<html><head><meta http-equiv="Content-Type" content="text/html; charset=utf-8"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; line-break: after-white-space;" class="">not “unphysical” just inaccurate … SB<div class=""><br class=""><div><br class=""><blockquote type="cite" class=""><div class="">On 5 Apr 2018, at 19:39, Jie Peng <<a href="mailto:jiepeng@umd.edu" class="">jiepeng@umd.edu</a>> wrote:</div><br class="Apple-interchange-newline"><div class=""><div dir="ltr" class="">Stefano:<div class=""><br class=""></div><div class="">I think that is right on the spot! Let me do a calculation using Gamma point only in pwscf and then compare again.</div><div class=""><br class=""></div><div class="">So for cp.x, in order to get an accurate lattice structure, one would have to use a n*n*n supercell instead of a unit cell since it can only process real wavefunctions that are located at Gamma point only. Computations done on a single unit cell using cp.x code, therefore usually produces results that are unphysical. Is this the correct way to interpretate?</div><div class=""><br class=""></div><div class="">Thank you very much!</div><div class=""><br class=""></div><div class="">Best</div><div class="">Jie</div></div><div class="gmail_extra"><br class=""><div class="gmail_quote">On Thu, Apr 5, 2018 at 2:22 AM, Stefano de Gironcoli <span dir="ltr" class=""><<a href="mailto:degironc@sissa.it" target="_blank" class="">degironc@sissa.it</a>></span> wrote:<br class=""><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
<div bgcolor="#FFFFFF" text="#000000" class=""><p class=""><tt class="">Dear </tt>Jie Peng,</p><p class=""> the cp.x code assumes gamma point sampling and does not
process your k-point definition card, while pw.x is using, a
rather dense, grid of points in the BZ.</p><p class=""> I think this is the most relevant difference in your two
inputs.</p><p class=""> To see if this is the case you can repeat the pw.x calculation
with <br class="">
</p><p class="">K_POINT Gamma<br class="">
</p><p class=""> Is the 10 8 8 grid really necessary ? is the system metallic ?
<br class="">
</p><p class=""> if not I guess a smaller grid (like 6 4 4 or less) could be
sufficient and then you could use the cp.x code with a
corresponding supercell if you wish so.<br class="">
</p><p class="">stefano<br class="">
</p><div class=""><div class="h5">
<br class="">
<div class="m_4773530265834723698moz-cite-prefix">On 05/04/2018 04:16, Jie Peng wrote:<br class="">
</div>
</div></div><blockquote type="cite" class=""><div class=""><div class="h5">
<div dir="ltr" class="">Dear all Quantum Espresso users:
<div class=""><br class="">
</div>
<div class="">I have used pw.x and cp.x code to compute equilibrium
lattice structure of 1T-HfS2 (Halfnium Disulfide)
respectively, and I find that they give very different
results.</div>
<div class=""><br class="">
</div>
<div class=""><b class="">For pwscf simulation, the input file are given below.</b></div>
<div class="">
<div class=""><i class="">&control</i></div>
<div class=""><i class=""> calculation='vc-relax',</i></div>
<div class=""><i class="">! restart_mode='from_scratch',</i></div>
<div class=""><i class=""> tstress = .true.</i></div>
<div class=""><i class=""> tprnfor = .true.</i></div>
<div class=""><i class=""> </i></div>
<div class=""><i class=""> wf_collect=.true.</i></div>
<div class=""><i class=""> etot_conv_thr=1e-6</i></div>
<div class=""><i class=""> forc_conv_thr=1e-5</i></div>
<div class=""><i class=""> prefix='Hf',</i></div>
<div class=""><i class=""> pseudo_dir='/potential'</i></div>
<div class=""><i class=""> outdir='./tmp/',</i></div>
