[QE-users] Strange frequencies hard to interpret
Jibiao Li
jibiaoli at foxmail.com
Sun Oct 6 13:35:36 CEST 2019
Dear QE experts,
I am studying mixed H2O/OH phase on close packed metal surfaces using QE 6.4.1. To my suprise, however, the calculated vibrational frequencies for the adsorbates are substantially different for the mixed H2O/OH phase on Ag(111) and Au(111)
For the latter (on Au(111)), I obtained
freq ( 46 - 46) = 48.0 [cm-1] --> A I+R
freq ( 47 - 47) = 120.8 [cm-1] --> A I+R
freq ( 48 - 48) = 145.1 [cm-1] --> A I+R
freq ( 49 - 49) = 197.5 [cm-1] --> A I+R
freq ( 50 - 50) = 280.7 [cm-1] --> A I+R
freq ( 51 - 51) = 369.2 [cm-1] --> A I+R
freq ( 52 - 52) = 575.0 [cm-1] --> A I+R
freq ( 53 - 53) = 869.7 [cm-1] --> A I+R
freq ( 54 - 54) = 873.8 [cm-1] --> A I+R
freq ( 55 - 55) = 926.4 [cm-1] --> A I+R
freq ( 56 - 56) = 1011.7 [cm-1] --> A I+R
freq ( 57 - 57) = 1537.5 [cm-1] --> A I+R
freq ( 58 - 58) = 3025.7 [cm-1] --> A I+R
freq ( 59 - 59) = 3055.8 [cm-1] --> A I+R
freq ( 60 - 60) = 3566.1 [cm-1] --> A I+R
Obviously, one OH stretching frequency of the adsorbed water is missing. Does anybody know why is this ?
For the former (on Ag(111)), I got
freq ( 46 - 46) = 47.8 [cm-1] --> A I+R
freq ( 47 - 47) = 49.8 [cm-1] --> A I+R
freq ( 48 - 48) = 54.3 [cm-1] --> A I+R
freq ( 49 - 49) = 80.1 [cm-1] --> A I+R
freq ( 50 - 50) = 84.7 [cm-1] --> A I+R
freq ( 51 - 51) = 99.0 [cm-1] --> A I+R
freq ( 52 - 52) = 111.2 [cm-1] --> A I+R
freq ( 53 - 53) = 117.9 [cm-1] --> A I+R
freq ( 54 - 54) = 187.9 [cm-1] --> A I+R
freq ( 55 - 55) = 849.4 [cm-1] --> A I+R
freq ( 56 - 56) = 1005.9 [cm-1] --> A I+R
freq ( 57 - 57) = 1572.9 [cm-1] --> A I+R
freq ( 58 - 58) = 2824.8 [cm-1] --> A I+R
freq ( 59 - 59) = 3670.5 [cm-1] --> A I+R
freq ( 60 - 60) = 3782.1 [cm-1] --> A I+R
Why the two surfaces differ so much regarding the adsrobate frequencies ?
Ag111.SCF input
&CONTROL
calculation = 'scf' ,
restart_mode = 'from_scratch' ,
outdir = './' ,
pseudo_dir = '/home/jibiaoli/pseudo/' ,
prefix = 'sym' ,
tstress = .true. ,
tprnfor = .true. ,
/
&SYSTEM
ibrav = 0,
celldm(1) = 9.456004324,
nat = 20,
ntyp = 3,
ecutwfc = 49 ,
ecutrho = 411 ,
occupations = 'smearing' ,
degauss = 0.02 ,
smearing = 'methfessel-paxton' ,
vdw_corr = 'DFT-D',
/
&ELECTRONS
mixing_beta = 0.3 ,
diagonalization = 'david' ,
/
CELL_PARAMETERS alat
0.866025404 0.500000000 0.000000000
0.866025404 -0.500000000 0.000000000
0.000000000 0.000000000 5.400000000
ATOMIC_SPECIES
Ag 107.8682 Ag.pbe-n-kjpaw_psl.1.0.0.UPF
O 15.99940 O.pbe-n-kjpaw_psl.1.0.0.UPF
H 1.00800 H.pbe-kjpaw_psl.1.0.0.UPF
ATOMIC_POSITIONS angstrom
O 5.986597700 0.051902808 11.800640138
H 6.530086903 0.896034963 11.935550794
H 6.519207423 -0.788895855 11.940829013
O 2.800029893 0.013830142 11.748050047
H 3.756125095 0.022425916 11.956803063
Ag -0.454154628 0.136836718 9.568098196
Ag 5.307442766 0.123896111 9.577760992
Ag 2.445911493 0.129358587 9.587754292
