THIS INFORMATION IS OBSOLETE AND IS PROVIDED ONLY FOR ITS HISTORICAL VALUE

This version of MOPAC will only execute on an IBM-PC which is equipped with the special ÆON 32-bit board.

MOPAC is a general-purpose semiempirical molecular-orbital package for the study of chemical reactions. The semiempirical Hamiltonians MNDO, MINDO/3 and AM1 are implemented; and calculations of vibrational spectra, thermodynamic quantities, isotopic substitution effects and force constants for molecules, ions and radicals are combined in a fully integrated package. One limitation is that RHF radicals cannot be used with FORCE in the default set of options. However, users can run RHF radicals with FORCE if the maximum number of allowed atoms is reduced. Within the electronic part of the calculations, eigenvectors and localized orbitals, chemical bond indices, charges, molecular orbitals, etc. are calculable. For studying chemical reactions, a transition- state location routine and a transition-state optimizing routine are available.For potential users to get the most out of the program, they must understand how the program works, how to enter data, how to interpret the results--and what to do when things go wrong.

While MOPAC calls upon many concepts in quantum theory and thermodynamics and uses some fairly advanced mathematics, the user who is not familiar with these specialized topics should not feel excluded from using it. On the contrary, MOPAC is written with the non-theoretician in mind, To this end, the data are kept as simple as possible; this means that users can give their attention to the chemistry involved and not concern themselves with quantum and thermodynamic exotica.

In addition to the Æon 032/PC board, one needs a 40 Mb or larger hard disk as well as DOS 2.0 or higher, UNIX System V (Version 2, release 2 or higher) and the standard UNIX FORTRAN 77 compiler.

This version of MOPAC is capable of handling up to 38 heavy atoms and 38 light atoms.

FORTRAN 77 Lines of Code: 18,000