Translation functions: the minimization of structure-independent spurious maxima

A procedure is described whereby the magnitudes of the structure-independent spurious maxima produced by translation syntheses are minimized. The new method has the advantage that it is applicable to all space groups. Structure-dependent spurious maxima are not as markedly reduced by the new method, but may be confidently suppressed by means of previously described procedures. Translation syntheses for which both sources of spurious maxima have been treated generally possess fewer strong peaks and flatter backgrounds. Trial calculations for test fragments comprising about half of the contents of the asymmetric unit typically produce a single solution vector which may be enhanced to ten times the magnitude of the next largest maxima. The usefulness of these procedures appears to diminish rapidly once the size of the search fragment is reduced to less than a quarter of the contents of the asymmetric unit. The solution vector may not be the largest maxima produced by these smaller fragments, but the translation maps will possess far fewer sizable spurious maxima to be confused with the solution vector than maps which have not been treated to reduce these spurious maxima.