<div><br>Dear Eyvaz :</div>
<div> </div>
<div>I just relaxed Anatase TiO2 with <strong>ibrav= 7 , </strong></div>
<div>then output gave that Only 8 symmetry Operations are found. </div>
<div>According to your mail, this structure should have 16 Symmetry Operations, so </div>
<div>how can i obtain correct symmetry operations ? </div>
<div> </div>
<div>Input file is below , thank you in advance !</div>
<div> </div>
<div>
<p><strong>&CONTROL<br> title = 'TiO2' ,<br> calculation = 'relax',<br> verbosity = 'default',<br> tprnfor = .true.,<br> outdir = '/home/haiping/tmp/',<br> prefix = 'tio2-1',
<br> disk_io = 'default',<br> nstep = 200,<br> pseudo_dir = '/home/haiping/espresso/pseudo/',<br>/</strong></p>
<p><strong>&SYSTEM<br> ibrav= 7,<br> celldm(1)=7.1356,celldm(3)=2.51218,<br> nat = 6 ,<br> ntyp = 2 ,<br> nbnd = 30 ,<br> ecutwfc = 30.0000000000
,<br> occupations = 'fixed' ,<br></strong></p>
<p><strong>&ELECTRONS<br> electron_maxstep = 100,<br> conv_thr = 1.0e-09,<br> mixing_mode = 'plain' ,<br> startingpot = 'atomic' ,<br> startingwfc = 'atomic' ,<br> mixing_beta = 0.300000000
,<br> mixing_ndim = 8,<br> diagonalization = 'david_overlap' ,<br> diago_david_ndim = 8,<br>/</strong></p>
<p><strong>&IONS<br> ion_dynamics = 'bfgs',<br> pot_extrapolation = 'first_order',<br> wfc_extrapolation = 'first_order',</strong></p>
<p><strong>/</strong></p>
<p><strong>O 15.999 O.pw91-van_ak.UPF<br>Ti 47.867 Ti.pw91-nsp-van.UPF<br>ATOMIC_POSITIONS angstrom<br>Ti 0.000000000 0.000000000 0.000000000<br>Ti 0.000000000 1.888000000 2.371500000<br>O 0.000000000
0.000000000 -1.983097630<br>O 0.000000000 0.000000000 1.983097630<br>O 0.000000000 1.888000000 0.387796645<br>O 0.000000000 1.888000000 4.355203355<br>K_POINTS automatic<br>6 6 7 0 0 0
<br></strong></p></div>
<div><strong><br> </strong></div>
<div><span class="gmail_quote">On 8/20/06, <b class="gmail_sendername">Eyvaz Isaev</b> <<a href="mailto:eyvaz_isaev@yahoo.com">eyvaz_isaev@yahoo.com</a>> wrote:</span>
<blockquote class="gmail_quote" style="PADDING-LEFT: 1ex; MARGIN: 0px 0px 0px 0.8ex; BORDER-LEFT: #ccc 1px solid">OK, let me hint more.<br><br>Anatase has a Pearson symbol tI12 or space group<br>I4_1/amd. So, ibrav should be 7, but you have chosen a
<br>monoclinic lattice, i.e. ibrav=14. The space group has<br>16 symmetry elements, but your choice after correcting<br>ecutrho gives only 4 symmetry elements .<br><br>Imagine FCC lattice and its conventional basis<br>vectors now. According to you now we have to put
<br>ibrav=4 or 5. But ibrav=2 for FCC lattice.<br><br>In addition, I also checked your input file via<br>XCrysDen before I replied previously. Yes, there is no<br>problem with it, but a figure does not look like<br>anatase though you used nonzero ibrav. XcrysDen
<br>usually replicates atomic positions if ibrav.neq.0.<br>For example, if you put ibrav=0 for FCC cell and<br>specify conventional CELL_PARAMETERS you will find a<br>rhombohedron, but using ibrav=2 and default basis
<br>vectors you find a cubic cell.<br><br>Bests,<br>Eyvaz.<br><br><br>--- lan haiping <<a href="mailto:lanhaiping@gmail.com">lanhaiping@gmail.com</a>> wrote:<br><br>> Dear Eyvaz,<br>> Thank you.<br>> I checked the strcuture again using XCRYSDEN,
<br>> and found no problems related to the lattices.<br>><br>> Regards,<br>><br>> Hai-Ping<br>><br>><br>><br>> On 8/20/06, Eyvaz Isaev <<a href="mailto:eyvaz_isaev@yahoo.com">eyvaz_isaev@yahoo.com
</a>><br>> wrote:<br>> ><br>> > Hi,<br>> ><br>> > It seems your lattice choice is not correct.<br>> Please<br>> > have a look at<br>> > <a href="http://cst-www.nrl.navy.mil/lattice/struk/c5.html">
http://cst-www.nrl.navy.mil/lattice/struk/c5.html</a><br>> ><br>> > Bests,<br>> > Eyvaz.<br>> ><br>> > --- lan haiping <<a href="mailto:lanhaiping@gmail.com">lanhaiping@gmail.com</a>> wrote:
<br>> ><br>> > > Dear All,<br>> > > I also have calculated gamma phonon frequencies<br>> of<br>> > > anatase TiO2 .<br>> > > I run ph.x caculation after relaxing the<br>> structure,
<br>> > > but 9 of 18 frequencies<br>> > > are minus.<br>> > ><br>> > > Would you please give me some hints and help?<br>> > ><br>> > > input settings are below, thank you in advance !
