Quote:Edoapra May 21st 6:34 pmWhen using the Cs point group, NWChem assume the mirror plane being perpendicular to the z-axis (i.e. xy plane).
Therefore, you need to rotate the molecule to satisfy this constraint as shown here
geometry
N 0.0000 0.0000 0.0000
H -0.9377 -0.3816 0.0000
H 0.4689 -0.3816 0.8121
H 0.4689 -0.3816 -0.8121
symmetry cs
end
Thanks so much! This works now. However, I still have trouble for the methane molecule. The full point group is Td but it is also not Abelian. The Abelian subgroup is C2v. From the manual, in the C2v point group "the z axis is the C2 axis and the ?v may be either the xz or the yz planes". This is the input:
geometry
symmetry group c2v
C 0.0000 0.0000 0.0000
H 0.6276 0.6276 0.6276
H 0.6276 -0.6276 -0.6276
H -0.6276 0.6276 -0.6276
H -0.6276 -0.6276 0.6276
end
I checked in a graphics program. The z axis is the C2 axis and both xy and yz planes are the ?v. But the program still added 4 hydrogen atoms:
No. Tag Charge X Y Z
---- ---------------- ---------- -------------- -------------- --------------
1 C 6.0000 0.00000000 0.00000000 0.00000000
2 H 1.0000 0.62760000 0.62760000 0.62760000
3 H 1.0000 -0.62760000 -0.62760000 0.62760000
4 H 1.0000 0.62760000 -0.62760000 0.62760000
5 H 1.0000 -0.62760000 0.62760000 0.62760000
6 H 1.0000 0.62760000 -0.62760000 -0.62760000
7 H 1.0000 -0.62760000 0.62760000 -0.62760000
8 H 1.0000 0.62760000 0.62760000 -0.62760000
9 H 1.0000 -0.62760000 -0.62760000 -0.62760000
So what's wrong here?
Thanks very much.
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