QuantumATK Forum

QuantumATK => General Questions and Answers => Topic started by: yongjunwinwin on July 11, 2011, 10:45

Title: A question about optimization
Post by: yongjunwinwin on July 11, 2011, 10:45

I have a few questions in doing structure optimization:
1.When should we constrain the cell and when we should untick the constrain, for example when I build a super cell, in which one carbon is substituted by other atoms or a molecule is absorbed on the surface of the graphene, whether should I constrain the cell or not in optimization.
2.If the case is not bulk material, but nanoribbon, what about the same problem mentioned above?

Title: Re: A question about optimization
Post by: zh on July 21, 2011, 03:18

If the chosen supercell is large enough, it is no necessary to optimize the lattice vectors of cell, and only the atomic positions should be optimized.