<br>> > ><br>> > > *phonons of TiO2 at Gamma<br>> > > &inputph<br>> > > tr2_ph=1.0d-14,<br>> > > recover=.true.,<br>> > > epsil=.true.,<br>> > > prefix='tio2',
<br>> > > fildyn='TiO2-gamma.dyn',<br>> > > outdir='/home/haiping/tmp/'<br>> > > /<br>> > > 0.0 0.0 0.0*<br>> > > **<br>> > > *Relaxing calculation input :*<br>> > > *&CONTROL
<br>> > > title = 'TiO2' ,<br>> > > calculation = 'relax',<br>> > > verbosity = 'default',<br>> > > tprnfor = .true.,<br>> > > outdir = '/home/haiping/tmp/',
<br>> > > prefix = 'tio2',<br>> > > disk_io = 'default',<br>> > > nstep = 200,<br>> > > pseudo_dir =<br>> > > '/home/haiping/espresso/pseudo/',
<br>> > > /<br>> > > &SYSTEM<br>> > > ibrav= 14,<br>> > ><br>> > > celldm(1)=10.2856,celldm(2)=1.0,celldm(3)=1.0,<br>> > ><br>> > > celldm(4)=-
0.759357,celldm(5)=-0.759357,<br>> > > celldm(6)=0.518714<br>> > > nat = 6 ,<br>> > > ntyp = 2 ,<br>> > > nbnd = 30 ,<br>> > > ecutwfc =
30.0000000000,<br>> > > ecutrho = 160.000,<br>> > > occupations = 'fixed' ,<br>> > > /<br>> > ><br>> > ><br>> > > &ELECTRONS<br>> > > electron_maxstep = 100,
<br>> > > conv_thr = 1.0e-07,<br>> > > mixing_mode = 'plain' ,<br>> > > startingpot = 'atomic' ,<br>> > > startingwfc = 'atomic' ,<br>> > > mixing_beta =
0.300000000,<br>> > > mixing_ndim = 8,<br>> > > diagonalization = 'david_overlap' ,<br>> > > diago_david_ndim = 8,<br>> > > /<br>> > ><br>> > > &IONS<br>
> > > ion_dynamics = 'bfgs',<br>> > > pot_extrapolation = 'first_order',<br>> > > wfc_extrapolation = 'first_order',<br>> > ><br>> > > /<br>
> > ><br>> > > ATOMIC_SPECIES<br>> > > O 15.999 O.pw91-van_ak.UPF<br>> > > Ti 47.867 Ti.pw91-nsp-van.UPF<br>> > > ATOMIC_POSITIONS crystal<br>> > > Ti 0.00000 0.00000
0.00000<br>> > > Ti 0.75000 0.25000 0.50000<br>> > > O 0.20800 0.20800 -0.00000<br>> > > O 0.95800 0.45800 0.50000<br>> > > O 0.54200 0.04200 0.50000<br>
> > > O 0.79200 0.79200 -0.00000<br>> > > K_POINTS automatic<br>> > > 6 6 7 0 0 0<br>> > ><br>> > > *<br>> > ><br>> > ><br>> > > On 8/19/06, Ezad Shojaee
<br>> <<a href="mailto:ezadshojaee@hotmail.com">ezadshojaee@hotmail.com</a>><br>> > > wrote:<br>> > > ><br>> > > > hi<br>> > > > i am trying to calculate phonon frequencies at
<br>> > > gamma point of<br>> > > > TiO2(anatase)<br>> > > > and i have relaxed the structure enough (i<br>> think<br>> > > )but performing PH.Xafter<br>> > > > scf, 2of 18 frequencies are minus!
<br>> > > > i want to know that what technical problem do<br>> i<br>> > > have? does anyone<br>> > > > calculate<br>> > > > these beore?<br>> > > > any suggestion will be appreciated
<br>> > > ><br>> > > ><br>> > ><br>> ><br><br>--- lan haiping <<a href="mailto:lanhaiping@gmail.com">lanhaiping@gmail.com</a>> wrote:<br><br>> Dear Eyvaz,<br>> Thank you.
