From NWChem
Viewed 1965 times, With a total of 2 Posts

Clicked A Few Times
Threads 15
Posts 31


8:53:47 AM PDT  Mon, Jun 23rd 2014 

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 6311++G**; C library 6311++G**
end
title "ONIOM MeCH2"
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 1e6; end
mp2; freeze atomic; end
oniom
high mp2
low scf
model 3 3 7 0.724
end
task oniom
title "ONIOM MeMe"
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,




Huub Forum:Admin, Forum:Mod, NWChemDeveloper, bureaucrat, sysop


Forum Regular
Threads 1
Posts 185


5:09:49 PM PDT  Tue, Jun 24th 2014 

Hi Mhiranya,
Thank you for spotting this problem. Actually it turns out that the example was outofdate. 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




Clicked A Few Times
Threads 15
Posts 31


7:04:04 PM PDT  Thu, Jul 10th 2014 

Hi Huub,
So, this means you have changed the label or so ...
C1 0.00000000 0.00000000 0.76537515
Thanks



AWC's:
2.5.10 MediaWiki  Stand Alone Forum Extension
Forum theme style by: AWC