[Pw_forum] Is the Graphite surface flate?
Dal Corso Andrea
dalcorso at sissa.it
Tue Jul 6 10:09:11 CEST 2010
On Mon, 2010-07-05 at 18:19 +0000, Masoud Nahali wrote:
> Dear Quantum Espresso users
>
> I optimized the graphite bulk and the layers were completely flat. But
> when I try to "relax" the graphite surface (slab 2*2 with 3 monolayer)
> with 10 angstrom vacuum all the layers become extremely ripple!!! I
> can not find the problem. May it related to the number of layers?
> anyhow the number of layers is like the bulk. Your help would be a
> great gift.
>
> input file:
>
> &CONTROL
> calculation = "relax",
> pseudo_dir = "/home/koa/soft/qe4.2/espresso-4.2/pseudo",
> outdir = "/home/koa/tmp",
> etot_conv_thr= 1.0D-4,
> forc_conv_thr= 1.0D-3,
> nstep=150,
> /
> &SYSTEM
> ibrav = 4,
> a = 4.9318,
> b = 4.9318,
> c = 16.7029,
> cosab = -0.5,
> cosac = 1.0,
> cosbc = 1.0,
> nat = 24,
> ntyp = 1,
> ecutwfc = 40.D0,
> ecutrho = 400.D0,
> occupations = 'smearing'
> smearing ='mp',
> degauss = 0.01,
> nspin = 2,
> starting_magnetization(1)= 1.0,
> /
> &ELECTRONS
> conv_thr = 1.D-6,
> mixing_beta = 0.7D0,
> diagonalization = "david",
> /
> &IONS
> ion_dynamics="bfgs"
> /
> ATOMIC_SPECIES
> C 12.0107 C.star1s-pbe-rrkjus.UPF
Check the pseudopotential. This is a PP with a core hole for special
purposes not for standard simulations.
HTH,
Andrea
> ATOMIC_POSITIONS {angstrom}
> C 0.000000 0.000000 0.000000
> C 2.465900 0.000000 0.000000
> C -1.232950 2.135532 0.000000
> C 1.232950 2.135532 0.000000
> C 0.000000 1.423688 0.000000
> C -1.232950 3.559220 0.000000
> C 2.465900 1.423688 0.000000
> C 1.232950 3.559220 0.000000
> C 0.000000 0.000000 3.351450
> C 2.465900 0.000000 3.351450
> C -1.232950 2.135532 3.351450
> C 1.232950 2.135532 3.351450
> C 1.232950 0.711844 3.351450
> C 0.000000 2.847376 3.351450
> C 3.698850 0.711844 3.351450
> C 2.465900 2.847376 3.351450
> C 0.000000 0.000000 6.702900
> C 2.465900 0.000000 6.702900
> C -1.232950 2.135532 6.702900
> C 1.232950 2.135532 6.702900
> C 0.000000 1.423688 6.702900
> C -1.232950 3.559220 6.702900
> C 2.465900 1.423688 6.702900
> C 1.232950 3.559220 6.702900
> K_POINTS {automatic}
> 4 4 1 1 1 1
>
>
> out put (optimized positions):
>
> C 0.000000000 -0.000000000 -0.686394528
> C 2.465900000 -0.003714144 -0.758610095
> C -1.229733457 2.137389072 -0.758610095
> C 1.229733457 2.137389072 -0.758610095
> C 0.000000000 1.427474855 -0.213813075
> C -1.229670488 3.557326573 -0.213813075
> C 2.465900000 1.423688000 -0.285079086
> C 1.229670488 3.557326573 -0.213813075
> C -0.000000000 0.000000000 3.630366631
> C 2.465900000 -0.014904710 3.544792504
> C -1.220042143 2.142984355 3.544792504
> C 1.220042143 2.142984355 3.544792504
> C 1.220249305 0.704511250 3.106073641
> C 0.000000000 2.847376000 3.022325711
> C 3.711550695 0.704511250 3.106073641
> C 2.465900000 2.862041499 3.106073641
> C 0.000000000 0.000000000 7.468882932
> C 2.465900000 0.008344370 7.466151214
> C -1.240176436 2.131359815 7.466151214
> C 1.240176436 2.131359815 7.466151214
> C 0.000000000 1.414904155 6.963129179
> C -1.240557033 3.563611923 6.963129179
> C 2.465900000 1.423688000 6.961528237
> C 1.240557033 3.563611923 6.963129179
>
>
>
> Many Thanks
> Masoud Nahali
> Sharif University of Technology
>
>
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--
Andrea Dal Corso Tel. 0039-040-3787428
SISSA, Via Beirut 2/4 Fax. 0039-040-3787528
34151 Trieste (Italy) e-mail: dalcorso at sissa.it
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