CAChe MOPAC

The CAChe MOPAC package is a comprehensive semi-empirical, quantum mechanical calculation for valence electrons. This technique includes methods to optimize the geometry of your molecule as well as methods to give information concerning the location of electron density within your system.

CAChe MOPAC can utilize either PM3 or AM1 parameters.
CAChe MOPAC has AM1 parameters for H, B, C, N, O, F, Al, Si, P, S, Cl, Zn, Ge, Br, I and Hg.
CAChe MOPAC has PM3 parameters for H, Li, Be, C, N, O, F, Mg, Al, Si, P, S, Cl, Zn, Ga, Ge, As, Se, Br, Cd, In, Sn, Sb, Te, I, Hg, Tl, Pb and Bi.

MOPAC calculations give you information concerning the optimized geometry of your molecule, the frontier molecular orbitals, electron density distribution, partial charges, dipole moment, bond order, ionization potentials, electron affinities and vibrational spectra. This technique is slower than the Extended Huckel and ZINDO calculations. The results of the MOPAC calculations can be shown with your molecule in the chemical sample window.

CAChe references:
Bingham, R. C., Dewar, M. J. S., Lo, D. H., J. Am. Chem. Soc. 1975, 97, 1294.
Healy, E. F., Stewart J. J. P., J. Am. Chem. Soc. 1985, 107, 3902.
Stewart, J. J. P., J. Comp. Chem. 1989, 10, 209.

Detailed information on Molecular Modeling is available at the NIH Molecular Modeling Home Page