Calculates electronic properties of molecules.
Hückel calculates the energy levels and molecular orbitals of a molecule using Hückel theory. Hückel is designed to provide an easy to use interface to Hückel theory. It uses an intuitive graphical interface which manages all of the input for the calculations.
Because it is very easy to do calculations with Hückel, there is more time to concentrate on other matters, such as the theory involved. The helpfile which comes with the program contains an extensive discussion of Hückel theory, and short biographies on Erich Hückel and Erwin Schrödinger.
Structural formula can be drawn in Hückel which serves as input to the calculation. From the structure formula, Hückel builds the matrices involved and performs the calculations. The resulting energy levels are presented in a level diagram, and a molecular orbital diagram shows the resulting molecular orbitals.
Advanced users will appreciate that Hückel provides access to all the results of the calculations involved. They may be readily output to the printer and/or copied to the Windows clipboard if desired. The number of atoms used in the calculations is virtually unlimited. The speed of the calculation will depend on the size of the molecule and on speed of your PC. With a 133 Mhz Pentium it takes about 45 seconds to calculate a molecule with 75 atoms. Hückel permits task switching during the calculations.
The atoms available in the structure formula editor are defined in a database. This database may be easily modified for custom applications. By allowing the definition of new atoms, the parameters involved in the Hückel calculations can be changed.