I have since discovered that this site: http://openmopac.net/ is up, and contains chapter and verse on MOPAC 7.1/2 (as the new code appears to be called). There is a link for source code for 7.1, and executable for 7.2 -- Henry Rzepa. +44 (020) 7594 5774 (Voice); +44 (0870) 132 3747 (eFax); rzepahs at mac.com (iChat) http://www.ch.ic.ac.uk/rzepa/ Dept. Chemistry, Imperial College London, SW7 2AZ, UK. (Voracious anti-spam filter in operation for received email. If expected reply not received, please phone/fax).