APPLICATION OF DIRECT-METHODS TO POWDER DATA - A WEIGHTING SCHEME FORINTENSITIES IN THE OPTIMAL SYMBOLIC ADDITION PROGRAM SIMPEL88

Application of Direct Methods to reflection intensities obtained by po wder diffraction is often obstructed by the fact that not all intensit ies are reliable. In this paper a weighting scheme is proposed to over come this problem. The scheme is implemented in the Direct Methods pro gram SIMPEL88 in such a way that phase relations containing overlappin g reflections are less probable than they would have been containing v ery reliable reflections only. Preliminary test results show that this way of tackling the problem is very promising.