<p style="font-family:SimSun;">
<span style="font-family:Microsoft YaHei;">Dear Paolo:</span>
</p>
<p style="font-family:SimSun;">
<span style="font-family:Microsoft YaHei;"><span style="font-family:Microsoft YaHei;"></span><span style="font-family:"Microsoft YaHei";">I have been trying to calculate phonon spectra using qe-7.2.</span></span>
</p>
<p style="font-family:SimSun;">
<span style="font-family:Microsoft YaHei;"><span style="font-family:SimSun;"><span style="font-family:Microsoft YaHei;">Although I am </span><span style="font-family:Microsoft YaHei;">able to calculate scf, I am facing a dilemma </span></span></span><span style="font-family:"Microsoft YaHei";">in case of ph.x. I could not get the same result by using different q mesh.</span><span style="font-family:Microsoft YaHei;"><span style="font-family:SimSun;"><span style="font-family:Microsoft YaHei;"><br>
</span><span style="font-family:Microsoft YaHei;">Please point out what's going wrong.</span></span></span>
</p>
<p>
<span style="font-family:'Microsoft YaHei';">scf.in</span>
</p>
<p>
<span style="font-family:'Microsoft YaHei';">'''</span>
</p>
<p>
<span style="font-family:'Microsoft YaHei';">&CONTROL<br>
calculation='scf',<br>
restart_mode='from_scratch',<br>
prefix='LaTe3',<br>
pseudo_dir='./',<br>
outdir='./',<br>
forc_conv_thr=1.0d-4<br>
/<br>
&SYSTEM<br>
ibrav = 0<br>
nat = 8<br>
ntyp = 2<br>
occupations = 'smearing'<br>
smearing='gauss'<br>
degauss=1.0d-3<br>
ecutwfc = 120<br>
/<br>
<br>
&ELECTRONS<br>
conv_thr=1.0d-9<br>
mixing_beta = 0.1<br>
/<br>
<br>
&IONS<br>
ion_dynamics='bfgs'<br>
/<br>
&CELL<br>
cell_dynamics='bfgs',<br>
press=0.0d0,<br>
press_conv_thr=0.5d0<br>
/<br>
<br>
ATOMIC_SPECIES<br>
La 138.9055 La.upf<br>
Te 127.60 Te.upf<br>
<br>
CELL_PARAMETERS (angstrom)<br>
4.431317771 0.000000000 0.000000000<br>
0.000000000 34.999576346 0.000000000<br>
0.000000000 0.000000000 4.432753002<br>
<br>
ATOMIC_POSITIONS (angstrom)<br>
La 2.2156588853 8.9820647540 3.3245647512<br>
La 0.0000000000 4.6716139523 1.1081882504<br>
Te 0.0000000000 2.0388582600 3.3245647512<br>
Te 2.2156588853 11.6148204058 1.1081882504<br>
Te 0.0000000000 11.6150595148 3.3245647512<br>
Te 2.2156588853 2.0386191329 1.1081882504<br>
Te 2.2156588853 5.6039485449 3.3245647512<br>
Te 0.0000000000 8.0497301558 1.1081882504<br>
<br>
K_POINTS automatic<br>
24 1 24 0 0 0<br>
</span>
</p>
<div style="white-space:nowrap;">
<br>
</div>
'''
<p>
<br>
</p>
<p>
<span style="font-family:'Microsoft YaHei';">when the q mesh is 1*1*1<br>
</span>
</p>
<p>
<span style="font-family:'Microsoft YaHei';">'''</span>
</p>
<p>
<span style="font-family:'Microsoft YaHei';">&INPUTPH<br>
outdir = './'<br>
prefix = 'LaTe3'<br>
fildvscf = 'dvscf'<br>
tr2_ph = 1.0d-14<br>
!nmix_ph = 4<br>
alpha_mix(1) = 0.1<br>
fildyn = 'LaTe3.dyn'<br>
ldisp = .true.<br>
nq1 = 1, nq2 = 1, nq3 = 1<br>
/<br>
</span>
</p>
<div>
'''
</div>
I got the result at gamma point.<br>
<p>
<br>
</p>
<p>
<span style="font-family:'Microsoft YaHei';">'''</span>
</p>
<p>
<span style="font-family:'Microsoft YaHei';"> q = ( 0.000000000 0.000000000 0.000000000 )<br>
<br>
**************************************************************************<br>
freq ( 1) = -1.302759 [THz] = -43.455374 [cm-1]<br>
( -0.000000 0.000000 0.422782 0.000000 0.000000 0.000000 )<br>
( 0.000000 0.000000 0.247942 0.000000 0.000000 0.000000 )<br>
( -0.000000 0.000000 0.126621 0.000000 0.000000 0.000000 )<br>
( -0.000000 0.000000 0.459821 0.000000 0.000000 0.000000 )<br>
( -0.000000 0.000000 0.587885 0.000000 0.000000 0.000000 )<br>
