Gentlemen and ladies,?
I have some rookie questions about VC-relax.??? I've pasted the input file and
greps of Total energy, Total Forces and stresses below.?? Its the same problem
of oscillations that has been posted before. ? Here are my questions.
1).?? how can it be that? while the forces and stresses are oscillating the
total energy continues to decrease albeit slowly??? Am I really relaxing fine
but just have a long way to go?
2)??? I've read many posts suggestioning an MD run to determine an effective dt
but I don't think I understand.??? I run molecular dynamics and look for the
oscillation period of the total forces??????? Then use a dt equal to some
fraction of the period?
3)??? I've seen conflicting suggestions on whether the default cell mass is a
good guess.????? any further thoughts on this?
4)?? I'm starting off with "! no symmetries" and hoping to relax to a point
where I find symmetries.??? is VC-relax even appropriate for this application?
thanks in advance!
Tim Mason
Graduate student physics
University of Missouri St. Louis
!??? total energy????????????? =? -130.99725337 Ry
!??? total energy????????????? =? -130.99742389 Ry
!??? total energy????????????? =? -130.99765896 Ry
!??? total energy????????????? =? -130.99788028 Ry
!??? total energy????????????? =? -130.99814044 Ry
!??? total energy????????????? =? -130.99838484 Ry
!??? total energy????????????? =? -130.99862662 Ry
!??? total energy????????????? =? -130.99883535 Ry
!??? total energy????????????? =? -130.99906028 Ry
!??? total energy????????????? =? -130.99921630 Ry
!??? total energy????????????? =? -130.99942817 Ry
!??? total energy????????????? =? -130.99962083 Ry
!??? total energy????????????? =? -130.99984032 Ry
!??? total energy????????????? =? -131.00005894 Ry
!??? total energy????????????? =? -131.00027167 Ry
!??? total energy????????????? =? -131.00032697 Ry
!??? total energy????????????? =? -131.00055195 Ry
!??? total energy????????????? =? -131.00075005 Ry
!??? total energy????????????? =? -131.00092926 Ry
!??? total energy????????????? =? -131.00110579 Ry
!??? total energy????????????? =? -131.00128893 Ry
!??? total energy????????????? =? -131.00152437 Ry
!??? total energy????????????? =? -131.00176666 Ry
!??? total energy????????????? =? -131.00201744 Ry
!??? total energy????????????? =? -131.00222657 Ry
???? Total force =???? 0.025775???? Total SCF correction =???? 0.000281
???? Total force =???? 0.020098???? Total SCF correction =???? 0.000361
???? Total force =???? 0.015661???? Total SCF correction =???? 0.000081
???? Total force =???? 0.016340???? Total SCF correction =???? 0.000253
???? Total force =???? 0.012358???? Total SCF correction =???? 0.000853
???? Total force =???? 0.012918???? Total SCF correction =???? 0.000221
???? Total force =???? 0.011349???? Total SCF correction =???? 0.000287
???? Total force =???? 0.013804???? Total SCF correction =???? 0.000249
???? Total force =???? 0.012754???? Total SCF correction =???? 0.000124
???? Total force =???? 0.016969???? Total SCF correction =???? 0.000230
???? Total force =???? 0.011474???? Total SCF correction =???? 0.000262
???? Total force =???? 0.013177???? Total SCF correction =???? 0.000210
???? Total force =???? 0.010928???? Total SCF correction =???? 0.000265
???? Total force =???? 0.009784???? Total SCF correction =???? 0.000097
???? Total force =???? 0.010154???? Total SCF correction =???? 0.000534
???? Total force =???? 0.023392???? Total SCF correction =???? 0.000539
???? Total force =???? 0.018644???? Total SCF correction =???? 0.000303
???? Total force =???? 0.013266???? Total SCF correction =???? 0.000284
???? Total force =???? 0.012565???? Total SCF correction =???? 0.000137
???? Total force =???? 0.011408???? Total SCF correction =???? 0.000406
???? Total force =???? 0.013103???? Total SCF correction =???? 0.000212
???? Total force =???? 0.011107???? Total SCF correction =???? 0.000195
