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Re: Large GW gap
Posted: Sun Jun 05, 2011 8:50 am
by Daniele Varsano
Dear Shudong,
I do not know the dimension of your problem, anyway take in mind that
zcut:18-28, means an interaction range 9-14 a.u., (is this what you need?)
as stated in a previous post.
Other possibility is that your unit cell is not big enough.
Daniele
Re: Large GW gap
Posted: Sun Jun 05, 2011 9:25 am
by sdwang
Daniele Varsano wrote:Dear Shudong,
I do not know the dimension of your problem, anyway take in mind that
zcut:18-28, means an interaction range 9-14 a.u., (is this what you need?)
as stated in a previous post.
Other possibility is that your unit cell is not big enough.
Daniele
I test zcut 18-54, it also does not converge.
The vacuum thickness is 20 anstrugm.
Re: Large GW gap
Posted: Sun Jun 05, 2011 8:40 pm
by Daniele Varsano
Dear Shudong,
please read this
post for a correct use of the cutoff. Consider from the consideration you can find in the post if your cell and cutoff dimension are meaningfull: it also depend on the size of your system.
Cheers,
Daniele
Re: Large GW gap
Posted: Mon Jun 06, 2011 1:55 am
by sdwang
My 2 dimensional system along the nonperiodic direction z is abou 6 au, and the supercell lattice alone z is 38 au, so I chose zcut: 12<zcut<64 , but it not converge.