Computer programs AMPAC

Semi-empirical methods, such as AMI, MINDO/3 and PM3, implemented in programs like MOPAC, AMPAC, HyperChem, and Gaussian, use parameters derived from experimental data to simplify the computation. They solve an approximate form of the Schrodinger equation that depends on having appropriate parameters available for the type of chemical system under investigation. Different semi-emipirical methods are largely characterized by their differing parameter sets. 

CODESSA is a fully featured QSAR/QSPR program the primary purpose of which is to tie experimental information to quantum mechanical results, and use the resulting correlations to predict the properties and activities of molecules for which no experimental results exist. To this end, CODESSA can compute over 500 descriptors from an AMPAC results file and correlate these descriptors with provided experimental data using several advanced statistical techniques. 

---