[Pw_forum] van der waals force

[Mehrnaz Anvari]

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Dear paulatto

Thanks a lot because of your attention.
I want to put graphene on substrate so I think that the van der waals
force becomes important for this case (isn't correct?). By the way I have
read the paper of M.Lazzeri & et al(Phys. Rev. B 78,
081406(R) (2008)) & I know the problem of  LDA & GGA
approximations(for graphene & graphite), so if  there is any way to correct 
them please aware
me.

Well, I have to explain more about my
first question. please assume that we have two layers of graphene.
First the distance between them is 3 a.u & then it has been
changed to 10 a.u. What will happen for hartree(Uee) term in
calculations, Do you expect that it will increase or decrease?

Best Regards

Mehrnaz Anvari

Iran University Of Science &
Technology
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