongly asymmetrical. Secondly, when spin-orbit interactions split an array into sub-arrays, the breakdown of j-j coupling may yield large strength transfers between them. Thirdly, in the case of configuration mixing, strength transfers are also observed between whole arrays, and they are sometimes nearly complete. All these changes of the shapes of transition arrays are due to the effects of Slater exchange integrals on the statistical distribution of the line strengths. It is shown how they can be introduced for improving the statistical line-by-line simulation of resolved transition arrays (the RTA model). (C) 2000 Elsevier Science Ltd. All rights reserved.