[Pw_forum] High adsorption energies: CO on Ni-111
Elliot Menkah
elliotsmenkah at yahoo.com
Sun Dec 13 19:31:21 CET 2015
Hello Everyone,
In trying to validate the computational methods and configuration of my
system for a desired study, the adsorption energies I obtained upon
computation seems to be about twice the value of what i was expecting.
This is adsorption of CO on nickel surface sites on Ni-111 surface
structure.
Literature mentions the adsorption energies on the sites top, bridge,
fcc and hcp to be: -137.9, -159.0, -163.7 and -164.6 kJ/mol
respectively, whereas i'm getting -305.03, -328.04, -339.56 and -409.55
kJ/mol respectively.
The qualitative trend seems to exists where the hcp site is the most
energetically favourable site for adsorption in both literature and my
study, however, quantitatively, my values are too larger.
I adsorb the molecule on only one side of the slab.
Do I have to adsorb on both sides of the slab in mirror positions to
handle dipole moment perpendicular to the surface due to adsorption?
What could the reason or problem be?
Please find attached the input files of my hcp site calculation for your
perusal.
Thank you.
Kind Regards,
Elliot
--
Elliot S. Menkah, AMRSC
Research Student - Computational Chemistry/ Computational Material Science
Theoretical and Computational Chemistry
Dept. of Chemistry
Kwame Nkrumah UNiversity of Sci. and Tech.
Kumasi
Ghana
Tel: +233 243-055-717
Alt Email: esmenkah at knust.edu.gh
elliotsmenkah at gmail.com
elliotsmenkah at hotmail.com
-------------- next part --------------
&CONTROL
title = 'Ni-2x2-111-6L-MD-CO-3fold-fcc' ,
calculation = 'relax' ,
restart_mode = 'from_scratch' ,
outdir = './tmp' ,
pseudo_dir = '/home/eliot/pseudo' ,
prefix = 'ni-111-2x2-6L-MD-CO-3fold-fcc',
tstress = .true. ,
tprnfor = .true. ,
/
&SYSTEM
ibrav = 0,
celldm(1) = 1.88972599,
nat = 98,
ntyp = 3,
ecutwfc = 40,
ecutrho = 480,
occupations='smearing',
smearing='mp',
degauss=0.05,
nbnd=560,
nspin=2,
starting_magnetization(1)=0.5,
/
&ELECTRONS
conv_thr = 1.0D-6,
mixing_mode = 'local-TF'
/
&IONS
/
ATOMIC_SPECIES
Ni 58.6934 Ni.pbe-nd-rrkjus.UPF
C 12.011 C.pbe-rrkjus.UPF
O 15.999 O.pbe-rrkjus.UPF
ATOMIC_POSITIONS (alat)
Ni 1.245247692 0.718944090 0.015868783 0 0 0
Ni 2.490495415 2.875776414 0.015868783 0 0 0
Ni 3.735743138 0.718944090 0.015868783 0 0 0
Ni 4.980990830 2.875776397 0.015868355 0 0 0
Ni 1.245247472 3.594720360 2.023998778 0 0 0
Ni 2.490495415 5.751553065 2.023998778 0 0 0
Ni 3.735743358 3.594720360 2.023998778 0 0 0
Ni 4.980990830 5.751552793 2.023999431 0 0 0
Ni 1.245247844 6.470496971 4.059965132 0 0 0
Ni 2.490495415 8.627329032 4.059965132 0 0 0
Ni 3.735742986 6.470496971 4.059965132 0 0 0
Ni 4.980990830 8.627329190 4.059964979 0 0 0
Ni 1.246709841 9.346680057 6.089903308
Ni 2.491049866 11.503272365 6.094695989
Ni 3.736309279 9.347499400 6.091839589
Ni 4.981632933 11.503215624 6.094592854
Ni 1.251397606 12.222515270 8.130528230
Ni 2.493872076 14.374876735 8.130574795
Ni 3.736773669 12.222408715 8.121452049
Ni 4.979701257 14.375516889 8.129406603
Ni 1.243830060 15.097651794 10.124780901
Ni 2.490567863 17.254288878 10.125834084
Ni 3.737277529 15.124361083 10.124533866
Ni 4.983701851 17.254644423 10.125942272
Ni 3.735743107 5.032608685 0.015868783 0 0 0
Ni 4.980990830 7.189441009 0.015868783 0 0 0
