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<div class="moz-cite-prefix">defining A=1 should be the same as
defining celldm(1)=1.889...=1/0.529177<br>
<br>
stefano<br>
<br>
On 23/06/2017 08:30, Isaiah Moses wrote:<br>
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cite="mid:CACtZ-ygRC26bSOKdKf+0p=hcFPMuv-pOWB9qAas6mF+S1QkmrQ@mail.gmail.com">
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<div>Hi Paolo,<br>
</div>
But how does one set CELL_PARAMETERS (angstrom)?<br>
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Because I observe that the output I obtain from vc-relax
is automatically set to <br>
CELL_PARAMETERS (alat= 8.11400000).<br>
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Does that has to do with the unit of celldm?<br>
<br>
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I must be missing something on theses units' usage.<br>
<br>
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I appreciate your usual prompt response,<br>
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Isaiah<br>
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<div class="gmail_extra"><br>
<div class="gmail_quote">On Fri, Jun 23, 2017 at 7:16 AM, Paolo
Giannozzi <span dir="ltr"><<a
href="mailto:p.giannozzi@gmail.com" target="_blank"
moz-do-not-send="true">p.giannozzi@gmail.com</a>></span>
wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0
.8ex;border-left:1px #ccc solid;padding-left:1ex">And, by
the way, it is a bad habit to set the lattice parameter to
the<br>
conversion factor between a.u. and A. One should use instead<br>
CELL_PARAMETERS (angstrom)<br>
to specify lattice vectors in A<br>
<br>
Paolo<br>
<div class="HOEnZb">
<div class="h5"><br>
On Fri, Jun 23, 2017 at 4:55 AM, Stefano de Gironcoli
<<a href="mailto:degironc@sissa.it"
moz-do-not-send="true">degironc@sissa.it</a>>
wrote:<br>
> The lattice parameter does not change, it is not
updated along vc-relax, the<br>
> lattice vectors do.<br>
> Using bfgs you don't need to define dt<br>
><br>
> stefano<br>
> (sent from my phone)<br>
><br>
> On 23 Jun 2017, at 01:55, Brendan Smith <<a
href="mailto:mrbsmith58@gmail.com"
moz-do-not-send="true">mrbsmith58@gmail.com</a>>
wrote:<br>
><br>
> Hello all,<br>
><br>
> I am doing a the following vc-relax calculation and
the unit cell paramters<br>
> are not changing. I have looked at other posts
which descirbes similar<br>
> problems, but it does not remedy my problem. Below
is my input.<br>
> Best,<br>
> Brendan<br>
><br>
><br>
> &CONTROL<br>
> calculation = 'vc-relax',<br>
> dt = 20.67055,<br>
> nstep = 1000,<br>
> pseudo_dir = './'<br>
> outdir = './',<br>
> prefix = 'x',<br>
> disk_io = 'low',<br>
> /<br>
><br>
> &SYSTEM<br>
> ibrav = 0,<br>
> celldm(1) = 1.89,<br>
> nat = 16,<br>
> ntyp = 3,<br>
> nspin = 1,<br>
> nbnd = 120,<br>
> ecutwfc = 70,<br>
> ecutrho = 560,<br>
> tot_charge = 0.0,<br>
> occupations = 'smearing',<br>
> smearing = 'gaussian',<br>
> degauss = 0.005,<br>
> nosym = .true.,<br>
> /<br>
><br>
> &ELECTRONS<br>
> electron_maxstep = 1000,<br>
> conv_thr = 1.D-5,<br>
> mixing_beta = 0.45,<br>
> /<br>
><br>
> &IONS<br>
> ion_dynamics = 'bfgs',<br>
> ion_temperature = 'andersen',<br>
> tempw = 300.00 ,<br>
> nraise = 1,<br>
> /<br>
><br>
> &CELL<br>
> cell_dynamics = 'bfgs',<br>
> press_conv_thr = 0.5,<br>
> cell_factor = 2.0,<br>
> cell_dofree = 'all',<br>
> /<br>
><br>
> ATOMIC_SPECIES<br>
> O 15.9994 O_pbe_v1.2.uspp.F.UPF<br>
> V 50.9415 V_pbe_v1.uspp.F.UPF<br>
> Pb 207.2 Pb.pbe-dn-rrkjus_psl.0.2.2.UPF<br>
><br>
> K_POINTS automatic<br>
> 3 3 3 0 0 0<br>
><br>
> CELL_PARAMETERS (alat)<br>
> 11.5439996719 0.0000000000
0.0000000000<br>
> 0.0000000000 3.5710000992
0.0000000000<br>
> 0.0000000000 0.0000000000
4.3829998970<br>
><br>
> ATOMIC_POSITIONS (alat)<br>
> V 6.940599 0.892750 0.475994<br>
> V 4.603400 2.678250 3.907006<br>
> V 10.375401 0.892750 0.475994<br>
> V 1.168599 2.678250 3.907006<br>
> O 4.974309 0.892750 4.370728<br>
> O 6.569691 2.678250 0.012272<br>
> O 0.797690 0.892750 4.370728<br>
> O 10.746309 2.678250 0.012272<br>
> O 6.978348 0.892750 2.058695<br>
> O 4.565652 2.678250 2.324305<br>
> O 10.337652 0.892750 2.058695<br>
> O 1.206349 2.678250 2.324305<br>
> O 8.658000 0.892750 0.003506<br>
> O 2.886000 2.678250 4.379493<br>
> Pb 8.500000 2.500000 1.500000<br>
> Pb 3.000000 1.500000 3.000000<br>
><br>
><br>
><br>
><br>
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<span class="HOEnZb"><font color="#888888">--<br>
Paolo Giannozzi, Dip. Scienze Matematiche Informatiche e
Fisiche,<br>
Univ. Udine, via delle Scienze 208, 33100 Udine, Italy<br>
Phone +39-0432-558216, fax +39-0432-558222<br>
</font></span>
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-- <br>
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<div>
<div>Isaiah Abu Moses<br>
</div>
<div>Graduate Student,<br>
</div>
Physics Department,<br>
</div>
University of Ibadan,<br>
</div>
Nigeria<br>
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