Electron-impact excitation of B+ using theR-matrix with pseudo-states method

We have carried out several R-matrix with pseudo-states (RMPS) calculations for the electron-impact excitation of B+. Maxwell-averaged effective collision strengths have been determined for excitations between the lowest 20 terms, including all those arising from the 2s3l and 2s4l configurations. A comparison of results from 114 term and 134 term close-coupling (CC) RMPS calculations demonstrates the convergence in the pseudo-state expansion representing the continuum and high bound-states. Comparison of the 114CC RMPS results with those from a 20CC R-matrix calculation, using the same 114 term configuration interaction target, shows a reduction in the effective collision strengths by up to a factor of two at higher temperatures for transitions to n = 4. The modelling of spectral emission from boron, and from n = 4 terms in B+ in particular, is important for studying impurity influx in both current (TEXTOR) and future (ITER) magnetic fusion reactors. 1