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<div class="moz-cite-prefix">On 11/08/2013 08:31 AM, Suresh A wrote:<br>
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<div>Dear Everybody,<br>
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Thank You for your reply.<br>
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Dear Sava,<br>
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In your reply you have quoted that " you
need not worry about symmetry conservation" is that means
did i use any symmetry conservation like card in my input
file?<br>
<br>
<br>
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Dear Giuseppe,<br>
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First i did vc-relax with ecutwfc=50 and
ecutrho=200. for that input file that input file iget output as
follows.<br>
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<div> entering subroutine stress ...<br>
<br>
total stress (Ry/bohr**3)
(kbar) P= -0.08<br>
-0.00000057 -0.00000025 0.00000000 -0.08
-0.04 0.00<br>
-0.00000025 -0.00000057 0.00000000 -0.04
-0.08 0.00<br>
0.00000000 0.00000000 -0.00000047 0.00
0.00 -0.07<br>
<br>
<br>
bfgs converged in 7 scf cycles and 5 bfgs steps<br>
(criteria: energy < 0.10E-04, force < 0.10E-03,
cell < 0.20E+01)<br>
<br>
End of BFGS Geometry Optimization<br>
<br>
Final enthalpy = -142.8393726978 Ry<br>
Begin final coordinates<br>
new unit-cell volume = 365.14428 a.u.^3 (
54.10880 Ang^3 )<br>
<br>
CELL_PARAMETERS (alat= 8.68089163)<br>
0.951086548 0.000003754 0.000000000<br>
0.000003754 0.951086548 0.000000000<br>
0.000000000 0.000000000 0.617065718<br>
<br>
<br>
entering subroutine stress ...<br>
<br>
total stress (Ry/bohr**3)
(kbar) P= -233.71<br>
-0.00161914 -0.00000028 0.00000000 -238.18
-0.04 0.00<br>
-0.00000028 -0.00161914 0.00000000 -0.04
-238.18 0.00<br>
0.00000000 0.00000000 -0.00152791 0.00
0.00 -224.76<br>
<br>
<br>
Writing output data file pwscf.save<br>
<br>
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<div>there was a very large difference between last
converged structures kbar values so i suddenly change
energy cuttoffs values to 200/800. Futhermore i create
this inputfile with the help of pwgui. Pwgui automatically
inserted exxdiv_treatment card which i didn't notice in my
calculation. I got some clues on my calculation. I will
reply soon to your answer.<br>
<br>
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<div>Dear Emine, <br>
</div>
<div> I took pseudopotential as it is from
quantum espresso website. i didn't check on it whether it
is hard pseudopotential or soft one. the i choose higher
cutoff because to reduce kbar difference as i shown above.
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<div>After i check my calculation i will reply to you.<br>
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<div> Thank you all once again<br
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With Regards,<br>
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<div style="text-align:right">A.Suresh,<br>
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<div style="text-align:right">Project
Fellow,<br>
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<div style="text-align:right">Madurai Kamaraj
University,<br>
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<div style="text-align:right">Madurai.<br>
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<br>
Symmetry with orthogonal axes is automatically conserved <br>
(primitive-cell) in vc-relax. Additionaly "cell-factor" variable
should also <br>
take your attention. Take its value more than its defaut <br>
(such as between 1.5-2.0). According to the output tiO2 <br>
cell did not contract so much, but you can test whether or not the
<br>
expansion of reciprocal space is enough to reinterpolate (fairly)
the tables. <br>
<br>
Note : In your output it seems that symmetry (tetragonal) is
breaked (slightly). <br>
I don't know why it's occured but make sure that all
pseudopotential <br>
and cutoff related issues solved before attempt to
solve symmetry <br>
related ones.<br>
<br>
Savaş AĞDUK<br>
Research Assistant<br>
Karabuk University<br>
Physics Department<br>
<br>
<br>
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