<div class=""><i class=""> /</i></div>
<div class=""><i class=""> &system</i></div>
<div class=""><i class=""> ibrav= 4,</i></div>
<div class=""><i class=""> a=3.6529</i></div>
<div class=""><i class=""> c=5.6544</i></div>
<div class=""><i class=""> nat= 3, ntyp= 2,</i></div>
<div class=""><i class=""> ecutwfc =50</i></div>
<div class=""><i class=""> vdw_corr='DFT-D',</i></div>
<div class=""><i class=""> ! lspinorb=.true.</i></div>
<div class=""><i class=""> ! noncolin=.true.</i></div>
<div class=""><i class=""> ! ecutrho=300</i></div>
<div class=""><i class=""> ! nbnd=14</i></div>
<div class=""><i class="">! occupations='smearing'</i></div>
<div class=""><i class="">! smearing='gaussian'</i></div>
<div class=""><i class="">! degauss=0.01</i></div>
<div class=""><i class=""> ! nspin=2</i></div>
<div class=""><i class=""> ! starting_magnetization(1)=0.1</i></div>
<div class=""><i class="">/</i></div>
<div class=""><i class=""> &electrons</i></div>
<div class=""><i class=""> conv_thr=1e-12</i></div>
<div class=""><i class=""> mixing_beta = 0.7</i></div>
<div class=""><i class="">/</i></div>
<div class=""><i class=""> &ions</i></div>
<div class=""><i class=""> ion_dynamics = 'bfgs'</i></div>
<div class=""><i class=""> /</i></div>
<div class=""><i class=""> &cell</i></div>
<div class=""><i class=""> cell_dynamics = 'bfgs'</i></div>
<div class=""><i class=""> </i></div>
<div class=""><i class="">/</i></div>
<div class=""><i class="">ATOMIC_SPECIES</i></div>
<div class=""><i class=""> Hf 95.94 Hf.pbe-mt_fhi.UPF</i></div>
<div class=""><i class=""> S 32.065 S.pbe-mt_fhi.UPF</i></div>
<div class=""><i class="">ATOMIC_POSITIONS (crystal)</i></div>
<div class=""><i class="">Hf -0.000000000 -0.000000000 -0.000000000</i></div>
<div class=""><i class="">S 0.666666667 0.333333333 0.257234636</i></div>
<div class=""><i class="">S 0.333333333 0.666666667 -0.257234636</i></div>
<div class=""><i class=""> K_POINTS automatic</i></div>
<div class=""><i class="">10 8 8 0 0 0</i></div>
<div class=""><br class="">
</div>
<div class="">The relaxed lattice structure is the one included in this
input file (I first did the full relaxation after which I
copied the resulting relaxed lattice structure into this
input file, then modified this file to compute electronic
structure and phonons). The forces acting on atoms are small
and I believe this should be the equilibrium structure of
1T-HfS2.</div>
<div class=""><br class="">
</div>
<div class="">
<div class=""><i class=""> Forces acting on atoms (Ry/au):</i></div>
<div class=""><i class=""><br class="">
</i></div>
<div class=""><i class=""> atom 1 type 1 force = 0.00000000
0.00000000 0.00000000</i></div>
<div class=""><i class=""> atom 2 type 2 force = 0.00000000
0.00000000 -0.00001404</i></div>
<div class=""><i class=""> atom 3 type 2 force = -0.00000000
0.00000000 0.00001404</i></div>
<div class=""><i class=""><br class="">
</i></div>
<div class=""><i class=""> Total force = 0.000020 Total SCF
correction = 0.000001</i></div>
<div class=""><i class=""><br class="">
</i></div>
<div class=""><i class=""><br class="">
</i></div>
<div class=""><i class=""> entering subroutine stress ...</i></div>
<div class=""><i class=""><br class="">
</i></div>
<div class=""><i class=""> total stress (Ry/bohr**3)
(kbar) P= -0.16</i></div>
<div class=""><i class=""> -0.00000129 -0.00000000 0.00000000
-0.19 -0.00 0.00</i></div>
<div class=""><i class=""> -0.00000000 -0.00000129 0.00000000
-0.00 -0.19 0.00</i></div>
<div class=""><i class=""> 0.00000000 0.00000000 -0.00000078
0.00 0.00 -0.12</i></div>
</div>
<div class=""><i class=""><br class="">
</i></div>
