Dear Friends-<br><br>Thank you for the previous answers. I have changed my script and the calculation is able to continue. I used matdyn.x to calculate Graphene nanoribbon's phonon dispersion. zasr and asr are both set to be 'simple'. However, the results have some negative frequencies. Attached are my scf and ph calculation inputs. Thank you everyone. I have tried tr2_ph=1.0d-20, but still some of the frequencies are negative.<br>
<br>*********************************************<br> &control<br> calculation='scf'<br> restart_mode='from_scratch',<br> tstress = .true.<br> tprnfor = .true.<br> prefix='GNR7',<br>
pseudo_dir = '/scratch/scratch96/h/huang87/espresso-4.1.1/pseudo/',<br> outdir='/scratch/scratch96/h/huang87/espresso-4.1.1/ZhenCalculation/GNRTry7/'<br> /<br> &system<br> ibrav= 0, celldm(1) =8.04, nat= 8, ntyp= 1, nbnd= 16,<br>
ecutwfc =25.0, ecutrho= 250, occupations='smearing', smearing='marzari-vanderbilt',<br> degauss=0.01<br><br> /<br> &electrons<br> diagonalization='david'<br> conv_thr = 1.0d-8<br>
mixing_beta = 0.3<br> /<br>ATOMIC_SPECIES<br> C 12.0107 C.pz-rrkjus.UPF<br><br>CELL_PARAMETERS<br><br>1.00000000 0.00000000 0.00000000<br>0.00000000 2.00000000 0.00000000<br>0.00000000 0.00000000 2.00000000<br><br>
<br>
ATOMIC_POSITIONS<br><br> C 0.00000 0.0000000 1.00<br> C 0.33333 0.0000000 1.00<br> C 0.00000 0.5773503 1.00<br> C 0.33333 0.5773503 1.00<br> C 0.50000 0.2886751 1.00<br> C 0.83333 0.2886751 1.00<br> C 0.50000 0.8660254 1.00<br>
C 0.83333 0.8660254 1.00<br><br>K_POINTS (automatic)<br> 4 2 2 0 0 0<br><br>**********************************************<br>phonons of GNR<br> &inputph<br> tr2_ph=1.0d-14,<br> prefix='GNR7',<br> ldisp=.true.,<br>
nq1=4, nq2=2, nq3=2<br> amass(1)=12.0107,<br> outdir='/scratch/scratch96/h/huang87/espresso-4.1.1/ZhenCalculation/GNRTry7/',<br> fildyn='GNR7.dyn',<br> /<br>*********************************************<br>
&input<br> fildyn='GNR7.dyn', zasr='simple', flfrc='GNR7422.fc'<br> /<br>**********************************************<br> &input<br> asr='simple', amass(1)=12.0107,<br> flfrc='GNR7422.fc', flfrq='GNR.freq'<br>
/<br>*********************************************<br><br> &plot nbnd= 24, nks= 9 /<br> 0.000000 0.000000 0.000000<br> -0.4610 -0.3111 0.0000 121.7438 367.9945 384.5799<br> 413.7865 484.1542 510.3023 517.1610 525.6054 585.8687<br>
651.6492 720.8406 741.2300 795.1452 885.5967 1130.3063<br> 1218.8189 1246.9269 1269.9958 1303.1663 1339.6477 1554.4453<br> 0.125000 0.000000 0.000000<br> -30.9170 46.6076 130.1963 162.4561 279.5289 367.1598<br>
430.1985 440.0616 510.8467 546.5418 560.7955 628.0727<br> 667.2951 696.7286 731.3699 815.1829 947.5298 1115.9129<br> 1195.5418 1252.4357 1271.0919 1323.5225 1360.0568 1545.7346<br> 0.250000 0.000000 0.000000<br>
-227.7136 20.5742 167.4320 195.2321 241.6912 295.0974<br> 348.1145 375.1411 453.7153 525.8999 589.9650 608.7267<br> 645.8124 648.2918 722.7903 858.2595 1042.6514 1045.2181<br> 1204.0510 1263.8339 1277.5066 1342.1550 1409.9760 1527.4094<br>
0.375000 0.000000 0.000000<br> -791.8930 -664.3496 100.0539 140.1844 145.6394 290.9220<br> 369.3768 385.8012 426.2218 459.6231 536.7560 558.0773<br> 713.5138 721.5818 735.4358 896.6492 984.5893 1077.9200<br>
1225.3378 1256.3345 1311.6804 1352.8788 1457.1024 1510.0736<br><br clear="all">Best Regards<br>-------<br>Zhen (Alex) Huang<br>Ph.D. Student<br>Nanoscale Transport Research Group<br>Laboratory for Computational Methods in Emerging Technologies <br>
Cooling Technologies Research Center<br>School of Mechanical Engineering<br>Purdue University<br>Tel: 765 237 9733<br>