Defining cyclobutadiene

Victor Manuel Rosas-García quimico69@yahoo.com
Mon, 1 Mar 1999 14:35:51 -0800 (PST)


Hello everybody,

I've bee trying to define ciclobutadiene but I always get an error
message.  The definition file is:

name = 'ciclobutadieno'

C1 = Atom('C')
H1 = Atom('H')
H2 = Atom('H')
H3 = Atom('H')
H4 = Atom('H')
C2 = Atom('C')
C3 = Atom('C')
C4 = Atom('C')
    
bonds = [Bond(C2, C1), Bond(C3, C2), Bond(C4, C3), 
         Bond(H1, C1), Bond(H2, C2), Bond(H3, C3), Bond(H4, C4)]

configurations = {
	'default': ZMatrix([[C1],
	                    [H1, C1,  0.9*Ang],
	                    [H2, C2,  0.9*Ang,  C1,  120.0*deg],
	                    [H3, C3,  0.9*Ang,  C2,  120.0*deg,  C1, 
180.0*deg], 
	                    [H4, C4,  0.9*Ang,  C3,  120.0*deg,  C2, 
180.0*deg],
	                    [C2, C3,  1.4*Ang,  C4,   90.0*deg,  C1,   
0.0*deg],
	                    [C3, C4,  1.4*Ang,  C1,   90.0*deg,  C2,   
0.0*deg],
	                    [C4, C1,  0.9*Ang,  C2,   90.0*deg,  C3,   
0.0*deg]])
	                    
	}

then I start the python interpreter and run as follows:


Python 1.5.1 (#2, Jan 12 1999, 19:13:08) [C] on aix4
Copyright 1991-1995 Stichting Mathematisch Centrum, Amsterdam
>>> from mmtk import *
>>> d = Molecule('ciclobutadieno')
Traceback (innermost last):
  File "<stdin>", line 1, in ?
  File "/usr/local/mmtk/ChemicalObjects.py", line 405, in __init__
    CompositeChemicalObject.__init__(self, properties)
  File "/usr/local/mmtk/ChemicalObjects.py", line 116, in __init__
    self.configurations['default'].applyTo(self)
  File "/usr/local/mmtk/ConfigIO.py", line 185, in applyTo
    self.findPositions()
  File "/usr/local/mmtk/ConfigIO.py", line 158, in findPositions
    pos1 = self.coordinates[self.data[2][1]]
KeyError: <Atom number 1>


Any ideas as to what's wrong?  

Note: in my group, we are in the process of becoming Python experts,
but still are far from that, :(.

Thanx

Victor


==
Victor M. Rosas García
Computational Chemistry Apprentice

e-mail: quimico69@yahoo.com

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