Ag 2.920157088 1.499919274 7.139192063
Ag 1.485120252 -0.981971793 7.160426239
Ag 4.380244685 -0.987689704 7.134282475
Ag 2.889028971 -1.667975200 4.717759990 0 0 0
Ag 4.333537867 0.833997281 4.717759990 0 0 0
Ag 5.778055146 -1.667970358 4.717759990 0 0 0
Ag 0.000000000 0.000000000 2.358879995 0 0 0
Ag 5.778052352 0.000009682 2.358879995 0 0 0
Ag 2.889026176 0.000004841 2.358879995 0 0 0
Ag 2.889023381 1.667984881 0.000000000 0 0 0
Ag 1.444514485 -0.833987600 0.000000000 0 0 0
Ag 4.333540661 -0.833982759 0.000000000 0 0 0
K_POINTS automatic
4 4 1 0 0 0
phonons at Gamma
&inputph
tr2_ph=1.0d-14,
prefix='sym',
alpha_mix=0.1,
fildyn='phG.dyn',
amass(3)=107.8682,
amass(1)=15.999,
amass(2)=1.0079,
outdir='./'
nat_todo=5,
/
0.0 0.0 0.0
1 2 3 4 5
Au111.SCF input
&CONTROL
calculation = 'scf' ,
restart_mode = 'from_scratch' ,
outdir = './' ,
pseudo_dir = '/home/jibiaoli/pseudo/' ,
prefix = 'sym' ,
tstress = .true. ,
tprnfor = .true. ,
/
&SYSTEM
ibrav = 0,
celldm(1) = 9.438996782,
nat = 20,
ntyp = 3,
ecutwfc = 49 ,
ecutrho = 411 ,
occupations = 'smearing' ,
degauss = 0.02 ,
smearing = 'methfessel-paxton' ,
vdw_corr = 'DFT-D',
/
&ELECTRONS
mixing_beta = 0.3 ,
diagonalization = 'david' ,
/
CELL_PARAMETERS alat
0.866025404 0.500000000 0.000000000
0.866025404 -0.500000000 0.000000000
0.000000000 0.000000000 5.400000000
ATOMIC_SPECIES
Au 196.966 Au.pbe-n-kjpaw_psl.1.0.0.UPF
O 15.99940 O.pbe-n-kjpaw_psl.1.0.0.UPF
H 1.00800 H.pbe-kjpaw_psl.1.0.0.UPF
ATOMIC_POSITIONS angstrom
O 5.912480742 0.009178221 11.632181430
H 6.464419524 0.843711872 11.746544250
H 6.463965595 -0.824906263 11.746208129
O 2.776101640 0.006280334 11.529141825
H 3.735828757 0.004486229 11.732591760
Au -0.212193475 0.013514349 9.300103694
Au 5.522293374 0.005423066 9.291997619
Au 2.653858209 0.011159754 9.350961280
Au 2.820570847 1.652453082 6.986020697
Au 1.396774134 -0.827316157 6.994544598
Au 4.265011175 -0.828154887 6.977373986
Au 2.883796376 -1.664954171 4.709215206 0 0 0
Au 4.325688984 0.832486750 4.709215206 0 0 0
Au 5.767589961 -1.664949338 4.709215206 0 0 0
Au 0.000000000 0.000000000 2.354607603 0 0 0
Au 5.767587172 0.000009664 2.354607603 0 0 0
Au 2.883793585 0.000004832 2.354607603 0 0 0
Au 2.883790796 1.664963835 0.000000000 0 0 0
Au 1.441898188 -0.832477085 0.000000000 0 0 0
Au 4.325691773 -0.832472253 0.000000000 0 0 0
K_POINTS automatic
4 4 1 0 0 0
phonons at Gamma
&inputph
tr2_ph=1.0d-14,
prefix='sym',
alpha_mix=0.1,
fildyn='phG.dyn',
amass(1)=196.966,
amass(2)=15.999,
amass(3)=1.0079,
outdir='./'
nat_todo=5,
/
0.0 0.0 0.0
1 2 3 4 5
------------------
Dr. Jibiao Li,
Department of Material Science and Engineering
Yangtze Normal University
Juxian Dadao 16#, Fuling, Chongqing, China
Email: jibiaoli at yznu.edu.cn, jibiaoli at foxmail.com, jibiao.li at hotmail.com
Homepage: https://www.researchgate.net/profile/Jibiao_Li
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