[QE-users] Phonons on Pt(111) electrode

Tom Demeyere T.Demeyere at soton.ac.uk
Thu Jun 23 15:48:23 CEST 2022


Dear users,

I plan to run a phonon calculation on a 3x3x5 Pt(111) slab with a water bilayer network (6 water molecules). I am mostly interested to retrieve thermodynamical properties (ZPE, entropy, …)

I am not an expert in phonon calculations so I tried to gather the maximum knowledge about practicabilities:

	1. I converged my slab with a tight force criteria (5e-5 Ry/Bohr)
        2. I used a (relatively) dense k-point grid (8x8x1)
	3. I used a tight conv_thr (1.0e-12)
        
The pwscf calculation converged fine, now before running the ph.x calculation I want to ensure that I am doing things correctly to not waste a huge amount of CPU time.

	1. I use ldisp = .true. with nq1 = 3, nq2 = 3, nq3 = 1. From what I understand I can use dvscf.q2r.x to extrapolate to a denser q-point grid.
	2. Shoud I use electron-phonon coupling ?

I am still not sure how many q-points I should sample to get accurate properties in this case. You can find the input files below.

If someone has any comments I will be glad to read them.

pw.x:

########################################################################

&CONTROL
  calculation = ‘relax'
  verbosity = 'high'
  pseudo_dir = ‘./PseudoPotentials/'
  etot_conv_thr = 1.0000000000d-06, forc_conv_thr = 1.0000000000d-06
  tprnfor = .true.
  nstep = 200
/
&SYSTEM
  ibrav = 0
  ecutrho = 480, ecutwfc = 60
  nat = 63, ntyp = 3
  occupations = 'smearing', smearing = 'cold', degauss = 0.01
  assume_isolated = "esm", esm_bc = "bc1"
/
&ELECTRONS
  conv_thr = 1.00d-12
  mixing_mode = "local-TF", mixing_beta = 0.9
  electron_maxstep = 500
/
&IONS
  ion_dynamics = "bfgs"
/
ATOMIC_SPECIES
Pt 195.084 pt_pbe_v1.4.uspp.F.UPF
O 15.999 O.pbe-n-kjpaw_psl.0.1.UPF
H 1.008 H.pbe-rrkjus_psl.1.0.0.UPF
ATOMIC_POSITIONS angstrom
Pt            2.5373217835        2.0295229047       -4.5888968330
Pt           -0.2738218732        2.0295388957       -4.5894233272
Pt            5.3365799834        2.0353568119       -4.5795252896
Pt            1.1318086416        4.4638363948       -4.5889405606
Pt            3.9353390422        4.4596042453       -4.5706646360
Pt            6.7376249097        4.4595659277       -4.5717902218
Pt            2.5363313063        6.8849696049       -4.5788980743
Pt            5.3362055829        6.8863768130       -4.5728150076
Pt            8.1364271948        6.8847880311       -4.5778984171
Pt           -0.2710356668        0.4110901595       -2.2635160021
Pt            2.5304095876        0.4117127573       -2.2643675543
Pt            5.3347083478        0.4119432549       -2.2741836554
Pt            1.1294048350        2.8400451188       -2.2930587860
Pt            3.9326847243        2.8397687859       -2.2627650867
Pt            6.7361797317        2.8400461440       -2.2648687096
Pt            2.5320955090        5.2665415032       -2.2629762844
Pt            5.3344344295        5.2672923383       -2.2457844235
Pt            8.1369859259        5.2664747970       -2.2624379737
Pt            1.1281916264        1.2126681677       -0.0096635292
Pt            3.9345031191        1.2178292707       -0.0075273929
Pt            6.7304799442        1.2181779167       -0.0086495243
Pt            2.5349633533        3.6509661719       -0.0056167200
Pt            5.3332494442        3.6526942205        0.0265795854
Pt            8.1286284999        3.6513190427       -0.0061776475
Pt            3.9358756211        6.0708127904        0.0291995120
Pt            6.7277127724        6.0727489195        0.0263478918
Pt            9.5385069383        6.0775166955       -0.0084549988
Pt           -0.2740111230        2.0278230531        2.2396325934
Pt            2.5227988401        2.0284031312        2.2416722095
Pt            5.3283218128        2.0248697346        2.2650789633
Pt            1.1231180565        4.4524680700        2.2462043365
Pt            3.9393724478        4.4613652006        2.3244466806
Pt            6.7169406732        4.4650037326        2.3229828585
Pt            2.5228714086        6.8832243298        2.2647493754
Pt            5.3272210051        6.8688850268        2.3223865859
Pt            8.1360992124        6.8821379852        2.2607778756
Pt           -0.2967578796        0.4255557445        4.5731579608
Pt            2.5362662606        0.4270552168        4.5649584454
Pt            5.3230127653        0.4072766591        4.5914291894
Pt            1.1183594714        2.8343856088        4.5747879958
Pt            3.9083062228        2.8166107271        4.5739577039
Pt            6.7401749755        2.8138898517        4.5652299321
Pt            2.4939195134        5.2643831956        4.5780334412
Pt            5.3198188015        5.2606736712        4.7307508190
Pt            8.1460272356        5.2635932642        4.5778732056
O             1.6641808833        5.2692114097        7.9609963643
H             1.6032927780        5.2684809298        6.9764858291
H             2.6245839593        5.2721214382        8.1286435026
O             1.9109893926        0.3812330303        7.8065282415
H             1.9671779081        0.7842817252        6.9091050994
H             2.8620040989        0.4208560411        8.1454404750
O             5.2202058650        5.2640950072        6.9080163569
H             5.6508249978        4.4331611768        7.2928122500
H             5.6509315720        6.0954385989        7.2912964886
O             4.4518702547        0.4901369883        8.6578035404
H             5.0056580423       -0.2976159487        8.4658999298
H             5.0091448820        1.2787946726        8.4821896051
O             6.1207507950        2.8683082285        7.8074940724
H             6.1833000004        2.4645961699        6.9107200776
H             7.0704653087        2.8326519319        8.1507992552
O             0.2492445926        2.7670426236        8.6676127827
H             0.8047856136        1.9778375785        8.4891125422
H             0.8025047375        3.5545553695        8.4729537518
K_POINTS automatic
8 8 1 0 0 0
CELL_PARAMETERS angstrom
8.409541279253872  0.000000000000000   0.000000000000000
4.204770639626936  7.282876382007739   0.000000000000000
0.000000000000000  0.000000000000000  40.000000000000000

########################################################################

ph.x:

########################################################################

&INPUTPH
  prefix = 'pwscf'
  outdir = '.'
  amass(1) = 195.084
  amass(2) = 15.999
  amass(3) = 1.008
  fildyn = 'matdyn'
  trans = .true.
  ldisp = .true.
  reduce_io = .true.
  nq1 = 3, nq2 = 3, nq3 = 1
/

########################################################################

-----------------------------------------
Tom Demeyere MSc
PhD student
Skylaris Research Group
School of Chemistry, University of Southampton



More information about the users mailing list