[QE-users] Are there any problems with my DOS results?

José Xavier jxln_karate at yahoo.com.br
Sun Dec 5 18:29:03 CET 2021


Dear QE users,

I'm new in QE. I'm trying to reproduce a paper published previously by the group I'm working with. 
I followed the Hands-on steps to create my input files and graphs. I performed vc-relax, SCF, NSCF, and DOS calculations (the files of the last three calculations are in the same folder and using the same outdir). However, I'm having a "problem" with my DOS results.

My SCF HOMO is 1.0535

My NSCF/DOS EFermi is 2.619

When I use the SCF HOMO value to adjust the column of the DOS table (within Gnuplot) the last (negative energy) peak is finishing close to 0 eV and the next peak (positive energy) is starting close to 5 eV, very similar to the behavior shown by the paper. On the other hand, by using the EFermi, as I saw in the Hands-on and other tutorials, Gnuplot pulls all the peaks more than 1 eV "behind". I know that the gap energy continues the same, but I thought the value that I should use to set the Gnuplot correctly was EFermi. Could someone, please, help me to understand what I'm doing wrong?

I put the SCF file below since the other calculations have similar parameters (in the NSCF the occupations was set to tetrahedra_opt and the k-points to 4 4 4):

*OBS: pseudopotentials were obtained from PseudoDojo (ONCVPSP 0.4.1 - stringent - PBE)

&control
title = 'aa',
restart_mode = 'from_scratch',
prefix = 'aa',
pseudo_dir = '.',
outdir = './outdir',
calculation = 'scf',
nstep = 1500,
etot_conv_thr = 5.0D-7,
forc_conv_thr = 1.0D-4,
verbosity = 'high',
/

&system
ibrav = 8,
a = 13.48431,
b = 7.48432,
c = 5.07832,
nat = 68,
ntyp = 4,
ecutwfc = 74,
ecutrho = 296,
input_dft = 'PBE',
vdw_corr = 'ts',
/

&electrons
electron_maxstep = 500,
mixing_beta = 0.5,
conv_thr = 1.0D-8,
/

&ions
/

&cell
/

ATOMIC_SPECIES
C     12.011000 C.upf
N     14.006700 N.upf
O     15.999400 O.upf
H      1.007900 H.upf


ATOMIC_POSITIONS (angstrom)
C             6.7449840880        1.2295048000        1.4832979096
C             5.3836784505        0.7179029366        1.9734407697
C             4.3225897212        1.8236813423        2.1137402242
C             3.9422727104        2.4608767688        0.7862183004
N             5.5353423132        0.0059389647        3.2735492416
O             7.6145484830        1.4477294077        2.3660616239
O             6.8733033993        1.4021772236        0.2352091076
O             3.2047834103        1.1541668555        2.6999923363
H             6.1287791971        0.5377833550        3.9558647363
H             4.6102669199       -0.1397683790        3.7128803803
H             5.9467458267       -0.9407096629        3.0868675914
H             4.9931768059       -0.0106394517        1.2595940057
H             4.7029369169        2.5973939680        2.8076767846
H             2.4106598932        1.7586880696        2.7917594682
H             3.0778149260        3.1175662601        0.9382242088
H             4.7576167541        3.0624207774        0.3731037113
H             3.6572162710        1.6992079877        0.0509592216
C            -0.0028311376        6.2548189246        4.0224609045
C             1.3584744999        6.7664207880        4.5126037645
C             2.4195632293        5.6606423824        4.6529032190
C             2.7998802400        5.0234469558        3.3253812953
N             1.2068106372        7.4783847599        5.8127122365
O            -0.8723955326        6.0365943169        4.9052246187
O            -0.1311504489        6.0821465011        2.7743721024
O             3.5373695401        6.3301568692        5.2391553312
H             0.6133737533        6.9465403696        6.4950277312
H             2.1318860305        7.6240921036        6.2520433752
H             0.7954071237        8.4250333875        5.6260305862
H             1.7489761445        7.4949631763        3.7987570005
H             2.0392160335        4.8869297567        5.3468397794
H             4.3314930572        5.7256356550        5.3309224630
H             3.6643380244        4.3667574645        3.4773872036
H             1.9845361963        4.4219029473        2.9122667062
H             3.0849366794        5.7851157370        2.5901222164
C            13.4871370384        2.5126570623        3.5950280801
C            12.1258314009        3.0242589257        3.1048852200
C            11.0647426716        1.9184805201        2.9645857655
C            10.6844256608        1.2812850935        4.2921076892
N            12.2774952636        3.7362228976        1.8047767481
O            14.3567014335        2.2944324546        2.7122643658
O            13.6154563497        2.3399846387        4.8431168821
O             9.9469363608        2.5879950069        2.3783336534
H            12.8709321475        3.2043785073        1.1224612533
H            11.3524198703        3.8819302413        1.3654456094
H            12.6888987771        4.6828715252        1.9914583983
H            11.7353297563        3.7528013140        3.8187319840
H            11.4450898673        1.1447678944        2.2706492051
H             9.1528128436        1.9834737927        2.2865665215
H             9.8199678764        0.6245956022        4.1401017809
H            11.4997697045        0.6797410850        4.7052222784
H            10.3993692214        2.0429538746        5.0273667681
C             6.7393218128        4.9716666623        1.0558650852
C             8.1006274503        4.4600647989        0.5657222252
C             9.1617161797        5.5658432046        0.4254227707
C             9.5420331904        6.2030386312        1.7529446944
N             7.9489635876        3.7481008270       -0.7343862468
O             5.8697574178        5.1898912701        0.1731013710
O             6.6110025015        5.1443390859        2.3039538872
O            10.2795224905        4.8963287178       -0.1608293415
H             7.3555267037        4.2799452173       -1.4167017415
H             8.8740389809        3.6023934834       -1.1737173855
H             7.5375600742        2.8014521995       -0.5477045965
H             8.4911290949        3.7315224106        1.2795689892
H             8.7813689839        6.3395558303       -0.2685137897
H            11.0736460076        5.5008499319       -0.2525964733
H            10.4064909748        6.8597281225        1.6009387861
H             8.7266891467        6.8045826397        2.1660592835
H             9.8270896298        5.4413698500        2.4882037733


K_POINTS (automatic)
 2 2 2 0 0 0

Thank you for your help

Sincerely, 
José Xavier
Department of Biophysics and Pharmacology
Federal University of Rio Grande do Norte
Natal, Brazil



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