<div class=""><b class="">For cp.x, </b>I carefully follow the steps required
to carry out a CP simulations: Relax electronic structure to
ground state -> Relax the ion positions -> relax the
cells. The input files are attached below.</div>
<div class=""><br class="">
</div>
<div class=""><b class="">Electronic relaxation</b></div>
<div class="">
<div class=""><i class="">&control</i></div>
<div class=""><i class=""> calculation='cp',</i></div>
<div class=""><i class=""> title='Halfnium disulfide'</i></div>
<div class=""><i class=""> restart_mode='from_scratch',</i></div>
<div class=""><i class=""> ndr=50,</i></div>
<div class=""><i class=""> ndw=50,</i></div>
<div class=""><i class=""> nstep=10000,</i></div>
<div class=""><i class=""> iprint=100</i></div>
<div class=""><i class=""> isave=100,</i></div>
<div class=""><i class=""> tstress = .true.</i></div>
<div class=""><i class=""> tprnfor = .true.</i></div>
<div class=""><i class=""> dt=10,</i></div>
<div class=""><i class=""> wf_collect=.true.</i></div>
<div class=""><i class=""> etot_conv_thr=1e-6</i></div>
<div class=""><i class=""> forc_conv_thr=1e-3</i></div>
<div class=""><i class=""> ekin_conv_thr=1e-5</i></div>
<div class=""><i class=""> prefix='HfS2',</i></div>
<div class=""><i class=""> pseudo_dir='/home/jpeng/HfS2/<wbr class="">potential'</i></div>
<div class=""><i class=""> outdir='./tmp/',</i></div>
<div class=""><i class=""> /</i></div>
<div class=""><i class=""> &system</i></div>
<div class=""><i class=""> ibrav= 4,</i></div>
<div class=""><i class=""> a=3.6529</i></div>
<div class=""><i class=""> c=5.6544</i></div>
<div class=""><i class=""> nat= 3, ntyp= 2,</i></div>
<div class=""><i class=""> ecutwfc =50</i></div>
<div class=""><i class=""> vdw_corr='DFT-D',</i></div>
<div class=""><i class=""> ! lspinorb=.true.</i></div>
<div class=""><i class=""> ! noncolin=.true.</i></div>
<div class=""><i class=""> ! ecutrho=300</i></div>
<div class=""><i class=""> ! nbnd=14</i></div>
<div class=""><i class="">! occupations='smearing'</i></div>
<div class=""><i class="">! smearing='gaussian'</i></div>
<div class=""><i class="">! degauss=0.01</i></div>
<div class=""><i class=""> ! nspin=2</i></div>
<div class=""><i class=""> ! starting_magnetization(1)=0.1</i></div>
<div class=""><i class="">! Hf 95.94 Hf.pbe-mt_fhi.UPF</i></div>
<div class=""><i class="">! S 32.065 S.pbe-mt_fhi.UPF</i></div>
<div class=""><i class="">/</i></div>
<div class=""><i class=""> &electrons</i></div>
<div class=""><i class=""> electron_dynamics='damp'</i></div>
<div class=""><i class="">! electron_velocities='zero'</i></div>
<div class=""><i class=""> emass=400</i></div>
<div class=""><i class=""> emass_cutoff=1</i></div>
<div class=""><i class=""> electron_damping=0.1</i></div>
<div class=""><i class="">/</i></div>
<div class=""><i class=""> &ions</i></div>
<div class=""><i class=""> ion_dynamics = 'none'</i></div>
<div class=""><i class=""> /</i></div>
<div class=""><i class=""> &cell</i></div>
<div class=""><i class=""> cell_dynamics = 'none'</i></div>
<div class=""><i class=""> </i></div>
<div class=""><i class="">/</i></div>
<div class=""><i class="">ATOMIC_SPECIES</i></div>
<div class=""><i class=""> Hf 95.94 Hf.pbe-mt_fhi.UPF</i></div>
<div class=""><i class=""> S 32.065 S.pbe-mt_fhi.UPF</i></div>
<div class=""><i class="">ATOMIC_POSITIONS (crystal)</i></div>
<div class=""><i class="">Hf -0.000000000 -0.000000000 -0.000000000</i></div>
<div class=""><i class="">S 0.666666667 0.333333333 0.257234636</i></div>
<div class=""><i class="">S 0.333333333 0.666666667 -0.257234636</i></div>
<div class=""><i class=""> K_POINTS automatic</i></div>
