From NWChem
Viewed 1829 times, With a total of 2 Posts
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Clicked A Few Times
Threads 15
Posts 31
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| 9:53:47 AM PDT - Mon, Jun 23rd 2014 |
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Hi,
I use the exact same example given in the documentation to try the ONIOM calculation, but it gave me an error saying :
oniom: model does not have correct symmetry 0
------------------------------------------------------------------------
There is an error related to the specified geometry
------------------------------------------------------------------------
This is the input file:
start
basis spherical
H library 6-311++G**; C library 6-311++G**
end
title "ONIOM Me-CH2"
geometry autosym
H -0.23429328 1.32498565 0.92634814
H -0.23429328 1.32498565 -0.92634814
C -0.13064265 0.77330370 0.00000000
H -1.01618703 -1.19260361 0.00000000
H 0.49856072 -1.08196901 -0.88665533
H 0.49856072 -1.08196901 0.88665533
C -0.02434414 -0.71063687 0.00000000
end
scf; uhf; doublet; thresh 1e-6; end
mp2; freeze atomic; end
oniom
high mp2
low scf
model 3 3 7 0.724
end
task oniom
title "ONIOM Me-Me"
geometry # Note cannot use full D3D symmetry here
H -0.72023641 0.72023641 -1.16373235
H 0.98386124 0.26362482 -1.16373235
H -0.26362482 -0.98386124 -1.16373235
C 0.00000000 0.00000000 -0.76537515
H 0.72023641 -0.72023641 1.16373235
H -0.98386124 -0.26362482 1.16373235
H 0.26362482 0.98386124 1.16373235
C 0.00000000 0.00000000 0.76537515
end
scf; rhf; singlet; end
oniom
high mp2
low scf
model 4 4 8 0.724
end
task oniom
Has anyone encountered the same problem ?
Thanks in advance for your help.
Regards,
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Huub Forum:Admin, Forum:Mod, NWChemDeveloper, bureaucrat, sysop
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Forum Regular
Threads 1
Posts 185
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| 6:09:49 PM PDT - Tue, Jun 24th 2014 |
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Hi Mhiranya,
Thank you for spotting this problem. Actually it turns out that the example was out-of-date. Judging by the presence of the "autosym" keyword on the first geometry this example must date back to a time when automatic symmetry detection was not the default behavior of the code. Hence in those days no symmetry would be used with the second geometry.
This behavior has been changed years ago. Now the code always tries to automatically detect symmetry, unless instructed otherwise. This leads it to find the incorrect D3D symmetry for the second geometry. So, now we need to explicitly intervene and lower the symmetry to get the correct behavior. Specifying the second geometry as
H -0.72023641 0.72023641 -1.16373235
H 0.98386124 0.26362482 -1.16373235
H -0.26362482 -0.98386124 -1.16373235
C 0.00000000 0.00000000 -0.76537515
H 0.72023641 -0.72023641 1.16373235
H -0.98386124 -0.26362482 1.16373235
H 0.26362482 0.98386124 1.16373235
C1 0.00000000 0.00000000 0.76537515
does just that. With this change the input will correctly.
I have updated the manual accordingly.
Best wishes, Huub
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Clicked A Few Times
Threads 15
Posts 31
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| 8:04:04 PM PDT - Thu, Jul 10th 2014 |
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Hi Huub,
So, this means you have changed the label or so ...
C1 0.00000000 0.00000000 0.76537515
Thanks
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