On the handling of atomic anisotropic displacement parameters

A number of conventions for the parameterization of atomic anisotropic displacements are used in the literature and in crystallographic programs. Here we summarize the commonly used conventions, with a special emphasis on their application in macromolecular crystallography. We then describe a new software toolbox for the handling of the various parameterizations of atomic anisotropic displacements and their interconversion. All algorithms are integrated into the freely available Computational Crystallography Toolbox.