Description
This method keyword requests an extended Huckel calculation [ Hoffmann63 R. Hoffmann, “An Extended Huckel Theory. I. Hydrocarbons,” J. Chem. Phys., 39 (1963) 1397. DOI: , Hoffmann64 R. Hoffmann, “An Extended Huckel Theory. II. Sigma Orbitals in the Azines,” J. Chem. Phys., 40 (1964) 2745. DOI: , Hoffmann64a R. Hoffmann, “An Extended Huckel Theory. III. Compounds of Boron and Nitrogen,” J. Chem. Phys., 40 (1964) 2474. DOI: , Hoffmann64b R. Hoffmann, “An Extended Huckel Theory. IV. Carbonium Ions,” J. Chem. Phys., 40 (1964) 2480. DOI: , Hoffmann66 R. Hoffmann, “Extended Huckel Theory. V. Cumulenes, Polyenes, Polyacetylenes and Cn,” Tetrahedron, 22 (1966) 521. DOI: ]. ExtendedHuckel is a synonym for this keyword. No basis set keyword should be specified.
オプション
Options
Hoffmann
Requests an Extended Huckel calculation using the default parameter set from the Huckel group.
Muller
Requests an Extended Huckel calculation using parameters collected by Edgar Muller.
Guess
Requests an Extended Huckel calculation using the modified parameters used for Guess=Huckel [ Pyykko81 P. Pyykko and L. L. Lohr, “Relativistically Parameterized Extended Huckel Calculations. 3. Structure and Bonding for Some Compounds of Uranium and Other Heavy-Elements,” Inorganic Chem., 20 (1981) 1950-59. DOI: , Pyykko84 P. Pyykko and L. Laaksonen, “Relativistically Parameterized Extended Huckel Calculations. 8. Double-Zeta Parameters for the Actinoids Th, Pa, U, Np, Pu, and Am and an Application on Uranyl,” J. Phys. Chem., 88 (1984) 4892-95. DOI: , Fitzpatrick86 N. J. Fitzpatrick and G. H. Murphy, “Double Zeta-D Radial Wave-Functions for Transition-Elements,” Inorg. Chim. Acta, 111 (1986) 139-40. DOI: ].
適用範囲
Availability
Energies, “analytic” gradients, and numerical frequencies.
実例
Examples
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.
関連キーワード
Related Keywords