| 11:26:19 AM PDT - Mon, Jul 8th 2013 |
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Hi Mahbub,
What you should be able to do is to calculate the potential energy surface of:
1. C-O
2. (C+)-(O-)
I.e. in the first set of calculations force the Carbon and Oxygen to have zero charge and in the second set of calculations force Carbon to have a +1 charge and the oxygen a -1 charge. Whether the results are a good representation of the physics you are trying to study is not immediately clear to me. What I do know is that you have to be a bit careful with the constrained DFT capability. This method adds a potential to the Hamiltonian to enforce the constraint that you apply. If the constrained electronic structure is far from what it would normally by this potential is large, which then distorts the electron distribution, which feeds back into the choice for the constraining potential. This feedback loop can lead to very aggressive constraining potentials and highly distorted electron densities, I have seen this happening in the past. So you may have to be careful to turn the constraints on in such a way as to not introduce unphysically large distortions. Apart from this the formalism should work...
Huub
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