Dear All, <div><br></div><div>I also have a question about vc-relax. How do you know if your cutoff is large enough to overcome Pulay stress, or you can do something else to get rid of it in you calculations. Thanks.</div>
<div><br></div><div>Best Wishes</div><div>jia<br><br><div class="gmail_quote">On Wed, Jan 19, 2011 at 11:57 AM, mohnish pandey <span dir="ltr"><<a href="mailto:mohnish.iitk@gmail.com">mohnish.iitk@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 QE users,<div> I am trying to do bulk calculations for MnSe in rocksalt and wurtzite structure. Its has AFM ground state in rocksalt structure but after checking convergence I am finding "rocksalt" structure to be energetically higher than wurtzite structure. I am pasting my segments of input and output files. Can anybody please help me in figuring out the problem. </div>
<div><br></div><div><b>INPUT FOR ROCKSALT</b></div><div><br></div><div><div>&control</div><div> calculation = 'vc-relax'</div><div> restart_mode='restart',</div><div> wf_collect = .true.</div>
<div> prefix='mnse',</div><div> pseudo_dir = '/home/mohnish/mnse-rocksalt-bulk',</div><div> outdir='/home/mohnish/mnse-rocksalt-bulk',</div><div> tprnfor = .true., </div><div> tstress=.true.</div>
<div> /</div><div> &system</div><div> ibrav= 0, celldm(1)= 10.3026, nat= 4, ntyp= 3,</div><div> ecutwfc = 40.0, ecutrho = 320.0, </div><div> occupations='smearing', smearing='gauss', degauss=0.01,</div>
<div> nspin=2,</div><div> starting_magnetization(1)= 0.0,</div><div> starting_magnetization(2)= 0.5,</div><div> starting_magnetization(3)=-0.5,</div><div> /</div><div> &electrons</div><div> diagonalization='david'</div>
<div> mixing_mode = 'plain'</div><div> mixing_beta = 0.4</div><div> conv_thr = 1.0d-8</div><div> startingpot = 'file'</div><div> startingwfc = 'file'</div><div> /</div><div>&IONS</div>
<div> ion_dynamics='bfgs'</div><div> trust_radius_max = 0.40</div><div> trust_radius_ini = 0.20</div><div>/</div><div>&CELL</div><div> cell_dynamics='bfgs',</div><div>/</div><div>ATOMIC_SPECIES</div>
<div> Se 78.960 Se.pbe-van.UPF</div><div> Mn1 54.938 Mn.pbe-sp-van_mit.UPF</div><div> Mn2 54.938 Mn.pbe-sp-van_mit.UPF</div><div>CELL_PARAMETERS</div><div>0.50 0.50 1.00</div><div>0.50 1.00 0.50</div><div>1.00 0.50 0.50</div>
<div>ATOMIC_POSITIONS {crystal}</div><div> Se 0.25 0.25 0.25</div><div> Se 0.75 0.75 0.75</div><div> Mn1 0.0 0.0 0.0</div><div> Mn2 0.5 0.5 0.5</div><div>K_POINTS {automatic}</div><div>6 6 6 0 0 0</div></div><div><br>
</div><div><b>OUTPUT FOR ROCKSALT</b></div><div><br></div><div><div> bfgs converged in 8 scf cycles and 4 bfgs steps</div><div> (criteria: energy < 0.10E-03, force < 0.10E-02, cell < 0.50E+00)</div>
<div><br></div><div> End of BFGS Geometry Optimization</div><div><br></div><div> Final enthalpy = -464.4688263706 Ry</div><div>Begin final coordinates</div><div> new unit-cell volume = 533.55466 a.u.^3 ( 79.06464 Ang^3 )</div>
<div><br></div><div>CELL_PARAMETERS (alat= 10.30260000)</div><div> 0.494008772 0.494008772 0.990589056</div><div> 0.494008772 0.990589056 0.494008772</div><div> 0.990589056 0.494008772 0.494008772</div>
<div>
