I developed a program, which might be of interest for those who prefer
to write there Z-matrices by hand.
One of the mayor disadvantages of using a conventional Z-matrix as an input
for Mopac-calculations is the necessity to keep track of the numbering of
the used atoms. This can get quite tricky in case of very large molecules.
Another problem frequently encountered is if one wants to substitute parts
of a molecule by other substituents.
The program enables the user to split a molecule into fragments, defining
the Z-matrix for each fragment separately and putting fragments together by
defining postions of a fragment relative to another fragment. (Hope everyone
understands what I mean)
Also it is possible to use an archive of fragments, so that frequently used
groups (e.g. methyl of phenyl) can be incorporated easily.
Another application would be the study of a complex of two molecules or
a molecule surrounded by a solvent.
The benefits of the program are:
o The construction of a Z-matrix even for larger molecules is much easier,
without recoursing to computer programs like PC-model.
o Substituting fragments of a molecule by different fragments, does not
require a recalculation of the referenced atomsnumbers. Also the atoms
of a fragment are not spread over the whole input-file.
o By using an archive of fragments, it is not necessary to reconstruct
frequently needed fragments again and again. (e.g. Methyl- or
The program is written in C and was tested on a PC an a workstation.
Whoever is interested in this program can get it from me.
Just send a letter and I will post the source-code.
FAX 09131 - 858307
E-mail : PC1-0at0-cnve.rrze.uni-erlangen.dbp.de