<div class=""><i class="">10 8 8 0 0 0</i></div>
<div style="font-weight:bold" class=""><br class="">
</div>
</div>
<div style="font-weight:bold" class="">Ion relaxation</div>
<div class="">
<div class=""><i class="">&control</i></div>
<div class=""><i class=""> calculation='cp',</i></div>
<div class=""><i class=""> title='Halfnium disulfide'</i></div>
<div class=""><i class=""> restart_mode='restart',</i></div>
<div class=""><i class=""> ndr=50,</i></div>
<div class=""><i class=""> ndw=51,</i></div>
<div class=""><i class=""> nstep=50000,</i></div>
<div class=""><i class=""> iprint=100</i></div>
<div class=""><i class=""> isave=100,</i></div>
<div class=""><i class=""> tstress = .true.</i></div>
<div class=""><i class=""> tprnfor = .true.</i></div>
<div class=""><i class=""> dt=10,</i></div>
<div class=""><i class=""> wf_collect=.true.</i></div>
<div class=""><i class=""> etot_conv_thr=1e-6</i></div>
<div class=""><i class=""> forc_conv_thr=1e-3</i></div>
<div class=""><i class=""> ekin_conv_thr=1e-5</i></div>
<div class=""><i class=""> prefix='HfS2',</i></div>
<div class=""><i class=""> pseudo_dir='/home/jpeng/HfS2/<wbr class="">potential'</i></div>
<div class=""><i class=""> outdir='./tmp/',</i></div>
<div class=""><i class=""> /</i></div>
<div class=""><i class=""> &system</i></div>
<div class=""><i class=""> ibrav= 4,</i></div>
<div class=""><i class=""> a=3.6529</i></div>
<div class=""><i class=""> c=5.6544</i></div>
<div class=""><i class=""> nat= 3, ntyp= 2,</i></div>
<div class=""><i class=""> ecutwfc =50</i></div>
<div class=""><i class=""> vdw_corr='DFT-D',</i></div>
<div class=""><i class=""> ! lspinorb=.true.</i></div>
<div class=""><i class=""> ! noncolin=.true.</i></div>
<div class=""><i class=""> ! ecutrho=300</i></div>
<div class=""><i class=""> ! nbnd=14</i></div>
<div class=""><i class="">! occupations='smearing'</i></div>
<div class=""><i class="">! smearing='gaussian'</i></div>
<div class=""><i class="">! degauss=0.01</i></div>
<div class=""><i class=""> ! nspin=2</i></div>
<div class=""><i class=""> ! starting_magnetization(1)=0.1</i></div>
<div class=""><i class="">! Hf 95.94 Hf.pbe-mt_fhi.UPF</i></div>
<div class=""><i class="">! S 32.065 S.pbe-mt_fhi.UPF</i></div>
<div class=""><i class="">/</i></div>
<div class=""><i class=""> &electrons</i></div>
<div class=""><i class=""> electron_dynamics='damp'</i></div>
<div class=""><i class="">! electron_velocities='zero'</i></div>
<div class=""><i class=""> emass=400</i></div>
<div class=""><i class=""> emass_cutoff=1</i></div>
<div class=""><i class=""> electron_damping=0.1</i></div>
<div class=""><i class="">/</i></div>
<div class=""><i class=""> &ions</i></div>
<div class=""><i class=""> ion_dynamics = 'damp'</i></div>
<div class=""><i class=""> ion_damping=0.1</i></div>
<div class=""><i class=""> ion_nstepe=10</i></div>
<div class=""><i class=""> /</i></div>
<div class=""><i class=""> &cell</i></div>
<div class=""><i class=""> cell_dynamics = 'none'</i></div>
<div class=""><i class=""> </i></div>
<div class=""><i class="">/</i></div>
<div class=""><i class="">ATOMIC_SPECIES</i></div>
<div class=""><i class=""> Hf 95.94 Hf.pbe-mt_fhi.UPF</i></div>
<div class=""><i class=""> S 32.065 S.pbe-mt_fhi.UPF</i></div>
<div class=""><i class="">ATOMIC_POSITIONS (crystal)</i></div>
<div class=""><i class="">Hf -0.000000000 -0.000000000 -0.000000000</i></div>
<div class=""><i class="">S 0.666666667 0.333333333 0.257234636</i></div>
<div class=""><i class="">S 0.333333333 0.666666667 -0.257234636</i></div>
<div class=""><i class=""> K_POINTS automatic</i></div>
<div class=""><i class="">10 8 8 0 0 0</i></div>
<div style="font-weight:bold" class=""><br class="">
