<div class="aju"><img id=":0_16-e" name=":0" src="https://ssl.gstatic.com/ui/v1/icons/mail/profile_mask2.png" class="ajn" style="background-color: #a4c2f4"></div><span class="gD">Sir, Stefano de Gironcoli</span> Thank you For your kind reply.<br>
Yes i have tested my convergence issue but unable to figure out exactly which energy cut off and k point should i select.<br>First i was tried with kpoint=gamma (0 0 0 0 0 0), for fast convergence and i obtained stress(Kbar)=0.24 at 95 Ry of ecut. The number of iteration is 8-9 in every case.<br>
<br>Convergence test at kpoint= 0 0 0 0 0 0 (gamma)<br>ecut(Ry) stress(kbar) etot(Ry)<br>23 -856.12 -22.45678789<br>28 -816.21 -22.74277097<br>33 -717.31 -22.99913807<br>
38 -640.04 -23.13068593<br>43 -538.05 -23.24446298<br>48 -388.44 -23.36265311 <br>53 -298.19 -23.41743393<br>58 -228.34 -23.44939498<br>
63 -147.46 -23.48057851<br>68 -107.24 -23.49317545<br>73 -81.19 -23.50039187<br>78 -48.03 -23.50793794<br>83 -22.26 -23.51292707<br>
88 -10.40 -23.51479400<br>93 -3.80 -23.51569322<br>94 -2.96 -23.51578788<br>95 0.24 -23.51615658<br>96 0.24 -23.51615658<br>
97 1.44 -23.51628362<br>98 1.44 -23.51628362<br><br>Second with taking kpoint in consideration again the stress was increased at fix ecut=95Ry. And if i decreased or increased the ecut from 95 Ry to 63Ry and 115Ry , the stress value increases and decreased very small respectively . <br>
Please see the below which i was mention above in wording.<br>when cosider k point...fix ecut=95<br>k mess stress(kbar) etot(Ry)<br>1*1*1 0.24 -23.51615658<br>2*2*2 -107.01 -24.24731157 <br>
3*3*3 -146.30 -24.33808965<br>4*4*4 -149.74 -24.34988328 <br>5*5*5 -149.91 -24.35200695<br>6*6*6 -149.97 -24.35245199<br>8*8*8 -149.85 -24.35256921<br>
10*10*10 -150.01 -24.35257467<br><br>when we chnage the ecut 95 to 63:::<br>8*8*8 -279.21 -24.31814193 <br><br>when we chnage the ecut= 115Ry:::<br>8*8*8 -142.60 -24.35372918<br>
<br>Please any suggestion will be appreciable.<br><br><br><br><br><div class="gmail_quote">On Fri, Feb 24, 2012 at 1:45 AM, Stefano de Gironcoli <span dir="ltr"><<a href="mailto:degironc@sissa.it">degironc@sissa.it</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><u></u>
<div bgcolor="#ffffff" text="#000000"><div class="im">
A norm conserving Nitrogen pseudo-potential is likely to require
much more that 28 Ry.<br>
have you studied the convergence of your calculated energy and
stress with respect to cutoff and k-point sampling ?<br>
<br>
Stefano de Gironcoli <br>
<br>
On 02/23/2012 07:41 PM, bramha pandey wrote:
</div><blockquote type="cite"><div><div class="h5">
<pre>Dear all QE users and developers..
I want to calculate the property of system at T=0 K and at P=0 kbar at
starting of my pw.x run.
But at the end of run, i obtained force=0 but stress p =-832.77 kbar.
I am afraid of this stress value. my input file is given below.
&CONTROL
calculation = 'scf' ,
restart_mode = 'from_scratch' ,
outdir = '.' ,
pseudo_dir = './' ,
prefix = 'aln' ,
tstress = .true. ,
tprnfor = .true. ,
/
&SYSTEM
ibrav = 2,
celldm(1) = 8.285,
nat = 2,
ntyp = 2,
ecutwfc = 28 ,
/
&ELECTRONS
conv_thr = 1.0d-8 ,
mixing_beta = 0.7 ,
/
ATOMIC_SPECIES
Al 26.98000 Al.pz-vbc.UPF
N 14.01000 N.pz-vbc.UPF
ATOMIC_POSITIONS alat
Al 0.000000000 0.000000000 0.000000000
N 0.250000000 0.250000000 0.250000000
K_POINTS automatic
4 4 4 0 0 0
Any type of help is highly appreciated.
</pre>
</div></div><pre><fieldset></fieldset>
_______________________________________________
Pw_forum mailing list
<a href="mailto:Pw_forum@pwscf.org" target="_blank">Pw_forum@pwscf.org</a>
<a href="http://www.democritos.it/mailman/listinfo/pw_forum" target="_blank">http://www.democritos.it/mailman/listinfo/pw_forum</a>
</pre>
</blockquote>
<br>
</div>
<br>_______________________________________________<br>
Pw_forum mailing list<br>
<a href="mailto:Pw_forum@pwscf.org">Pw_forum@pwscf.org</a><br>
<a href="http://www.democritos.it/mailman/listinfo/pw_forum" target="_blank">http://www.democritos.it/mailman/listinfo/pw_forum</a><br>
<br></blockquote></div><br><br clear="all"><br>-- <br>Thanks and Regards<br>Bramha Prasad Pandey<br>GLA University, Mathura.<br>INDIA.<br><br>