[Pw_forum] carbon nanotube & copper chain

Nicola Marzari marzari at MIT.EDU
Fri Jun 18 08:59:28 CEST 2010

Dear Yang,

1) start from something much simpler. you need to build some competence,
or you'll get meaningless results. study diamond, graphite, graphene,
and a few perfect nanotubes first. compare with literature.

2) contrary to what is said below, you CAN mix ultrasoft and norm-conserving

3) for a isolated tube, use indeed a sampling 1 1 n, with n integer - 
but keep
in mind that then the nanotube needs to be infinite in the z direction. 
if infinite
along x, you need n 1 1 (and then a shift that is 1 1 1 or 0 0 0 or 1 0 
0). there is
no difference between a 1 0 0 shift and a 1 1 1 shift, for a tube along 
x. why ?


xirainbow wrote:
> Dear Yang:
> 1:Why you choose C.pz-vbc.UPF and Cu.pz-d-rrkjus.UPF.
> Cu.pz-d-rrkjus.UPF is Ultrasoft pseudopotential
> However, C.pz-vbc.UPF is  Norm - Conserving pseudopotential.
> You should set all atoms to the same kind of PP.
> 2:Kpoints:4 4 4   1 1 1 
> If you are going to deal with isolated nanotube,
> you should set Kpints to 1 1 X. X is a integer.
> On Fri, Jun 18, 2010 at 8:42 AM, chengyu yang <chengyu.young at gmail.com 
> <mailto:chengyu.young at gmail.com>> wrote:
>     Dear everyone,
>           i am trying to creat a carbon nanotube with a cu chain in
>     its center, but i am not sure if my parameter settings are
>     correct:I don't know if under the &system item, i should use the
>     only cnt's data, and i am not sure the setting of k points.
>     Because it will cost a lot of time to calculate, I want to make it
>     as correct as possible. Would you plz have a look at my script and
>     give some suggestions?Thank you.
>          As following:

Prof Nicola Marzari   Department of Materials Science and Engineering
13-5066   MIT   77 Massachusetts Avenue   Cambridge MA 02139-4307 USA
tel 617.4522758 fax 2586534 marzari at mit.edu http://quasiamore.mit.edu 

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