Palatinus Lukáš, Fleischer Frank, Pattison Phillip, Weber Thomas, Steurer Walter
Institute of Physics, Academy of Sciences of the Czech Republic, Na Slovance 2, 182 21 Prague, Czech Republic.
Acta Crystallogr A. 2011 Jan;67(Pt 1):9-20. doi: 10.1107/S0108767310041437. Epub 2010 Nov 11.
The charge-flipping algorithm in its band-flipping variant is capable of ab initio reconstructions of scattering densities with positive and negative values. It is shown that the method can be applied to reconstructions of difference electron densities of superstructures, i.e. densities obtained as a difference between the true scattering density and the average density over two or more subcells of the true structure. The amplitudes of reflections lying on the reciprocal lattice of the subcell are not required for the procedure. A series of examples shows applications of the method to the solution of superstructures in periodic crystals or quasicrystals as well as the application to ab initio solution of modulation of an incommensurately modulated structure from satellite reflections only and solution of a structure from a crystal twinned by reticular pseudomerohedry. The method is especially suited for solving pseudosymmetry problems occurring frequently in superstructures.
带翻转变体的电荷翻转算法能够从头开始重建具有正值和负值的散射密度。结果表明，该方法可应用于超结构的差分电子密度重建，即作为真实散射密度与真实结构的两个或多个子晶胞上的平均密度之差获得的密度。该过程不需要子晶胞倒易晶格上反射的振幅。一系列示例展示了该方法在周期性晶体或准晶体中超结构求解中的应用，以及仅从卫星反射对非相称调制结构的调制进行从头求解和从网状假等轴孪晶晶体求解结构的应用。该方法特别适用于解决超结构中频繁出现的假对称问题。
