X-ray Analysis of Electron Density -Theory and Experiment-

点击翻译按钮获取中文摘要

The aim of the present international cooperative research is to exchange theoretical methods and experimental techniques in X-ray electron density study between researches in Russia and Japan and to Develop X-ray crystallography in the 21-st century. The methods of refinements of us in Japan and researchers in Russia are based on atomic or molecular orbitals (X-ray AO/MO analysis) and electron density (multiple refinement), respectively. The X-ray AO analysis has been successfully applied to transition metal complexes. However the X-ray MO analysis has not been successful.The electron density of perovskite KNiFィイD23ィエD2 crystals was studied because of the highest symmetry of the crystal field, in which both methods could be easily compared. It was analyzed with the both method and give almost the same electron configuration. Topological analysis of the electron density of KNiFィイD23ィエD2 revealed that the topological picture of the atomic interactions differed from that resulting from the classic crystal chemistry molecular orbital (CMO), in which the periodicity of crystals is taken into account, should be used.Highly accurate measurement is necessary for X-ray MO analysis. The VCIP method was devised to measure intensities free from the noise due to air-scattered X-rays. The VCIP measurement of KNiFィイD23ィエD2 was compared with that by a four-circle diffractometer. Both gave almost the same deformation density and R-factors were 0.4% and 0.8% for four-circle and VCIP measurements, respectively. Since slant incidence of diffracted X-rays onto IP and problems as a device for highly accurate intensity measurement in 21-st century.