doing Hueckel calculations is a fine feature of the Marvin software.
I can reproduce the results as I know it from my programs here.
Now my questions.
1) Where can I find a table of the hetero-parameters Marvin is using ?
2) For which atoms can I use the Hueckel calculations ? Is that automatically restricted ? Such as the restriction for "Aromatic systems".
Marvin's parameter set based on this reference:
Neil S. Isaacs, Physical Organic Chemistry, John Wiley & Sons, Inc., New York, 1987.
The large part of the parameters were developed by us "in house".
An additional reference for Hückel's parameters: A. Streitwieser, Molecular Orbital Theory for Organic Chemists, John Wiley, 1961.
Depending on the chemical environment the next atoms have optimal Coulomb and resonance integral parameters built into the Marvin.
All other atom has a default not optimized parameter.
the "Isaacs"-book is out of print. And in our three large libraries here in Munich there is only one exemplar of the 1995 edition. I hope I will get it after February 13th.
The "Streitwieser" is nearby my computer and I use it since 1970.
By calculating with Marvin fulven and formaldehyd it is easy to find that Marvin is using the standard parameter for C=C and C=O (Streitwieser page 135).
My point is: For use in scientific papers and for teaching computer chemistry you must
have full references for your results. In this case complete references for the calculation method and the parameters.
I suggest, that you will post these references in a link "More Information" in the description of the Huckel Analysis Plugin http://www.chemaxon.com/marvin/help/calculations/calculator-plugins.html#huckel
So one can cite this page as a reference.