<br></div><div>ATOMIC_POSITIONS (crystal)</div><div>Se 0.249999854 0.249999854 0.249999854</div><div>Se 0.750000146 0.750000146 0.750000146</div><div>Mn1 0.000000000 0.000000000 0.000000000</div>
<div>Mn2 0.500000000 0.500000000 0.500000000</div><div>End final coordinates</div><div><br></div><div><b>INPUT FOR WURTZITE</b></div><div><br></div><div><div>&control</div><div> calculation = 'vc-relax',</div>
<div> restart_mode='restart',</div><div> verbosity = 'high'</div><div> wf_collect = .true.</div><div> outdir='/home/mohnish/mnse-wurtzite-bulk',</div><div> pseudo_dir='/home/mohnish/mnse-wurtzite-bulk'</div>
<div> prefix='mnse',</div><div> tstress = .true.,</div><div> tprnfor = .true.,</div><div>/</div><div> &system </div><div> ibrav= 4, a = 4.178, c = 6.783,nat= 4, ntyp= 3,</div><div> ecutwfc = 40,ecutrho=320,occupations='smearing',degauss=0.01,smearing='gaussian',</div>
<div> nspin =2,starting_magnetization(1)=0.5,starting_magnetization(2)= -0.5, </div><div>/</div><div> &electrons</div><div> diagonalization='david'</div><div> mixing_mode = 'plain'</div><div> mixing_beta = 0.4</div>
<div> conv_thr = 1.0d-8</div><div> startingpot = 'file'</div><div> startingwfc = 'file'</div><div> /</div><div>&IONS</div><div> ion_dynamics='bfgs'</div><div> trust_radius_max = 0.40</div>
<div> trust_radius_ini = 0.20</div><div>/</div><div>&CELL</div><div> cell_dynamics='bfgs',</div><div>/</div><div>ATOMIC_SPECIES</div><div> Mn1 54.938 Mn.pbe-sp-van_mit.UPF</div><div> Mn2 54.938 Mn.pbe-sp-van_mit.UPF</div>
<div> Se 78.960 Se.pbe-van.UPF</div><div>ATOMIC_POSITIONS (crystal)</div><div> Mn1 0.000000000 0.000000000000 0.000000000 </div><div> Mn2 0.333333333 0.666666666667 0.500000000</div><div> Se 0.000000000 0.000000000000 0.345000000 </div>
<div> Se 0.333333333 0.666666666667 0.845000000 </div><div> K_POINTS (automatic)</div><div> 6 6 4 0 0 0</div><div><br></div><div><b>OUTPUT FOR WURTZITE</b></div><div><br></div><div><div> End of BFGS Geometry Optimization</div>
<div><br></div><div> Final enthalpy = -464.4799667612 Ry</div><div>Begin final coordinates</div><div> new unit-cell volume = 681.36082 a.u.^3 ( 100.96726 Ang^3 )</div><div><br></div><div>CELL_PARAMETERS (alat= 7.89527578)</div>
<div> 1.001414763 0.000000000 0.000000000</div><div> -0.500707382 0.867250625 0.000000000</div><div> 0.000000000 0.000000000 1.594103933</div><div><br></div><div>ATOMIC_POSITIONS (crystal)</div><div>Mn1 0.000000000 0.000000000 -0.014999731</div>
<div>Mn2 0.333333333 0.666666667 0.485592670</div><div>Se 0.000000000 0.000000000 0.359333481</div><div>Se 0.333333333 0.666666667 0.860073579</div><div>End final coordinates</div><div><br></div>
</div><div><br></div><div><br></div><div><br></div><div> </div></div>-- <br>Regards,<br>MOHNISH,<br>-----------------------------------------------------------------<br>Mohnish Pandey<br>Y6927262,5th Year dual degree student,<br>
Department of Chemical Engineering,<br>IIT KANPUR, UP, INDIA<br>-----------------------------------------------------------------<br>
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<br></blockquote></div><br><br clear="all"><br>-- <br>Jia Chen<br><br><br>
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