[Pw_forum] Force is fluctuating for water system
Marzari Nicola
nicola.marzari at epfl.ch
Sat Dec 23 14:48:52 CET 2017
Blyp will not work. Read eg prl by scandolo baletto on e- in ice, and the mauri approach for self-interaction corrections in this case.
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On 22 Dec 2017, at 13:33, Narendranath Ghosh <ghosh.naren13 at gmail.com<mailto:ghosh.naren13 at gmail.com>> wrote:
Dear Lorenzo , Dear Seitsonen Thank you very much. Actually what I am trying to find is to Where do the excess e- prefer to stay in my water system ?
I have crossed 50 BFGS steps but still it could not find the minimum.
The Force is fluctuating very much .I have applied 90 Ry with a pseudo potential and used BLYP exchange-correlation functional from a standard reference. (THE JOURNAL OF CHEMICAL PHYSICS 128, 214506 2008)
any other factor that should care relaxing a system with odd number of electrons.
Dr. Narendra Nath Ghosh
Research Associate
University of Gour Banga
Malda-732102
India
Phone No : 09126667601
On Fri, Dec 22, 2017 at 2:07 AM, Ari P Seitsonen <Ari.P.Seitsonen at iki.fi<mailto:Ari.P.Seitsonen at iki.fi>> wrote:
Dear Narendra Nath Ghosh,
Adding to Lorenzo's answer, a small note: You seem to have an odd number of electrons but you do not specify 'nspin = 2' - are you sure that this is what you intended to do (physically)? 70 Ry with a pseudo potential à la Troullier-Martins for oxygen, it might be at the lower limit (it depends on the core radii, usually I would go for 80-90 Ry minimum). And, do you know if the electron gets localised or remains delocalised - this is an open question to my knowledge, and might well depend on the kind of exchange-correlation functional used (GGA like BLYP probably delocalise it - with the highest occupied orbital in the conduction band - and hybrid functionals might localise it).
Greetings from Helsinki/Finland,
apsi
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Ari Paavo Seitsonen / Ari.P.Seitsonen at iki.fi<mailto:Ari.P.Seitsonen at iki.fi> / http://www.iki.fi/~apsi/
Ecole Normale Supérieure (ENS), Département de Chimie, Paris
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On Tue, 19 Dec 2017, Narendranath Ghosh wrote:
Dear all
I am relaxing a system of 128 water molecule with extra electron.The force is fluctuating even after bfgs
steps = 48.
Input:
&CONTROL
calculation='relax',
outdir='/share_home/hpc/NEGATIVE_HYDRATED_ELECTRON/OUTPUT',
prefix='water-128-negative',
pseudo_dir='/share_home/hpc/RESEARCH_SCHOLAR/HYDRATED-ELECTRON/pseudo',
verbosity='high',
restart_mode='restart',
/
&SYSTEM
ibrav=0,
celldm(1)=29.8576727681d0,
nat=384,
tot_charge=-1,
ntyp=2,
ecutwfc=70,
ecutrho=280,
input_dft='BLYP',
occupations='smearing',
degauss=0.05d0,
/
&ELECTRONS
mixing_beta=0.500d0,
electron_maxstep=500,
/
&IONS
/
ATOMIC_SPECIES
O 16.0d0 O.blyp-mt.UPF
H 1.0079d0 H.blyp-vbc.UPF
K_POINTS {automatic}
1 1 1 0 0 0
CELL_PARAMETERS {alat}
1.000000000000d0 0.000000000000d0 0.000000000000d0
0.000000000000d0 1.000000000000d0 0.000000000000d0
0.000000000000d0 0.000000000000d0 1.000000000000d0
Output
Total force = 0.030447 Total SCF correction = 0.001115
Total force = 0.033732 Total SCF correction = 0.000223
Total force = 0.042921 Total SCF correction = 0.000171
Total force = 0.032971 Total SCF correction = 0.000165
Total force = 0.032983 Total SCF correction = 0.000266
Total force = 0.036132 Total SCF correction = 0.000252
Total force = 0.040191 Total SCF correction = 0.000833
Total force = 0.032897 Total SCF correction = 0.001663
Total force = 0.025425 Total SCF correction = 0.000288
Total force = 0.019869 Total SCF correction = 0.000279
Total force = 0.020382 Total SCF correction = 0.000102
Total force = 0.025164 Total SCF correction = 0.000109
Total force = 0.027580 Total SCF correction = 0.000141
Total force = 0.026211 Total SCF correction = 0.000188
Total force = 0.023574 Total SCF correction = 0.000139
Total force = 0.024877 Total SCF correction = 0.000103
Total force = 0.027597 Total SCF correction = 0.000131
Total force = 0.027563 Total SCF correction = 0.000169
Total force = 0.023015 Total SCF correction = 0.000195
Total force = 0.021111 Total SCF correction = 0.000109
Total force = 0.021345 Total SCF correction = 0.000092
Total force = 0.023793 Total SCF correction = 0.000129
Total force = 0.024400 Total SCF correction = 0.000145
Total force = 0.025073 Total SCF correction = 0.000243
Total force = 0.022300 Total SCF correction = 0.000376
Total force = 0.020060 Total SCF correction = 0.000097
Total force = 0.021991 Total SCF correction = 0.000134
Total force = 0.022541 Total SCF correction = 0.000132
Total force = 0.023051 Total SCF correction = 0.000158
Total force = 0.023734 Total SCF correction = 0.000168
Total force = 0.023734 Total SCF correction = 0.000168
number of scf cycles = 49
number of bfgs steps = 48
energy old = -4400.3520443575 Ry
energy new = -4400.3528674259 Ry
CASE: energy _new < energy _old
new trust radius = 0.0602516409 bohr
new conv_thr = 0.0000000591 Ry
Please help me.
Dr. Narendra Nath Ghosh
Research Associate
University of Gour Banga
Malda-732102
India
Phone No : 09126667601
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