mopac

Semi-empirical (MNDO, etc.) molecular orbital calculation

MOPAC (Molecular Orbital PACkage) is a powerful computational chemistry software that employs semi-empirical quantum chemistry methods to study molecular and periodic structures. Developed since 1981, it offers a balance of computational speed and accuracy for a wide range of applications in chemistry and materials science. MOPAC implements various semi-empirical models, including AM1, PM3, PM6, and PM7. It performs geometry optimization, transition-state optimization, and vibrational analysis. Key features include solvation models (COSMO), support for periodic boundary conditions, and the unique MOZYME solver for rapid calculations on large systems, such as biomolecules and materials. MOPAC also calculates gas-phase thermodynamics, molecular polarizability, and integrates with numerous graphical user interfaces and other chemistry software. It supports 83 elements of the periodic table.