SUBGROUPGRAPH: a computer program for analysis of group–subgroup relations between space groups

摘要: Group±subgroup relations between two space groups, G > H, are of essential importance for phase-transition problems: determination the relation lowand high-symmetry structures, domain structure analysis, displacement-mode etc. The available subgroup data in International Tables Crystallography, Vol. A (1995), not suf®cient a detailed treatment H relations. necessary will be forthcoming A1 Crystallography (2001). program SUBGROUPGRAPH uses preliminary CIF version database (Wondratchek et al., 1996). main aim is study group±subgroup including construction chains maximal subgroups speci®ed/non-speci®ed index i = |G:H| (the so-called G±H graph), number different Hk < G,  and their distribution into classes conjugate relative to