[Pw_forum] Fwd:NMR of benzene

[nlu at mail.ustc.edu.cn]

>From: "" <nlu at mail.ustc.edu.cn>
>Reply-To: "" <nlu at mail.ustc.edu.cn>
>To: pw_forum at pwscf.org
>Subject: NMR of benzene
>Date:Fri, 07 Aug 2009 21:22:14 +0800
>
>Dear all,
> I have used GIPAW to calculate NMR of benzene recently. I have two question,
the
> first is why the mass of diamond C is 12 in the input file, in the examples of
> GIPAW, why not 13? 
> The second is something strange happened in my calculation. When I increase the
> ecutwfc, the shielding tensor of C did not converge:
> 40ry:43ppm. 50ry:40ppm. 60ry:46ppm. 70ry:55ppm. 80ry:54ppm. 90ry: 43ppm.
> 100ry:30ppm. 110ry:27ppm. 120ry:39ppm. 130ry:62ppm. 140ry:85ppm.
> The input file is as following:
> scf.in
> &control
>     calculation='scf',
>     prefix='ben40',
>     tstress = .true.,
>     tprnfor = .true.,
>     restart_mode='from_scratch',
>     pseudo_dir ='/home/ustc/zyli/LuNing/NMR/pseudo',
>     outdir='/tmp/',
>     wf_collect = .true.
>  /
>  &system
>     ibrav=  0, celldm(1) = 1.889725989,
>     nat= 12, ntyp= 2,
>     nbnd= 50,
>     ecutwfc = 40, ecutrho = 160,
>     spline_ps = .true.
>  /
>  &electrons
>     diagonalization = 'david'
>     mixing_mode = 'plain'
>     mixing_beta = 0.4
>     conv_thr = 1.0d-10
>  /
> ATOMIC_SPECIES
>  C  12.0107  C.pbe-tm-gipaw.UPF
>  H  1.00794  H.pbe-tm-gipaw.UPF
> CELL_PARAMETERS
>    15.000000     0.000000     0.000000
>     0.000000    15.000000     0.000000
>     0.000000     0.000000    10.000000
> K_POINTS (automatic)
>  1 1 1 0 0 0
> ATOMIC_POSITIONS (crystal)
> C  0.7308956360000001  0.9405381680000000  1.1476448430000001
> C  0.8213534039999999  0.9418137320000000  1.1835869040000000
> C  0.8707671719999998  0.8623363860000000  1.1842830870000001
> C  0.8297234940000000  0.7815763499999999  1.1490365249999999
> C  0.7392633260000001  0.7803012599999999  1.1130950639999999
> C  0.6898517000000000  0.8597802960000001  1.1123997629999998
> H  0.6194515180000000  0.8587884660000000  1.0844271930000002
> H  0.6924443960000000  1.0023908619999999  1.1471064960000001
> H  0.8532991100000000  1.0046622900000000  1.2110162340000004
> H  0.9411691480000000  0.8633331299999999  1.2122536769999999
> H  0.8681772059999999  0.7197198679999999  1.1495745989999999
> H  0.7073118900000002  0.7174531920000000  1.0856646179999998
> nmr.in
> &inputgipaw
>         job = 'nmr'
>         prefix = 'ben40'
>         tmp_dir = '/tmp/'
>         isolve = 0
>         iverbosity = 1
>         q_gipaw = 0.01
>         spline_ps = .true.
>         use_nmr_macroscopic_shape = .true.
> /
> I have already tested the supercell and the number of k-points. They are all
> enough. Can someone tell the reason or the mistake of my calculation? 
>                                                                  Thanks,  Ning
Lu
> 
> 
>