Dear Wang,<div> The 'relax' process optimizes the structure within given geometric constraint. It does'nt care for stress. It minimizes force only in the given constraint. If you want to minimize the stress also you have to do 'vc-relax' calculation, It will give you what you want.<br>
<div><br><div class="gmail_quote">On Mon, Sep 20, 2010 at 11:37 AM, Wang Di <span dir="ltr"><<a href="mailto:didi5158@gmail.com">didi5158@gmail.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex;">
Dear all<br><br>I perform the relax calculate to the crystal structure. After 11 step bfgs, the total force and total scf correction had reach to the criterion, however, the total stress was so big P=-3443.87. I have no idea about deal with the case, could anyone give some advices? Thanks in advance.<br>
<br>the input file<br>: &CONTROL<br> calculation = 'scf' ,<br> restart_mode = 'from_scratch' ,<br> wf_collect = .true. ,<br> outdir = '/lustre/AIOFM/gxgu/workLCAF/5/temp/' ,<br>
wfcdir = '/lustre/AIOFM/gxgu/workLCAF/5/wftemp/' ,<br> pseudo_dir = '/home/AIOFM/gxgu/work/NCPP/' ,<br> prefix = 'LCAF' ,<br> etot_conv_thr = 1.0D-7 ,<br>
forc_conv_thr = 1.0D-6 ,<br> nstep = 100 ,<br> tstress = .true. ,<br> tprnfor = .true. ,<br> dipfield = .true. ,<br> /<br> &SYSTEM<br>
ibrav = 4,<br> celldm(1) = 9.42432151,<br> celldm(3) = 1.94804220,<br> nat = 18,<br> ntyp = 4,<br> ecutwfc = 30 ,<br>
ecutrho = 120 ,<br> nosym = .false. ,<br> /<br> &ELECTRONS<br> electron_maxstep = 100,<br> conv_thr = 1.0D-10 ,<br> /<br>ATOMIC_SPECIES<br> Li 6.94100 03-Li.LDA.fhi.UPF <br>
Al 26.98154 13-Al.LDA.fhi.UPF <br> Ca 40.07800 20-Ca.LDA.fhi.UPF <br> F 18.99840 09-F.LDA.fhi.UPF <br>ATOMIC_POSITIONS crystal <br> Li 0.333333333 0.666666667 0.250000000 <br> Li -0.333333333 -0.666666667 -0.250000000 <br>
F 0.389997 0.045970 0.148326 <br> F -0.045970 0.344027 0.148326 <br> F -0.344027 -0.389997 0.148326 <br> F -0.045970 -0.389997 0.351674 <br>
F -0.344027 0.045970 0.351674 <br> F 0.389997 0.344027 0.351674 <br> F -0.389997 -0.045970 -0.148326 <br> F 0.045970 -0.344027 -0.148326 <br>
F 0.344027 0.389997 -0.148326 <br> F 0.045970 0.389997 0.648326 <br> F 0.344027 -0.045970 0.648326 <br> F -0.389997 -0.344027 0.648326 <br>
Al 0.666666667 0.333333333 0.250000000 <br> Al -0.666666667 -0.333333333 -0.250000000 <br> Ca 0.000000000 0.000000000 0.000000000 <br> Ca 0.000000000 0.000000000 0.500000000 <br>
K_POINTS automatic <br> 16 16 16 0 0 0 <br><br>best regart<br><br>Wang Di<br clear="all"><br>-- <br>-----------------------------------------------------------------<br><font color="#888888"><i style="font-family:comic sans ms,sans-serif">Wang Di</i><i style="font-family:comic sans ms,sans-serif"><br>
The Crystal Lab,</i><br><i style="font-family:comic sans ms,sans-serif"><span style="font-size:10pt" lang="EN-US">AnHui Institute of Optics and Fine Mechanics, </span></i><i style="font-family:comic sans ms,sans-serif"></i><br>
<i style="font-family:comic sans ms,sans-serif"><span style="font-size:10pt" lang="EN-US">Chinese Academy of Sciences,</span></i><i style="font-family:comic sans ms,sans-serif"><span style="font-size:10pt" lang="EN-US"><br>
No350. , Shushanhu Road, Hefei,
230031, China</span><span style="font-size:10pt" lang="EN-US"></span></i><i style="font-family:comic sans ms,sans-serif"><span style="font-size:10pt" lang="EN-US">,<br>E-mail: didi5158 @gmail.ocm</span></i><i style="font-family:comic sans ms,sans-serif">
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<br></blockquote></div><br><br clear="all"><br>-- <br>Regards,<br>MOHNISH,<br>-----------------------------------------------------------------<br>Mohnish Pandey<br>Y6927262,5th Year dual degree student,<br>Department of Chemical Engineering,<br>
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