The program system Crunch may be downloaded freely. However, copying, modification and distribution of the system without express written permission by the authors is strictly forbidden. Within the context of non-profit research in educational establishments the system may be used free of charge. Prospective commercial users are required to contact the Leiden Institute of Chemistry, Leiden University at the address given above in order to arrive at a suitable arrangement. At no time, now or in the future, will the possibility of free downloading of the software invalidate the intellectual property rights to this software, currently held by the Leiden University, Leiden, The Netherlands