<div dir="ltr"><div>There are two sets of "differences" in your calculations:</div><div>- the three lowest frequencies of the acoustic mode</div><div>- symmetry labels B_2 and B_3. <br></div><div>I don't know about the latter, but the former difference reflects an algorithmic difference: the Gamma-only code (phcg.x) imposes acoustic sum rule during the calculation, while the ordinary phonon code (ph.x) doesn't. Nothing to worry about.</div><div><br></div><div>Paolo<br></div></div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Wed, Oct 30, 2019 at 3:16 AM wang1968000 <<a href="mailto:wang1968000@163.com">wang1968000@163.com</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div style="line-height:1.7;color:rgb(0,0,0);font-size:14px;font-family:Arial"><div>Hi. QE users.</div><div>I have calculate Gamma point phonon and phonon dispersion on black phosphorus.</div><div>But the phonon modes are not same in only Gamma point calculation and several q point calculations.</div><div><br></div><div>This is the results coming from only Gamma point calculation.</div><div><div> Diagonalizing the dynamical matrix</div><div><br></div><div> q = ( 0.000000000 0.000000000 0.000000000 ) </div><div><br></div><div> **************************************************************************</div><div> freq ( 1) = -0.038897 [THz] = -1.297458 [cm-1]</div><div> freq ( 2) = -0.031677 [THz] = -1.056638 [cm-1]</div><div> freq ( 3) = 0.027926 [THz] = 0.931519 [cm-1]</div><div> freq ( 4) = 2.928955 [THz] = 97.699418 [cm-1]</div><div> freq ( 5) = 5.638698 [THz] = 188.086708 [cm-1]</div><div> freq ( 6) = 6.639162 [THz] = 221.458590 [cm-1]</div><div> freq ( 7) = 10.953491 [THz] = 365.369131 [cm-1]</div><div> freq ( 8) = 12.684841 [THz] = 423.120746 [cm-1]</div><div> freq ( 9) = 12.722708 [THz] = 424.383866 [cm-1]</div><div> freq ( 10) = 12.745234 [THz] = 425.135234 [cm-1]</div><div> freq ( 11) = 13.570613 [THz] = 452.666939 [cm-1]</div><div> freq ( 12) = 13.874216 [THz] = 462.794044 [cm-1]</div><div> **************************************************************************</div><div><br></div><div> Mode symmetry, D_2h (mmm) point group:</div><div><br></div><div> freq ( 1 - 1) = -1.3 [cm-1] --> B_3u I </div><div> freq ( 2 - 2) = -1.1 [cm-1] --> B_1u I </div><div> freq ( 3 - 3) = 0.9 [cm-1] --> B_2u I </div><div> freq ( 4 - 4) = 97.7 [cm-1] --> B_3u I </div><div> freq ( 5 - 5) = 188.1 [cm-1] --> B_3g R </div><div> freq ( 6 - 6) = 221.5 [cm-1] --> B_2g R </div><div> freq ( 7 - 7) = 365.4 [cm-1] --> A_g R </div><div> freq ( 8 - 8) = 423.1 [cm-1] --> A_u </div><div> freq ( 9 - 9) = 424.4 [cm-1] --> B_1g R </div><div> freq ( 10 - 10) = 425.1 [cm-1] --> B_2g R </div><div> freq ( 11 - 11) = 452.7 [cm-1] --> A_g R </div><div> freq ( 12 - 12) = 462.8 [cm-1] --> B_1u I </div></div><div><br></div><div><br></div><div>This results comes from Gamma point in several q point calculation.</div><div> q = ( 0.000000000 0.000000000 0.000000000 ) </div><div><br></div><div> **************************************************************************</div><div> freq ( 1) = 0.294821 [THz] = 9.834157 [cm-1]</div><div> freq ( 2) = 0.531839 [THz] = 17.740255 [cm-1]</div><div> freq ( 3) = 0.538183 [THz] = 17.951848 [cm-1]</div><div> freq ( 4) = 2.934902 [THz] = 97.897792 [cm-1]</div><div> freq ( 5) = 5.651273 [THz] = 188.506166 [cm-1]</div><div> freq ( 6) = 6.641297 [THz] = 221.529834 [cm-1]</div><div> freq ( 7) = 10.953478 [THz] = 365.368700 [cm-1]</div><div> freq ( 8) = 12.689602 [THz] = 423.279546 [cm-1]</div><div> freq ( 9) = 12.724636 [THz] = 424.448167 [cm-1]</div><div> freq ( 10) = 12.750003 [THz] = 425.294313 [cm-1]</div><div> freq ( 11) = 13.570944 [THz] = 452.677974 [cm-1]</div><div> freq ( 12) = 13.879876 [THz] = 462.982823 [cm-1]</div><div> **************************************************************************</div><div><br></div><div> Mode symmetry, D_2h (mmm) point group:</div><div><br></div><div> freq ( 1 - 1) = 9.8 [cm-1] --> B_1u I </div><div> freq ( 2 - 2) = 17.7 [cm-1] --> B_3u I </div><div> freq ( 3 - 3) = 18.0 [cm-1] --> B_2u I </div><div> freq ( 4 - 4) = 97.9 [cm-1] --> B_2u I </div><div> freq ( 5 - 5) = 188.5 [cm-1] --> B_2g R </div><div> freq ( 6 - 6) = 221.5 [cm-1] --> B_3g R </div><div> freq ( 7 - 7) = 365.4 [cm-1] --> A_g R </div><div> freq ( 8 - 8) = 423.3 [cm-1] --> A_u </div><div> freq ( 9 - 9) = 424.4 [cm-1] --> B_1g R </div><div> freq ( 10 - 10) = 425.3 [cm-1] --> B_3g R </div><div> freq ( 11 - 11) = 452.7 [cm-1] --> A_g R </div><div> freq ( 12 - 12) = 463.0 [cm-1] --> B_1u I </div><div><br></div><div><br></div><div>Why these two parts are not same?</div><div>The structure I already optimised.</div><div><br></div><div>TW.</div><div>Department of Physics</div><div>Tohoku Unviersity</div><div>Email: <a href="mailto:wang1968000@163.com" target="_blank">wang1968000@163.com</a></div><div><br></div></div><br><br><span title="neteasefooter"><p> </p></span>_______________________________________________<br>
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