</div>
</div>
<div style="font-weight:bold" class="">Cell relaxation</div>
<div class="">
<div class=""><i class="">&control</i></div>
<div class=""><i class=""> calculation='vc-cp',</i></div>
<div class=""><i class=""> title='Halfnium disulfide'</i></div>
<div class=""><i class=""> restart_mode='reset_counters',</i></div>
<div class=""><i class=""> ndr=51,</i></div>
<div class=""><i class=""> ndw=52,</i></div>
<div class=""><i class=""> nstep=50000,</i></div>
<div class=""><i class=""> iprint=100</i></div>
<div class=""><i class=""> isave=100,</i></div>
<div class=""><i class=""> tstress = .true.</i></div>
<div class=""><i class=""> tprnfor = .true.</i></div>
<div class=""><i class=""> dt=10,</i></div>
<div class=""><i class=""> wf_collect=.true.</i></div>
<div class=""><i class=""> etot_conv_thr=1e-6</i></div>
<div class=""><i class=""> forc_conv_thr=1e-3</i></div>
<div class=""><i class=""> ekin_conv_thr=1e-5</i></div>
<div class=""><i class=""> prefix='HfS2',</i></div>
<div class=""><i class=""> pseudo_dir='/home/jpeng/HfS2/<wbr class="">potential'</i></div>
<div class=""><i class=""> outdir='./tmp/',</i></div>
<div class=""><i class=""> /</i></div>
<div class=""><i class=""> &system</i></div>
<div class=""><i class=""> ibrav= 4,</i></div>
<div class=""><i class=""> a=3.6529</i></div>
<div class=""><i class=""> c=5.6544</i></div>
<div class=""><i class=""> nat= 3, ntyp= 2,</i></div>
<div class=""><i class=""> ecutwfc =50</i></div>
<div class=""><i class=""> vdw_corr='DFT-D',</i></div>
<div class=""><i class=""> ! lspinorb=.true.</i></div>
<div class=""><i class=""> ! noncolin=.true.</i></div>
<div class=""><i class=""> ! ecutrho=300</i></div>
<div class=""><i class=""> ! nbnd=14</i></div>
<div class=""><i class="">! occupations='smearing'</i></div>
<div class=""><i class="">! smearing='gaussian'</i></div>
<div class=""><i class="">! degauss=0.01</i></div>
<div class=""><i class=""> ! nspin=2</i></div>
<div class=""><i class=""> ! starting_magnetization(1)=0.1</i></div>
<div class=""><i class="">! Hf 95.94 Hf.pbe-mt_fhi.UPF</i></div>
<div class=""><i class="">! S 32.065 S.pbe-mt_fhi.UPF</i></div>
<div class=""><i class="">/</i></div>
<div class=""><i class=""> &electrons</i></div>
<div class=""><i class=""> electron_dynamics='damp'</i></div>
<div class=""><i class="">! electron_velocities='zero'</i></div>
<div class=""><i class=""> emass=400</i></div>
<div class=""><i class=""> emass_cutoff=1</i></div>
<div class=""><i class=""> electron_damping=0.1</i></div>
<div class=""><i class="">/</i></div>
<div class=""><i class=""> &ions</i></div>
<div class=""><i class=""> ion_dynamics = 'damp'</i></div>
<div class=""><i class=""> ion_damping=0.1</i></div>
<div class=""><i class=""> ion_nstepe=10</i></div>
<div class=""><i class=""> /</i></div>
<div class=""><i class=""> &cell</i></div>
<div class=""><i class=""> cell_dynamics = 'pr'</i></div>
<div class=""><i class="">! cell_damping=0.1</i></div>
<div class=""><i class="">! cell_dofree=volume</i></div>
<div class=""><i class="">/</i></div>
<div class=""><i class="">ATOMIC_SPECIES</i></div>
<div class=""><i class=""> Hf 95.94 Hf.pbe-mt_fhi.UPF</i></div>
<div class=""><i class=""> S 32.065 S.pbe-mt_fhi.UPF</i></div>
<div class=""><i class="">ATOMIC_POSITIONS (crystal)</i></div>
<div class=""><i class="">Hf -0.000000000 -0.000000000 -0.000000000</i></div>
<div class=""><i class="">S 0.666666667 0.333333333 0.257234636</i></div>
<div class=""><i class="">S 0.333333333 0.666666667 -0.257234636</i></div>
<div class=""><i class=""> K_POINTS automatic</i></div>
<div class=""><i class="">10 8 8 0 0 0</i></div>
