<div dir="ltr">Dear users and developers,<div><br><div>I am using QE v7.0 and trying to investigate the superconductivity of a 2D material. I have used the PBE pseudopotential from PSlibrary and took Kmesh 36x36x1.</div><div>After vc-relax, the resulted forces and stress are:</div><div><br></div><div> <b>Total force = 0.000014 Total SCF correction = 0.000001<br><br><br> Computing stress (Cartesian axis) and pressure<br><br><br> negative rho (up, down): 1.001E-01 0.000E+00<br> total stress (Ry/bohr**3) (kbar) P= -0.10</b><br></div><div><br></div><div>Are these values acceptable? Do I need to reduce these values?</div><div><br></div><div>Here a typical <a href="http://ph.in">ph.in</a> file I use:<br></div><div><br></div><div><b>title_line<br>&inputph<br> prefix = 'W2F2',<br> fildyn = 'W2F2.dyn',<br> amass(1) = 18.9984032,<br> amass(2) = 183.84,<br> outdir = './'<br> ldisp = .true.,<br> trans = .true.,<br> fildvscf = 'dvscf',<br> search_sym=.FALSE.,<br> alpha_mix(1) = 0.2,<br> nq1=3,<br> nq2=3,<br> nq3=1,<br> tr2_ph = 1.0d-12<br>/</b><br></div><div> </div><div>When I ran <a href="http://ph.in">ph.in</a> by adding "<b>alpha_mix flag"</b>, I am getting<b> no imaginary frequencies</b>, but the lambda.out file shows NaN</div><div><br></div><div> <b>lambda = 0.835778 ( NaN ) <log w>= NaN K N(Ef)= 11.024689 at degauss= 0.005<br> lambda = 0.598189 ( NaN ) <log w>= NaN K N(Ef)= 10.196114 at degauss= 0.010<br> lambda = 0.526611 ( NaN ) <log w>= NaN K N(Ef)= 9.481577 at degauss= 0.015<br> lambda = 0.485222 ( NaN ) <log w>= NaN K N(Ef)= 8.817546 at degauss= 0.020<br> lambda = 0.465900 ( NaN ) <log w>= NaN K N(Ef)= 8.336884 at degauss= 0.025<br> lambda = 0.466822 ( NaN ) <log w>= NaN K N(Ef)= 8.111690 at degauss= 0.030<br> lambda = 0.481500 ( NaN ) <log w>= NaN K N(Ef)= 8.111006 at degauss= 0.035<br> lambda = 0.504944 ( NaN ) <log w>= NaN K N(Ef)= 8.267627 at degauss= 0.040<br> lambda = 0.532578 ( NaN ) <log w>= NaN K N(Ef)= 8.520600 at degauss= 0.045<br> lambda = 0.562378 ( NaN ) <log w>= NaN K N(Ef)= 8.823055 at degauss= 0.050<br>lambda omega_log T_c<br> 0.83578 NaN NaN<br> 0.59819 NaN NaN<br> 0.52661 NaN NaN<br> 0.48522 NaN NaN<br> 0.46590 NaN NaN<br> 0.46682 NaN NaN<br> 0.48150 NaN NaN<br> 0.50494 NaN NaN<br> 0.53258 NaN NaN</b><br> <b> 0.56238 NaN NaN</b><br></div><div><b><br></b></div><div>And when I ran <a href="http://ph.in">ph.in</a> <b>without alpha_mix flag</b>, there were imaginary frequencies in the phonon dispersion and I am getting values in lambda.out file</div><div><br></div><div> <b>lambda = 0.760811 ( 0.760801 ) <log w>= 197.892 K N(Ef)= 11.024689 at degauss= 0.005<br> lambda = 0.573322 ( 0.573317 ) <log w>= 188.429 K N(Ef)= 10.196114 at degauss= 0.010<br> lambda = 0.520900 ( 0.520896 ) <log w>= 184.554 K N(Ef)= 9.481577 at degauss= 0.015<br> lambda = 0.488111 ( 0.488108 ) <log w>= 183.224 K N(Ef)= 8.817546 at degauss= 0.020<br> lambda = 0.474378 ( 0.474375 ) <log w>= 182.309 K N(Ef)= 8.336884 at degauss= 0.025<br> lambda = 0.481178 ( 0.481175 ) <log w>= 181.389 K N(Ef)= 8.111690 at degauss= 0.030<br> lambda = 0.502378 ( 0.502375 ) <log w>= 180.618 K N(Ef)= 8.111006 at degauss= 0.035<br> lambda = 0.533389 ( 0.533386 ) <log w>= 180.243 K N(Ef)= 8.267627 at degauss= 0.040<br> lambda = 0.569867 ( 0.569863 ) <log w>= 180.075 K N(Ef)= 8.520600 at degauss= 0.045<br> lambda = 0.608489 ( 0.608486 ) <log w>= 180.009 K N(Ef)= 8.823055 at degauss= 0.050</b><br><b>lambda omega_log T_c<br> 0.76081 197.892 7.177<br> 0.57332 188.429 2.921<br> 0.52090 184.554 1.950<br> 0.48811 183.224 1.439<br> 0.47438 182.309 1.243<br> 0.48118 181.389 1.329<br> 0.50238 180.618 1.624<br> 0.53339 180.243 2.106<br> 0.56987 180.075 2.730<br> 0.60849 180.009 3.443</b><br><br></div><div><br class="gmail-Apple-interchange-newline"><span style="color:rgb(0,0,0)">Could anyone tell me what was going wrong here.</span><br></div><div>Kindly help me to fix this.<br></div><div><br></div><div>Thank you.</div><div>Regards</div><div>Prarena Jamwal</div><div>Research Scholar</div><div>IIT Ropar, INDIA.</div></div></div>
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