• crystal structure solution by powder diffraction data;
  • big bang–big crunch method;
  • global optimization;
  • simulated annealing;
  • EXPO;
  • computer programs

The big bang–big crunch method is a global optimization approach developed upon the analogy of one of the cosmological theories of the evolution of the universe. It has been suitably combined with a simulated annealing algorithm and used for solving crystal structure from powder diffraction data in direct space. When compared with the traditional simulated annealing method, it provides a significant advance: good solutions are attained in a shorter time. The new method has been implemented in the EXPO package. Its successful application is demonstrated with examples of already known structures.