Method of crystal-structure similarity searching

Abstract

An algorithm is presented which is used to recognize the similarity of crystal structures by matching a description of one structure against the equivalent descriptions of a second. Equivalent descriptions are considered since there are multiple possible ways of choosing the crystal axes and their origin, the asymmetric unit and atom numbering. Another idea used in the algorithm is to use positional and rotational parameters of the molecular fragments to describe the principal crystal structure. The two structures are considered to be similar if in such descriptions the corresponding cell parameters and the parameters of corresponding fragments differ from each other within the limits specified