Ni 6.226238553 5.032608685 0.015868783 0 0 0
Ni 7.471486245 7.189440992 0.015868355 0 0 0
Ni 3.735742887 7.908384955 2.023998778 0 0 0
Ni 4.980990830 10.065217660 2.023998778 0 0 0
Ni 6.226238773 7.908384955 2.023998778 0 0 0
Ni 7.471486245 10.065217388 2.023999431 0 0 0
Ni 3.735743259 10.784161566 4.059965132 0 0 0
Ni 4.980990830 12.940993627 4.059965132 0 0 0
Ni 6.226238401 10.784161566 4.059965132 0 0 0
Ni 7.471486245 12.940993785 4.059964979 0 0 0
Ni 3.736296794 13.660278999 6.094631584
Ni 4.981840953 15.816305949 6.089805212
Ni 6.225869615 13.659635984 6.091567601
Ni 7.472468264 15.816767005 6.089493887
Ni 3.736896631 16.534686190 8.122356924
Ni 4.983572283 18.693711643 8.122423344
Ni 6.227530794 16.536159378 8.121678221
Ni 7.475062891 18.697174708 8.130314215
Ni 3.737430863 19.413420133 10.125793472
Ni 4.981744277 21.571270847 10.124719443
Ni 6.205422793 19.399131231 10.125043022
Ni 7.471688751 21.569920708 10.195553976
Ni 6.226238522 0.718944090 0.015868783 0 0 0
Ni 7.471486245 2.875776414 0.015868783 0 0 0
Ni 8.716733968 0.718944090 0.015868783 0 0 0
Ni 9.961981660 2.875776397 0.015868355 0 0 0
Ni 6.226238302 3.594720360 2.023998778 0 0 0
Ni 7.471486245 5.751553065 2.023998778 0 0 0
Ni 8.716734188 3.594720360 2.023998778 0 0 0
Ni 9.961981660 5.751552793 2.023999431 0 0 0
Ni 6.226238674 6.470496971 4.059965132 0 0 0
Ni 7.471486245 8.627329032 4.059965132 0 0 0
Ni 8.716733816 6.470496971 4.059965132 0 0 0
Ni 9.961981660 8.627329190 4.059964979 0 0 0
Ni 6.225973474 9.346546538 6.089989264
Ni 7.471621945 11.503853546 6.089790972
Ni 8.717377404 9.346452757 6.090683436
Ni 9.963257320 11.503913751 6.089966258
Ni 6.222932962 12.222252478 8.129332507
Ni 7.470857119 14.378343414 8.121361647
Ni 8.718059007 12.222626174 8.121568843
Ni 9.964518686 14.378185126 8.121779387
Ni 6.230847493 15.098640938 10.124112763
Ni 7.474569271 17.253185302 10.124621946
Ni 8.718011778 15.098252280 10.124628469
Ni 9.961558698 17.252773665 10.124595778
Ni 8.716733937 5.032608685 0.015868783 0 0 0
Ni 9.961981660 7.189441009 0.015868783 0 0 0
Ni 11.207229383 5.032608685 0.015868783 0 0 0
Ni 12.452477075 7.189440992 0.015868355 0 0 0
Ni 8.716733717 7.908384955 2.023998778 0 0 0
Ni 9.961981660 10.065217660 2.023998778 0 0 0
Ni 11.207229603 7.908384955 2.023998778 0 0 0
Ni 12.452477075 10.065217388 2.023999431 0 0 0
Ni 8.716734089 10.784161566 4.059965132 0 0 0
Ni 9.961981660 12.940993627 4.059965132 0 0 0
Ni 11.207229231 10.784161566 4.059965132 0 0 0
Ni 12.452477075 12.940993785 4.059964979 0 0 0
Ni 8.717314947 13.660636235 6.089490100
Ni 9.962110380 15.816726745 6.089592695
Ni 11.208740061 13.659631527 6.091948135
Ni 12.452767496 15.816182474 6.090053196
Ni 8.717575346 16.537924157 8.121748080
Ni 9.960512304 18.696990663 8.130311275
Ni 11.207967602 16.535790646 8.121816703
Ni 12.452489216 18.693540783 8.122210426
Ni 8.718626602 19.409894146 10.195007369
Ni 9.966868016 21.570687486 10.192425525
Ni 11.231381306 19.398971630 10.124254459
Ni 12.455857855 21.571478700 10.123984004
C 8.723467559 20.851726334 11.508948792
O 8.727741803 20.853291675 12.699898222
K_POINTS automatic
5 5 1 0 0 0
CELL_PARAMETERS
+9.9619816602 +0.0000000000 +0.0000000000
+4.9809908302 +8.6273291898 +0.0000000000
-0.0000000000 +0.0000000000 +24.2008859472
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