( -0.000000 0.000000 0.198972 0.000000 0.000000 0.000000 )<br>
( -0.000000 0.000000 0.196780 0.000000 0.000000 0.000000 )<br>
( -0.000000 0.000000 0.329227 0.000000 0.000000 0.000000 )<br>
freq ( 2) = -1.060822 [THz] = -35.385228 [cm-1]<br>
( -0.000000 0.000000 0.000000 0.000000 -0.414150 0.000000 )<br>
( -0.000000 0.000000 0.000000 0.000000 -0.439225 0.000000 )<br>
( -0.000000 0.000000 0.000000 0.000000 -0.056206 0.000000 )<br>
( -0.000000 0.000000 0.000000 0.000000 -0.062366 0.000000 )<br>
( -0.000000 0.000000 0.000000 0.000000 -0.117122 0.000000 )<br>
( -0.000000 0.000000 0.000000 0.000000 -0.133873 0.000000 )<br>
( -0.000000 0.000000 0.000000 0.000000 -0.562859 0.000000 )<br>
( -0.000000 0.000000 0.000000 0.000000 -0.529209 0.000000 )<br>
freq ( 3) = -0.654067 [THz] = -21.817316 [cm-1]<br>
( 0.587250 0.000000 0.000000 0.000000 -0.000000 0.000000 )<br>
( 0.225304 0.000000 0.000000 0.000000 -0.000000 0.000000 )<br>
( 0.109064 0.000000 0.000000 0.000000 0.000000 0.000000 )<br>
( 0.136911 0.000000 0.000000 0.000000 -0.000000 0.000000 )<br>
( 0.074583 0.000000 0.000000 0.000000 -0.000000 0.000000 )<br>
( 0.058109 0.000000 0.000000 0.000000 -0.000000 0.000000 )<br>
( 0.252114 0.000000 0.000000 0.000000 -0.000000 0.000000 )<br>
( 0.707980 0.000000 0.000000 0.000000 -0.000000 0.000000 )<br>
</span>
</p>
<div style="white-space:nowrap;">
<br>
</div>
...
<p>
<br>
</p>
<p>
<span style="font-family:'Microsoft YaHei';">'''<br>
</span>
</p>
<p>
<span style="font-family:'Microsoft YaHei';"><span style="font-family:"Microsoft YaHei";text-wrap:wrap;">when the q mesh is 2*1*2</span></span>
</p>
<p>
<span style="font-family:'Microsoft YaHei';">'''</span>
</p>
<p>
<span style="font-family:'Microsoft YaHei';">&INPUTPH<br>
outdir = './'<br>
prefix = 'LaTe3'<br>
fildvscf = 'dvscf'<br>
tr2_ph = 1.0d-14<br>
!nmix_ph = 4<br>
alpha_mix(1) = 0.1<br>
fildyn = 'LaTe3.dyn'<br>
ldisp = .true.<br>
nq1 = 2, nq2 = 1, nq3 = 2<br>
/<br>
</span>
</p>
<div>
<br>
</div>
'''<br>
<p>
<br>
</p>
<p>
<span style="font-family:"Microsoft YaHei";text-wrap:wrap;">I got the same result at gamma point.</span>
</p>
<p>
<span style="font-family:'Microsoft YaHei';">'''</span>
</p>
<p>
<span style="font-family:'Microsoft YaHei';"> q = ( 0.000000000 0.000000000 0.000000000 )<br>
<br>
**************************************************************************<br>
freq ( 1) = -1.302759 [THz] = -43.455374 [cm-1]<br>
( -0.000000 0.000000 0.422782 0.000000 0.000000 0.000000 )<br>
( 0.000000 0.000000 0.247942 0.000000 0.000000 0.000000 )<br>
( -0.000000 0.000000 0.126621 0.000000 0.000000 0.000000 )<br>
( -0.000000 0.000000 0.459821 0.000000 0.000000 0.000000 )<br>
( -0.000000 0.000000 0.587885 0.000000 0.000000 0.000000 )<br>
( -0.000000 0.000000 0.198972 0.000000 0.000000 0.000000 )<br>
( -0.000000 0.000000 0.196780 0.000000 0.000000 0.000000 )<br>
( -0.000000 0.000000 0.329227 0.000000 0.000000 0.000000 )<br>
freq ( 2) = -1.060822 [THz] = -35.385228 [cm-1]<br>
( -0.000000 0.000000 0.000000 0.000000 -0.414150 0.000000 )<br>
( -0.000000 0.000000 0.000000 0.000000 -0.439225 0.000000 )<br>
( -0.000000 0.000000 0.000000 0.000000 -0.056206 0.000000 )<br>
( -0.000000 0.000000 0.000000 0.000000 -0.062366 0.000000 )<br>
( -0.000000 0.000000 0.000000 0.000000 -0.117122 0.000000 )<br>
( -0.000000 0.000000 0.000000 0.000000 -0.133873 0.000000 )<br>
( -0.000000 0.000000 0.000000 0.000000 -0.562859 0.000000 )<br>
( -0.000000 0.000000 0.000000 0.000000 -0.529209 0.000000 )<br>
freq ( 3) = -0.654067 [THz] = -21.817316 [cm-1]<br>
( 0.587250 0.000000 0.000000 0.000000 -0.000000 0.000000 )<br>
