Double crystallographic groups and their representations on the Bilbao Crystallographic Server

Understand

A new section of databases and programs devoted to double crystallographic groups (point and space groups) has been implemented in the Bilbao Crystallographic Server (http://www.cryst.ehu.es).

• The double crystallographic groups are required in the study of physical systems whose Hamiltonian includes spin-dependent terms.
• In the symmetry analysis of such systems, instead of the irreducible representations of the space groups, it is necessary to consider the single- and double-valued irreducible representations of the double space groups.
• The new section includes databases of symmetry operations (DGENPOS) and of irreducible representations of the double (point and space) groups (REPRESENTATIONS DPG and REPRESENTATIONS DSG).