CAChe Extended Huckel

The CAChe Extended Huckel calculation package is a semi-empirical, quantum mechanical calculation. This is an all valence electron approximation to solving the Schrodinger equation. CAChe supplies an Extended Huckel parameter set but you can also input other parameter sets to customize your calculations. This method allows you to calculate the position of valence electrons in your molecule. This method is parameterized for all elements in the periodic table. This method does not provide any information about the optimized geometry of your system. Extended Huckel calculations give you information concerning the frontier molecular orbitals, electron density distribution, partial charges, dipole moment and bond order. The results of these calculations can be displayed over your molecule in the chemical sample window. This is the fastest quantum mechanical calculation on the CAChe system but does not provide any information about the geometry of your system.

CAChe references:
R. Hoffman, J. Chem. Phys. 1963, 39, 1397.

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