Evaluation of Reflection Intensities for the Components of Multiple Laue Diffraction Spots by the Maximum-Entropy Method

Abstract

In a Laue diffraction pattern, 10-20% of the spots result from the exact superposition of two or more reflections that are 'harmonics'; a high proportion of these are low-resolution reflections. For the solution of large or difficult structural problems, the intensities of the remaining 80-90% of the reflections, measurable as singles, may not be sufficient and thus the evaluation of the intensities of the components of the multiple spots is important. A new method for this deconvolution is presented that is based on maximizing the entropy of the Patterson function subject to the constraints imposed by the observed intensities of single and overlapping reflections. This method does not require data redundancy and therefore is of particular interest for time-resolved studies on a short time scale. A new computer program (ME) was implemented and tested with Laue diffraction data from hen egg white lysozyme. The R factor between the deconvoluted reflection intensities from Laue multiple spots and observed intensities from monochromatic data was 0.116.