44 巻 (2002) 6 号 p. 380-388
The combination of RIETAN-2000 and a new MEM analysis program PRIMA enables us to represent crystal structures with densities of electrons (X-ray diffraction) or coherent-scattering lengths (neutron diffraction) instead of structure parameters in Rietveld analysis. We have devised sophisticated methodology named MEM-based pattern fitting, where whole-pattern fitting and MEM analysis are alternately repeated to reduce the bias of a structural model in Rietveld analysis as much as possible. Applications of MPF to some compounds will be demonstrated. A 3D visualization program VENUS serves to display and manipulate electron and scattering-length densities, electrostatic potentials, wave functions, and so forth.