Defining cyclobutadiene

[Konrad Hinsen]

> configurations = {
> 	'default': ZMatrix([[C1],
> 	                    [H1, C1,  0.9*Ang],
> 	                    [H2, C2,  0.9*Ang,  C1,  120.0*deg],

There's the problem. Each line in a Z Matrix defines the position of
one atom in terms of the positions of *previously* defined atoms. But
you are trying to define H2 in terms of C2, which has not been
assigned a position before!

>   File "/usr/local/mmtk/ConfigIO.py", line 158, in findPositions
>     pos1 = self.coordinates[self.data[2][1]]
> KeyError: <Atom number 1>

The error message isn't quite clear, I'll see if I can provide
something more specific.

Konrad
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Konrad Hinsen                            | E-Mail: hinsen@cnrs-orleans.fr
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