???? Total force =???? 0.009844???? Total SCF correction =???? 0.000492
???? Total force =???? 0.010155???? Total SCF correction =???? 0.000692
???? Total force =???? 0.014920???? Total SCF correction =???? 0.000309
???????? total?? stress? (Ry/bohr**3)?????????????????? (kbar)???? P=??? 0.85
????????? total?? stress? (Ry/bohr**3)?????????????????? (kbar)???? P=??? 1.09
????????? total?? stress? (Ry/bohr**3)?????????????????? (kbar)???? P=??? 1.44
????????? total?? stress? (Ry/bohr**3)?????????????????? (kbar)???? P=??? 2.07
????????? total?? stress? (Ry/bohr**3)?????????????????? (kbar)???? P=??? 2.36
????????? total?? stress? (Ry/bohr**3)?????????????????? (kbar)???? P=??? 2.74
????????? total?? stress? (Ry/bohr**3)?????????????????? (kbar)???? P=??? 2.96
????????? total?? stress? (Ry/bohr**3)?????????????????? (kbar)???? P=??? 2.95
????????? total?? stress? (Ry/bohr**3)?????????????????? (kbar)???? P=??? 2.92
????????? total?? stress? (Ry/bohr**3)?????????????????? (kbar)???? P=??? 3.35
????????? total?? stress? (Ry/bohr**3)?????????????????? (kbar)???? P=??? 3.21
????????? total?? stress? (Ry/bohr**3)?????????????????? (kbar)???? P=??? 3.13
????????? total?? stress? (Ry/bohr**3)?????????????????? (kbar)???? P=??? 2.91
????????? total?? stress? (Ry/bohr**3)?????????????????? (kbar)???? P=??? 2.85
????????? total?? stress? (Ry/bohr**3)?????????????????? (kbar)???? P=??? 2.61
????????? total?? stress? (Ry/bohr**3)?????????????????? (kbar)???? P=??? 1.46
????????? total?? stress? (Ry/bohr**3)?????????????????? (kbar)???? P=??? 1.75
????????? total?? stress? (Ry/bohr**3)?????????????????? (kbar)???? P=??? 2.29
????????? total?? stress? (Ry/bohr**3)?????????????????? (kbar)???? P=??? 2.03
????????? total?? stress? (Ry/bohr**3)?????????????????? (kbar)???? P=??? 1.97
????????? total?? stress? (Ry/bohr**3)?????????????????? (kbar)???? P=??? 2.01
????????? total?? stress? (Ry/bohr**3)?????????????????? (kbar)???? P=??? 2.26
????????? total?? stress? (Ry/bohr**3)?????????????????? (kbar)???? P=??? 2.44
????????? total?? stress? (Ry/bohr**3)?????????????????? (kbar)???? P=??? 2.66
????????? total?? stress? (Ry/bohr**3)?????????????????? (kbar)???? P=??? 2.59
&CONTROL
calculation = "vc-relax",
prefix = 'n1',
tprnfor = .TRUE.
pseudo_dir = '/home/tim/PWSCF/PSPS',
outdir='/home/tim/tmp'
etot_conv_thr = 1.0D-5,
forc_conv_thr = 0.0004,
dt = 20
nstep = 100
/
&SYSTEM
ibrav = 0, nat = 15, ntyp = 5,
ecutwfc = 40
ecutrho = 480
celldm(1) = 1.889725989
/
&ELECTRONS
mixing_mode = 'plain',
mixing_beta = 0.7,
conv_thr = 1.0D-7,
/
&IONS
ion_dynamics? = 'damp',
ion_damping? = 0.1,
ion_positions = 'from_input',
pot_extrapolation = "second_order",
wfc_extrapolation = "second_order",
upscale = 100,
/
&CELL
press = 0.0,
cell_dynamics = 'damp-w'
/
ATOMIC_SPECIES
Li 1.0 Li.pbe-n-van.UPF
Ca 1.0 Ca.pbe-nsp-van.UPF
N 1.0 N.pbe-rrkjus.UPF
H 1.0 H.pbe-rrkjus.UPF
B 1.0 B.pbe-n-van.UPF
CELL_PARAMETERS
11.03225111 0.49197118 -0.92807585
-0.15038487 5.49373010 -0.38883048
3.04894498 0.25407718 4.19633759
ATOMIC_POSITIONS {crystal}
Li 0.144228066000 0.155479905000 0.105275909000
Ca 0.911201719000 0.659605393000 0.179405853000
?N 0.954182418000 0.066667349000 0.203452528000
?H 0.879987796000 0.160521652000 0.398773311000
?H 0.949093887000 0.150685763000 0.033727675000
?H 0.590246767000 0.244749224000 0.483311768000
?H 0.563997731000 0.067035740000 0.225636766000
?H 0.437455407000 0.306433941000 0.454794956000
?H 0.611216941000 0.379448807000 0.154202770000
?H 0.231109967000 0.728337975000 0.002905585000
?H 0.397236924000 0.644804127000 -0.037067236000
?H 0.288752224000 0.877300760000 0.238936122000
?H 0.231627436000 0.575300194000 0.301639728000
?B 0.550495441000 0.249323405000 0.329678852000
?B 0.288025902000 0.707564656000 0.123296526000
K_POINTS automatic
4 4 4 0 0 0
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