<div dir="ltr">Dear all,<div><br></div><div>I was doing phonon dispersion calculations for lithium iron phosphate. However, the calculation speed is really slow and it does not converge. Is this because my system is too big? There are 28 atoms in the unit cell. My input file is like this:</div><div>(1)</div><div><br></div><div><p style="margin:0px;font-family:Menlo">&CONTROL</p>
<p style="margin:0px;font-family:Menlo">calculation = "scf",</p>
<p style="margin:0px;font-family:Menlo">pseudo_dir = "/home/xiaolin/pseudo",</p>
<p style="margin:0px;font-family:Menlo">outdir = "/home/xiaolin/test2",</p>
<p style="margin:0px;font-family:Menlo">tstress=.true.,</p>
<p style="margin:0px;font-family:Menlo">tprnfor=.true.,</p>
<p style="margin:0px;font-family:Menlo">nstep=100,</p>
<p style="margin:0px;font-family:Menlo">/</p>
<p style="margin:0px;font-family:Menlo">&SYSTEM</p>
<p style="margin:0px;font-family:Menlo">ibrav = 8,</p>
<p style="margin:0px;font-family:Menlo">celldm(1) = 19.749526</p>
<p style="margin:0px;font-family:Menlo">celldm(2) = 0.582432,</p>
<p style="margin:0px;font-family:Menlo">celldm(3) = 0.454693,</p>
<p style="margin:0px;font-family:Menlo">nat = 28,</p>
<p style="margin:0px;font-family:Menlo">ntyp = 4,</p>
<p style="margin:0px;font-family:Menlo">ecutwfc = 80.D0,</p>
<p style="margin:0px;font-family:Menlo">/</p>
<p style="margin:0px;font-family:Menlo">&ELECTRONS</p>
<p style="margin:0px;font-family:Menlo">mixing_beta = 0.7,</p>
<p style="margin:0px;font-family:Menlo">/</p>
<p style="margin:0px;font-family:Menlo">&IONS</p>
<p style="margin:0px;font-family:Menlo">/</p>
<p style="margin:0px;font-family:Menlo">ATOMIC_SPECIES</p><p style="margin:0px;font-family:Menlo">Li 6.941 Li.pbe-s-hgh.UPF</p><p style="margin:0px;font-family:Menlo">Fe 55.845 Fe.pbe-sp-hgh.UPF</p><p style="margin:0px;font-family:Menlo">P 30.97376 P.pbe-hgh.UPF</p><p style="margin:0px;font-family:Menlo">O 15.9994 O.pbe-hgh.UPF</p><p style="margin:0px;font-family:Menlo">ATOMIC_POSITIONS (alat)</p><p style="margin:0px;font-family:Menlo">Li 0 0 0</p><p style="margin:0px;font-family:Menlo">...</p><p style="margin:0px;font-family:Menlo">K_POINTS (automatic)</p><p style="margin:0px;font-family:Menlo">
</p><p style="margin:0px;font-family:Menlo">1 1 1 0 0 0</p><p style="margin:0px;font-family:Menlo"><br></p><p style="margin:0px;font-family:Menlo">(2)</p><p style="margin:0px;font-family:Menlo"><br></p><p style="margin:0px;font-family:Menlo">Normal modes for lifepo4</p>
<p style="margin:0px;font-family:Menlo">&inputph</p>
<p style="margin:0px;font-family:Menlo">tr2_ph=1.5d-5,</p>
<p style="margin:0px;font-family:Menlo">amass(1)=6.941,</p>
<p style="margin:0px;font-family:Menlo">amass(2)=55.845,</p>
<p style="margin:0px;font-family:Menlo">amass(3)=30.97376,</p>
<p style="margin:0px;font-family:Menlo">amass(4)=15.9994,</p>
<p style="margin:0px;font-family:Menlo">outdir = '/home/xiaolin/test2',</p>
<p style="margin:0px;font-family:Menlo">trans=.true.,</p>
<p style="margin:0px;font-family:Menlo">asr=.true.,</p>
<p style="margin:0px;font-family:Menlo">nogg=.true.,</p>
<p style="margin:0px;font-family:Menlo">fildyn='dmat.lifepo4'</p>
<p style="margin:0px;font-family:Menlo">/</p>
<p style="margin:0px;font-family:Menlo">0.0 0.0 0.0</p><p style="margin:0px;font-family:Menlo"><br></p><p style="margin:0px;font-family:Menlo"><br></p><p style="margin:0px;font-family:Menlo">Thank you in advance!</p><p style="margin:0px;font-family:Menlo"><br></p><p style="margin:0px;font-family:Menlo">Lin</p></div></div>