Molecular packing groups and ab initio crystal-structure prediction.
Ab initio crystal structure prediction can proceed by minimization of the packing energy of Z independent molecules per cell, or alternatively by energy minimization taking one molecule as independent and Z - 1 molecules as related by assumed space-group symmetry. In the former method, a large number of positional variables must be considered. In the latter method, a large number of space groups must be considered. An alternative, more efficient, procedure is proposed, where it is recognized that values of Z and the number of molecules in the asymmetric unit, Z', impose restrictions on possible space groups. Examples of application of this method to crystal structure prediction are given.
Department of Chemistry, University of Louisville, Louisville, KY 40292, USA.
D
Gao
DE
Williams