<div dir="ltr"><div dir="ltr">On Fri, Nov 6, 2020 at 11:14 PM Ashis Kundu <<a href="mailto:ashiskundu174@gmail.com">ashiskundu174@gmail.com</a>> wrote:</div><div dir="ltr"><br></div><div class="gmail_quote"><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div dir="ltr">Why is there a mismatch between k-points from SCF and q-point from system.dyn0 (phonon calculation)? <div><div>[...] Ideally they should be the same</div></div></div></blockquote><div><br></div><div>they are the same, but the algorithms for generation and selection of the irreducible sector are different for the two grids so the ordering and sign may differ. Each of the points in the first set is either equal to or equivalent to a point of the second set.<br></div><div><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 dir="ltr"><div><div>Please let me know if I am doing something wrong.</div></div></div></blockquote><div><br></div><div>you aren't doing anything wrong. Or maybe you are: the scf input you sent cannot produce the k-point grid you listed</div><div><br></div><div>Paolo<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 dir="ltr"><div><div><br></div><div>The k-points generated from SCF </div><div><br></div><div> number of k points= 8 Methfessel-Paxton smearing, width (Ry)= 0.0200<br> cart. coord. in units 2pi/alat<br> k( 1) = ( 0.0000000 0.0000000 0.0000000), wk = 0.0740741<br> k( 2) = ( -0.3333333 0.0000000 0.0977788), wk = 0.2962963<br> k( 3) = ( -0.3333333 0.3333333 0.1955577), wk = 0.5925926<br> k( 4) = ( 0.3333333 0.3333333 -0.0000000), wk = 0.2962963<br> k( 5) = ( 0.0000000 0.0000000 0.1955577), wk = 0.1481481<br> k( 6) = ( 0.6666667 0.0000000 -0.0000000), wk = 0.1481481<br> k( 7) = ( 0.0000000 -0.3333333 -0.0977788), wk = 0.2962963<br> k( 8) = ( 0.0000000 0.6666667 0.0000000), wk = 0.1481481<br></div><div><br></div><div>q-point from phonon calculations (a mesh of 3x3x3 is used)</div><div><br></div><div>0.00000000 0.00000000 0.00000000<br>-0.33333333 0.00000000 0.09777884<br>0.00000000 0.33333333 0.09777884<br>-0.33333333 0.33333333 0.19555767<br>0.33333333 0.33333333 -0.00000000<br>0.00000000 0.00000000 0.19555767<br>0.66666667 0.00000000 -0.00000000<br>0.00000000 -0.66666667 -0.00000000<br></div><div><br></div><div>Below are the SCF and phonon input file</div><div><br></div><div><a href="http://scf.in/" target="_blank">scf.in</a></div><div>-----</div><div>&control<br> calculation = 'scf'<br> prefix = 'TaP'<br> pseudo_dir = '../pp'<br> outdir = './'<br> wf_collect = .true.<br> tprnfor = .true.<br> tstress = .true.<br> /<br> &system<br> ibrav = 7<br> celldm(1) = 6.173529611<br> celldm(3) = 3.409054<br> nat = 4<br> ntyp = 2<br> ecutwfc = 100<br> occupations = 'smearing'<br> smearing = 'mp'<br> degauss = 0.02<br> /<br> &electrons<br> diagonalization = 'david'<br> mixing_beta = 0.7<br> conv_thr = 1.0d-10<br> /<br>ATOMIC_SPECIES<br> Ta 180.948 Ta.pw-mt_fhi.UPF<br> P 30.974 P.pw-mt_fhi.UPF<br>ATOMIC_POSITIONS {alat}<br>Ta 0.0000000 0.0000000 -0.0044625<br>Ta 0.0000000 0.5000000 0.8478074<br>P 0.0000000 0.0000000 1.4178478<br>P 0.5000000 0.0000000 0.5655748<br>K_POINTS {automatic}<br> 15 15 15 0 0 0<br></div><div><br></div><div><a href="http://ph.in/" target="_blank">ph.in</a></div><div>----</div><div>phonon<br>&inputph<br> prefix = 'TaP'<br> fildyn = 'TaP.dyn'<br> fildvscf = 'dvscf' <br> ldisp = .true.<br> epsil = .false.<br> nq1 = 3<br> nq2 = 3<br> nq3 = 3<br> tr2_ph = 1.0d-14<br> /<br></div><div><br></div><div><br></div><div>Best regards,</div><div>Ashis</div></div></div>
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