Hanson Andrew J, Cheung Eugene Y, Harris Kenneth D M
School of Chemistry, Cardiff University, Park Place, Cardiff, CF10 3AT Wales, UK.
J Phys Chem B. 2007 Jun 14;111(23):6349-56. doi: 10.1021/jp070954c. Epub 2007 May 22.
A strategy is reported for assessing the feasibility of molecular conformations within direct-space structure-solution calculations of organic molecular crystal structures from powder X-ray diffraction data, focusing in particular on the genetic algorithm technique for structure solution in which fitness is defined as a function of the whole-profile figure-of-merit Rwp. The strategy employs a readily computed distance-based function to assess the feasibility of the molecular conformation in each trial structure generated in the genetic algorithm calculation, and structures considered to have low-feasibility conformations are penalized within the evolutionary process. The strategy is shown to lead to significant improvements in the success rate of structure-solution calculations in the case of flexible molecules with a significant number of conformational degrees of freedom.
报道了一种用于评估从粉末X射线衍射数据进行有机分子晶体结构直接空间结构解析计算中分子构象可行性的策略，特别关注结构解析的遗传算法技术，其中适应度被定义为全谱品质因数Rwp的函数。该策略采用一种易于计算的基于距离的函数来评估遗传算法计算中生成的每个试验结构中分子构象的可行性，并且在进化过程中对被认为具有低可行性构象的结构进行惩罚。结果表明，对于具有大量构象自由度的柔性分子，该策略可显著提高结构解析计算的成功率。
