Rietveld refinement with wavelet compressed data sets

Crystal structures of highly ordered triclinic kaolinite, cubic hexamethyle ntetramine and a part of the structure of monoclinic rare sugar were refine d by Rietveld method using wavelet compressed sets of intensities. Compress ion of intensities sets was accomplished by a discrete wavelet transform (D WT). It was found that accuracy of refined positional parameters did not ch ange significantly even if the compression ratio reached 8:1. Similarly, qu antitative phase analysis done by Rietveld method provided very close estim ates of phase composition for compression ratios 2:1 and 4:1. Application of DWT compressed data led to time savings approaching 50-60% w ithout significant loss of information. This procedure may accelerate molec ular modelling based on powder data, or speed up introductory steps of Riet veld refinements with extensive data/parameters sets.