<br>> I checked the strcuture again using XCRYSDEN,<br>> and found no problems related to the lattices.<br>><br>> Regards,<br>><br>> Hai-Ping<br>><br>><br>><br>> On 8/20/06, Eyvaz Isaev <
<a href="mailto:eyvaz_isaev@yahoo.com">eyvaz_isaev@yahoo.com</a>><br>> wrote:<br>> ><br>> > Hi,<br>> ><br>> > It seems your lattice choice is not correct.<br>> Please<br>> > have a look at
<br>> > <a href="http://cst-www.nrl.navy.mil/lattice/struk/c5.html">http://cst-www.nrl.navy.mil/lattice/struk/c5.html</a><br>> ><br>> > Bests,<br>> > Eyvaz.<br>> ><br>> > --- lan haiping <
<a href="mailto:lanhaiping@gmail.com">lanhaiping@gmail.com</a>> wrote:<br>> ><br>> > > Dear All,<br>> > > I also have calculated gamma phonon frequencies<br>> of<br>> > > anatase TiO2 .
<br>> > > I run ph.x caculation after relaxing the<br>> structure,<br>> > > but 9 of 18 frequencies<br>> > > are minus.<br>> > ><br>> > > Would you please give me some hints and help?
<br>> > ><br>> > > input settings are below, thank you in advance !<br>> > ><br>> > > *phonons of TiO2 at Gamma<br>> > > &inputph<br>> > > tr2_ph=1.0d-14,<br>> > > recover=.true.,
<br>> > > epsil=.true.,<br>> > > prefix='tio2',<br>> > > fildyn='TiO2-gamma.dyn',<br>> > > outdir='/home/haiping/tmp/'<br>> > > /<br>> > > 0.0 0.0 0.0*<br>> > > **
<br>> > > *Relaxing calculation input :*<br>> > > *&CONTROL<br>> > > title = 'TiO2' ,<br>> > > calculation = 'relax',<br>> > > verbosity = 'default',
<br>> > > tprnfor = .true.,<br>> > > outdir = '/home/haiping/tmp/',<br>> > > prefix = 'tio2',<br>> > > disk_io = 'default',<br>> > > nstep = 200,
<br>> > > pseudo_dir =<br>> > > '/home/haiping/espresso/pseudo/',<br>> > > /<br>> > > &SYSTEM<br>> > > ibrav= 14,<br>> > ><br>> > > celldm(1)=
10.2856,celldm(2)=1.0,celldm(3)=1.0,<br>> > ><br>> > > celldm(4)=-0.759357,celldm(5)=-0.759357,<br>> > > celldm(6)=0.518714<br>> > > nat = 6 ,<br>> > > ntyp = 2 ,
<br>> > > nbnd = 30 ,<br>> > > ecutwfc = 30.0000000000,<br>> > > ecutrho = 160.000,<br>> > > occupations = 'fixed' ,<br>> > > /<br>> > >
<br>> > ><br>> > > &ELECTRONS<br>> > > electron_maxstep = 100,<br>> > > conv_thr = 1.0e-07,<br>> > > mixing_mode = 'plain' ,<br>> > > startingpot = 'atomic' ,
<br>> > > startingwfc = 'atomic' ,<br>> > > mixing_beta = 0.300000000,<br>> > > mixing_ndim = 8,<br>> > > diagonalization = 'david_overlap' ,<br>> > > diago_david_ndim = 8,
<br>> > > /<br>> > ><br>> > > &IONS<br>> > > ion_dynamics = 'bfgs',<br>> > > pot_extrapolation = 'first_order',<br>> > > wfc_extrapolation = 'first_order',
<br>> > ><br>> > > /<br>> > ><br>> > > ATOMIC_SPECIES<br>> > > O 15.999 O.pw91-van_ak.UPF<br>> > > Ti 47.867 Ti.pw91-nsp-van.UPF<br>> > > ATOMIC_POSITIONS crystal
<br>> > > Ti 0.00000 0.00000 0.00000<br>> > > Ti 0.75000 0.25000 0.50000<br>> > > O 0.20800 0.20800 -0.00000<br>> > > O 0.95800 0.45800 0.50000<br>> > > O
0.54200 0.04200 0.50000<br>> > > O 0.79200 0.79200 -0.00000<br>> > > K_POINTS automatic<br>> > > 6 6 7 0 0 0<br>> > ><br>> > > *<br>> > ><br>> > >
<br>> > > On 8/19/06, Ezad Shojaee<br>> <<a href="mailto:ezadshojaee@hotmail.com">ezadshojaee@hotmail.com</a>><br>> > > wrote:<br>> > > ><br>> > > > hi<br>> > > > i am trying to calculate phonon frequencies at
<br>> > > gamma point of<br>> > > > TiO2(anatase)<br>> > > > and i have relaxed the structure enough (i<br>> think<br>> > > )but performing PH.Xafter<br>> > > > scf, 2of 18 frequencies are minus!
<br>> > > > i want to know that what technical problem do<br>> i<br>> > > have? does anyone<br>> > > > calculate<br>> > > > these beore?<br>> > > > any suggestion will be appreciated
<br>> > > ><br>> > > ><br>> > ><br>> ><br>><br>_________________________________________________________________<br>> > > > Express yourself instantly with MSN Messenger!
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