( 0.225304 0.000000 0.000000 0.000000 -0.000000 0.000000 )<br>
( 0.109064 0.000000 0.000000 0.000000 0.000000 0.000000 )<br>
( 0.136911 0.000000 0.000000 0.000000 -0.000000 0.000000 )<br>
( 0.074583 0.000000 0.000000 0.000000 -0.000000 0.000000 )<br>
( 0.058109 0.000000 0.000000 0.000000 -0.000000 0.000000 )<br>
( 0.252114 0.000000 0.000000 0.000000 -0.000000 0.000000 )<br>
( 0.707980 0.000000 0.000000 0.000000 -0.000000 0.000000 )<br>
...</span>
</p>
<p>
<span style="font-family:'Microsoft YaHei';">'''</span>
</p>
<p>
<span style="font-family:'Microsoft YaHei';">However, when the q mesh is 3*1*3 <br>
</span>
</p>
<p>
<span style="font-family:'Microsoft YaHei';">'''</span>
</p>
<p>
<span style="font-family:'Microsoft YaHei';">&INPUTPH<br>
outdir = './'<br>
prefix = 'LaTe3'<br>
fildvscf = 'dvscf'<br>
tr2_ph = 1.0d-14<br>
!nmix_ph = 4<br>
alpha_mix(1) = 0.1<br>
fildyn = 'LaTe3.dyn'<br>
ldisp = .true.<br>
nq1 = 3, nq2 = 1, nq3 = 3<br>
/</span>
</p>
<p>
<span style="font-family:'Microsoft YaHei';">I got totally different result.</span>
</p>
<p>
<span style="font-family:'Microsoft YaHei';">'''</span>
</p>
<p>
<span style="font-family:'Microsoft YaHei';"> q = ( 0.000000000 0.000000000 0.000000000 )<br>
<br>
**************************************************************************<br>
freq ( 1) = -1.409025 [THz] = -47.000003 [cm-1]<br>
( 0.000000 0.000000 -0.000000 0.000000 0.403240 0.000000 )<br>
( 0.000000 0.000000 0.000000 0.000000 0.321082 0.000000 )<br>
( 0.000000 0.000000 0.000000 0.000000 0.268880 0.000000 )<br>
( 0.000000 0.000000 -0.000000 0.000000 0.320026 0.000000 )<br>
( 0.000000 0.000000 -0.000000 0.000000 0.327754 0.000000 )<br>
( 0.000000 0.000000 0.000000 0.000000 0.273376 0.000000 )<br>
( 0.000000 0.000000 -0.000000 0.000000 0.385441 0.000000 )<br>
( 0.000000 0.000000 -0.000000 0.000000 0.478403 0.000000 )<br>
freq ( 2) = -1.153248 [THz] = -38.468209 [cm-1]<br>
( -0.000000 0.000000 -0.000000 0.000000 0.287374 0.000000 )<br>
( -0.000000 0.000000 -0.000000 0.000000 -0.363566 0.000000 )<br>
( -0.000000 0.000000 -0.000000 0.000000 -0.389836 0.000000 )<br>
( -0.000000 0.000000 -0.000000 0.000000 0.357680 0.000000 )<br>
( -0.000000 0.000000 -0.000000 0.000000 0.347074 0.000000 )<br>
( -0.000000 0.000000 -0.000000 0.000000 -0.378566 0.000000 )<br>
( -0.000000 0.000000 -0.000000 0.000000 -0.401350 0.000000 )<br>
( -0.000000 0.000000 -0.000000 0.000000 0.283682 0.000000 )<br>
freq ( 3) = -1.000683 [THz] = -33.379207 [cm-1]<br>
( 0.417877 0.000000 -0.000000 0.000000 0.000000 0.000000 )<br>
( 0.441944 0.000000 -0.000000 0.000000 -0.000000 0.000000 )<br>
( 0.063983 0.000000 -0.000000 0.000000 -0.000000 0.000000 )<br>
( 0.108088 0.000000 -0.000000 0.000000 0.000000 0.000000 )<br>
( 0.138847 0.000000 -0.000000 0.000000 0.000000 0.000000 )<br>
( 0.093913 0.000000 -0.000000 0.000000 -0.000000 0.000000 )<br>
( 0.563966 0.000000 -0.000000 0.000000 -0.000000 0.000000 )<br>
( 0.517814 0.000000 -0.000000 0.000000 0.000000 0.000000 )<br>
</span>
</p>
<div style="white-space:nowrap;">
<br>
</div>
...
<p>
<br>
</p>
<p>
<span style="font-family:'Microsoft YaHei';">'''</span>
</p>
<p>
<span style="font-family:'Microsoft YaHei';">This makes me very confused. Could you please tell me the reason for this?</span><span style="font-family:'Microsoft YaHei';"></span><span style="font-family:"Microsoft YaHei";"></span><span style="font-family:'Microsoft YaHei';"><br>
</span><span style="font-family:'Microsoft YaHei';">Looking forward to your reply.<br>
</span>
</p>
<p>
<span style="font-family:'Microsoft YaHei';">Yours, Zihao</span>
</p>