Forbidden transitions in Li-like ions: Compact effective collision strengths for 2s-ns, nd where n=3, 4, 5

Using an extension of the method for compacting atomic data set out by Burgess & Tully (1992), we make concise fits to a selection of the set of collision strengths Omega given by Zhang et al. (1990) far Li-like ions from O+5 to U+89. We carry out thermal averaging and fit the resulting effective collision strengths Upsilon. A compact 5 x 5 or 4 x 4 table of cardinal values for each transition allows one to reproduce the T and Z dependent Upsilon to better than 1 per cent. The present study is for the forbidden transitions 2s --> 3s, 4s, 5s and 2s --> 3d, 4d, 5d.