In case the list is wondering about this deluge, these are all issues that emerged during the writing of http://www.ch.ic.ac.uk/wiki/index.php/Second_Year_Modelling_Workshop Some force fields do allow (primitive) solution of Huckel equations to estimate the pi resonance energy as a contribution to the total steric energy. does anyone know if this is a feature of Tripos 5.2? 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). _______________________________________________ ghemical-devel mailing list ghemical-devel at bioinformatics.org http://bioinformatics.org/mailman/listinfo/ghemical-devel -- 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).