<div dir="ltr">Dear Bhamu,<div><br></div><div>thank you for your email. My system is bulk CsPbBr3 and I do not have any problem with SCF self-convergence. Just the phonon calculation. Changing mixing_alpha did not lead to any significant improvement in my case....</div><div><br></div><div>Best,</div><div>Chris <br><div class="gmail_extra"><br><div class="gmail_quote">On Wed, Jun 27, 2018 at 9:23 PM, Dr. K. C. Bhamu <span dir="ltr"><<a href="mailto:kcbhamu85@gmail.com" target="_blank">kcbhamu85@gmail.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div dir="ltr"><br><div class="gmail_extra"><br clear="all"><div><div class="m_4078592912719155609gmail_signature" data-smartmail="gmail_signature"><div dir="ltr"><div><div dir="ltr"><div dir="ltr"><div dir="ltr"><div dir="ltr"><div><span style="font-size:12.8px">Hii Christoph,</span></div><div><span style="font-size:12.8px"><br></span></div><div><span style="font-size:12.8px">Could you please confirm whether your system is homogeneous or not?</span></div><div><span style="font-size:12.8px"><br></span></div><div dir="ltr"><span style="font-size:12.8px"><br></span></div><div><span style="font-size:12.8px">If it is not a homogeneous then 'local T-F' scheme will be the best one.</span></div><div><span style="font-size:12.8px"><br></span></div><div><span style="font-size:12.8px">I recently solved my problem by using local TF.</span></div><div><span style="font-size:12.8px"><br></span></div><div><span style="font-size:12.8px">Also, you can reduce mixing parameter to 0.3 from 0.7</span></div><div><span style="font-size:12.8px"><br></span></div><div><span style="font-size:12.8px"><br></span></div><div><span style="font-size:12.8px"><br></span></div><div><span style="font-size:12.8px">Kind regards</span></div><div><span style="font-size:12.8px">Bhamu<br></span></div><div dir="ltr"><span style="font-size:12.8px"><br></span></div><div dir="ltr"><span style="font-size:12.8px">Dr. K. C. Bhamu</span><br></div><div dir="ltr">National Postdoctoral Fellow,<br>Physical and Materials Chemistry Division</div><div dir="ltr">CSIR-NCl, Pune</div><div dir="ltr">India</div><div dir="ltr">Mob. No. +91-7888227869<br></div></div></div></div></div></div></div></div></div>
<br><div class="gmail_quote"><div><div class="h5">On Wed, Jun 27, 2018 at 5:46 PM, Christoph Wolf <span dir="ltr"><<a href="mailto:wolf.christoph@qns.science" target="_blank">wolf.christoph@qns.science</a>></span> wrote:<br></div></div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div><div class="h5"><div dir="ltr">Dear all,<div><br></div><div>I have recently encountered an "interesting phenomenon".</div><div><br></div><div>Let's say I have determined the (zone boundary phonon frequency) convergence parameter for a unit cell to be a k-grid of 6x6x6 and a ecutwfc=120 Ry. If I now take a 2x2x2 supercell of the material (using the relaxed cell as reference) I (naively) assumed that that would translate to a 3x3x3 k-grid, however I can never manage to converge phonons with that kind of setting as during the initial electric fields calculation the minimization will start to oscillate like this:</div><div><br></div><div><div><br></div><div> iter # 17 total cpu time : 8249.5 secs <a href="http://av.it" target="_blank">av.it</a>.: 1.8</div><div> thresh= 2.804E-05 alpha_mix = 0.700 |ddv_scf|^2 = 1.396E-07</div><div><br></div><div> iter # 18 total cpu time : 8353.6 secs <a href="http://av.it" target="_blank">av.it</a>.: 1.0</div><div> thresh= 3.737E-05 alpha_mix = 0.700 |ddv_scf|^2 = 1.506E-08</div><div><br></div><div> iter # 19 total cpu time : 8876.9 secs <a href="http://av.it" target="_blank">av.it</a>.: 15.4</div><div> thresh= 1.227E-05 alpha_mix = 0.700 |ddv_scf|^2 = 6.969E-08</div><div><br></div><div> iter # 20 total cpu time : 9303.8 secs <a href="http://av.it" target="_blank">av.it</a>.: 12.1</div><div> thresh= 2.640E-05 alpha_mix = 0.700 |ddv_scf|^2 = 6.076E-08</div><div><br></div><div> iter # 21 total cpu time : 9751.4 secs <a href="http://av.it" target="_blank">av.it</a>.: 12.9</div><div> thresh= 2.465E-05 alpha_mix = 0.700 |ddv_scf|^2 = 3.246E-08</div><div><br></div><div> iter # 22 total cpu time : 10145.8 secs <a href="http://av.it" target="_blank">av.it</a>.: 11.1</div><div> thresh= 1.802E-05 alpha_mix = 0.700 |ddv_scf|^2 = 3.519E-08</div><div><br></div><div> iter # 23 total cpu time : 10542.9 secs <a href="http://av.it" target="_blank">av.it</a>.: 11.2</div><div> thresh= 1.876E-05 alpha_mix = 0.700 |ddv_scf|^2 = 3.168E-09</div></div><div><br></div><div><br></div><div>Is this a common problem or am I doing something completely wrong...? </div><div><br></div><div>Your help is very much appreciated!</div><div><br></div><div>Best,</div><div>Chris </div><span class="m_4078592912719155609HOEnZb"><font color="#888888"><div><br></div><div>-- <br><div class="m_4078592912719155609m_-3537556625214627420gmail_signature"><div dir="ltr">Postdoctoral Researcher<br>Center for Quantum Nanoscience, Institute for Basic Science<br>Ewha Womans University, Seoul, South Korea<blockquote type="cite" style="font-size:12.8px"><div dir="ltr"><div><div dir="ltr"></div></div></div></blockquote></div></div>
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</blockquote></div><br><br clear="all"><div><br></div>-- <br><div class="gmail_signature" data-smartmail="gmail_signature"><div dir="ltr">Postdoctoral Researcher<br>Center for Quantum Nanoscience, Institute for Basic Science<br>Ewha Womans University, Seoul, South Korea<blockquote type="cite" style="font-size:12.8px"><div dir="ltr"><div><div dir="ltr"></div></div></div></blockquote></div></div>
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