<div style="font-weight:bold" class=""><br class="">
</div>
</div>
<div style="font-weight:bold" class="">The final equilibrium lattice
structure obtained by cp.x is:</div>
<div class="">
<div class=""><b class=""> </b><i class=""> CELL_PARAMETERS</i></div>
<div class=""><i class=""> 8.27944202 -3.49986616 -1.28541441</i></div>
<div class=""><i class=""> 0.43381045 6.25063702 -0.26433640</i></div>
<div class=""><i class=""> -1.81611680 -0.30736678 9.28229385</i></div>
<div class=""><i class=""><br class="">
</i></div>
<div class=""><i class=""> System Density [g/cm^3] :
3.7550323993</i></div>
<div class=""><i class=""><br class="">
</i></div>
<div class=""><i class=""><br class="">
</i></div>
<div class=""><i class=""> System Volume [A.U.^3] :
477.6950599279</i></div>
<div class=""><i class=""><br class="">
</i></div>
<div class=""><i class=""><br class="">
</i></div>
<div class=""><i class=""> Center of mass square displacement (a.u.):
0.271737</i></div>
<div class=""><i class=""><br class="">
</i></div>
<div class=""><i class=""> Total stress (GPa)</i></div>
<div class=""><i class=""> -0.00003957 0.00000336
0.00017132</i></div>
<div class=""><i class=""> 0.00000336 -0.00001393
0.00003875</i></div>
<div class=""><i class=""> 0.00017132 0.00003875
0.00048005</i></div>
<div class=""><i class=""> ATOMIC_POSITIONS</i></div>
<div class=""><i class=""> Hf -0.57392945538368E+00
-0.32523714658422E+00 -0.78842946683202E-01</i></div>
<div class=""><i class=""> S 0.61817237992192E+01
0.34715217744206E+01 0.20852180260292E+00</i></div>
<div class=""><i class=""> S 0.31507619982481E+00
0.41860506478142E+01 -0.20961035507250E+01</i></div>
<div class=""><i class=""><br class="">
</i></div>
<div class=""><i class=""> ATOMIC_VELOCITIES</i></div>
<div class=""><i class=""> Hf -0.49417894612947E-07
-0.41246570825668E-07 -0.28182774835127E-06</i></div>
<div class=""><i class=""> S 0.29443574450584E-06
0.17988901894696E-06 0.34817154465079E-06</i></div>
<div class=""><i class=""> S -0.14657506118618E-06
-0.56477323752712E-07 0.49507043808484E-06</i></div>
<div class=""><i class=""><br class="">
</i></div>
<div class=""><i class=""> Forces acting on atoms (au):</i></div>
<div class=""><i class=""> Hf -0.18727766763523E-03
-0.15291863668542E-03 -0.99976280595181E-03</i></div>
<div class=""><i class=""> S 0.33856074345196E-03
0.20689440901408E-03 0.40153992932368E-03</i></div>
<div class=""><i class=""> S -0.17602213243772E-03
-0.68887225779463E-04 0.57298561574671E-03</i></div>
<div class=""><i class=""><br class="">
</i></div>
<div class="">A visualization is attached here </div>
<div style="font-weight:bold" class="">
<span id="cid:part1.C12A770C.5B57FD7A@sissa.it"><image.png></span>
<br class="">
<br class="">
</div>
</div>
<div style="font-weight:bold" class="">while by pwscf, the equilibrium
lattice structure is:</div>
<div class="">
<div class=""><i class=""> CELL_PARAMETERS</i></div>
<div class=""><i class=""> 6.90298059 -3.45149030 0.00000000</i></div>
<div class=""><i class=""> 0.00000000 5.97815655 0.00000000</i></div>
<div class=""><i class=""> 0.00000000 0.00000000 10.68526745</i></div>
<div class=""><i class=""><br class="">
</i></div>
<div class=""><i class=""> System Density [g/cm^3] :
4.0679453101</i></div>
<div class=""><i class=""><br class="">
</i></div>
<div class=""><i class=""><br class="">
</i></div>
<div class=""><i class=""> System Volume [A.U.^3] :
440.9499858676</i></div>
<div class=""><i class=""><br class="">
</i></div>
<div class=""><i class=""><br class="">
</i></div>
<div class=""><i class=""> Center of mass square displacement (a.u.):
0.000000</i></div>
<div class=""><i class=""><br class="">
