This method keyword requests an extended Huckel calculation [Hoffmann63, Hoffmann64, Hoffmann64a, Hoffmann64b, Hoffmann66]. ExtendedHuckel is a synonym for this keyword. No basis set keyword should be specified.
Requests an Extended Huckel calculation using the default parameter set from the Huckel group.
Requests an Extended Huckel calculation using parameters collected by Edgar Muller.
Requests an Extended Huckel calculation using the modified parameters used for Guess=Huckel [Pyykko81, Pyykko84, Fitzpatrick86].
Energies, “analytic” gradients, and numerical frequencies.
The energy appears in the output file as follows (followed by the x, y, and z components of the dipole moment):
Huckel eigenvalues -- -1.245 -0.637 -0.558 -0.544 -0.043 0.352 Energy= -5.968836513622 NIter= 0. Dipole moment= 0.000000 0.000000 0.000000
The energy is as defined by this semi-empirical model. Note that energy differences computed from the values in semi-empirical calculations are in Hartrees and may be compared directly with energy differences computed from jobs using other methods.
Last updated on: 05 January 2017. [G16 Rev. C.01]