</i></div>
<div class=""><i class=""> Total stress (GPa)</i></div>
<div class=""><i class=""> 32.06481501 -0.01335027
-0.00956254</i></div>
<div class=""><i class=""> -0.01335027 32.07951164
-0.00592770</i></div>
<div class=""><i class=""> -0.00956139 -0.00592704
2.04176052</i></div>
<div class=""><i class=""> ATOMIC_POSITIONS</i></div>
<div class=""><i class=""> Hf 0.00000000000000E+00
-0.00000000000000E+00 -0.00000000000000E+00</i></div>
<div class=""><i class=""> S 0.34514902988605E+01
0.19927188491672E+01 0.27486208819801E+01</i></div>
<div class=""><i class=""> S -0.34514902047533E-08
0.39854377043125E+01 -0.27486208819801E+01</i></div>
<div class=""><i class=""><br class="">
</i></div>
<div class=""><i class=""> ATOMIC_VELOCITIES</i></div>
<div class=""><i class=""> Hf 0.00000000000000E+00
0.00000000000000E+00 0.00000000000000E+00</i></div>
<div class=""><i class=""> S 0.00000000000000E+00
0.00000000000000E+00 0.00000000000000E+00</i></div>
<div class=""><i class=""> S 0.00000000000000E+00
0.00000000000000E+00 0.00000000000000E+00</i></div>
<div class=""><i class=""><br class="">
</i></div>
<div class=""><i class=""> Forces acting on atoms (au):</i></div>
<div class=""><i class=""> Hf 0.70847502228925E-03
0.43071957102166E-03 -0.17703368862259E-04</i></div>
<div class=""><i class=""> S -0.52668423530029E-03
-0.28607208606422E-03 -0.81547327015321E-01</i></div>
<div class=""><i class=""> S -0.41998284595312E-03
-0.22039679837681E-03 0.81837284893753E-01</i></div>
<div style="font-weight:bold" class=""><br class="">
</div>
</div>
<div class="">A visulization is attached below</div>
<div class="">
<span id="cid:part2.BDAE1642.F544B821@sissa.it"><image.png></span>
<br class="">
</div>
<div style="font-weight:bold" class=""><br class="">
</div>
<div style="font-weight:bold" class=""><br class="">
</div>
<div class="">I am expecting some difference because pw.x uses
DFT and BFGS algorithm to relax the lattice structure while
cp.x uses CP method, but not so large a difference.
Especially since the lattice structure given by pw.x agrees
with experiments and other published works, I am suspecting
is it because I have not correctly carried out variable cell
CP simulations. </div>
<div class=""><br class="">
</div>
<div class="">Can anyone help me understand the discrepancy I
see in the results produced by pw.x and cp.x code? Or
pointing out any mistake I have made during my simulations?</div>
<div class=""><br class="">
</div>
<div class="">Thank you in advance for your help, sincerely!<br class="">
<br class="">
</div>
<div class="">Best</div>
<div class="">Jie</div>
-- <br class="">
<div class="m_4773530265834723698gmail_signature">
<div dir="ltr" class="">
<div class="">
<div style="font-size:12.8px" class="">------------------------------<wbr class="">------------------------------<wbr class="">------------------------------<wbr class="">------------------------------<br class="">
Jie Peng</div>
<div style="font-size:12.8px" class="">PhD student<br class="">
2134 Glenn Martin Hall, Mechanical Engineering,
University of Maryland<br class="">
College Park, Maryland, USA<br class="">
Phone:(+1) 240-495-9445<br class="">
</div>
<div style="font-size:12.8px" class="">Email: <a href="mailto:jiepeng@umd.edu" target="_blank" class="">jiepeng@umd.edu</a><br class="">
</div>
</div>
<div class=""><br class="">
</div>
</div>
</div>
</div>
</div>
<br class="">
<fieldset class="m_4773530265834723698mimeAttachmentHeader"></fieldset>
<br class="">
</div></div><pre class="">______________________________<wbr class="">_________________
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