[Pw_forum] on variable cell optimization
Eduardo Ariel Menendez P
emenendez at macul.ciencias.uchile.cl
Thu Jan 27 23:25:07 CET 2005
Hello,
I am trying to perorm a variable cell optimization, but I do nont know how
to relax the stress.
At the beginnig I have this stress report
entering subroutine stress ...
total stress (ryd/bohr**3) (kbar) P=
-65.91
-0.00046851 -0.00000003 0.00000033 -68.92 -0.01 0.05
-0.00000003 -0.00046821 -0.00000018 -0.01 -68.88 -0.03
0.00000033 -0.00000018 -0.00040740 0.05 -0.03 -59.93
And after 12 steps I have this:
entering subroutine stress ...
total stress (ryd/bohr**3) (kbar) P=
-65.91
-0.00046853 -0.00000004 0.00000033 -68.92 -0.01 0.05
-0.00000004 -0.00046825 -0.00000019 -0.01 -68.88 -0.03
0.00000033 -0.00000019 -0.00040737 0.05 -0.03 -59.93
There is no stress oscillation in the intermediate steps, the forces are
below the force threshold forc_conv_thr REAL ( default = 1.0D-3 )
and the energy histort seems converged as defined by the deault threshold
etot_conv_thr REAL ( default = 1.0D-4 )
! total energy = -762.00561350 ryd
! total energy = -762.00561283 ryd
! total energy = -762.00560983 ryd
! total energy = -762.00560492 ryd
! total energy = -762.00559677 ryd
! total energy = -762.00558778 ryd
! total energy = -762.00557901 ryd
! total energy = -762.00555677 ryd
! total energy = -762.00555691 ryd
! total energy = -762.00551207 ryd
! total energy = -762.00553888 ryd
! total energy = -762.00544708 ryd
Please, tell me why the stress is not released, and why the simulation
does not stop.
This is the input file
&control
calculation='vc-relax'
restart_mode='from_scratch',
tstress = .true.
tprnfor = .true.
prefix='tisic',
pseudo_dir = '/home/gonzalo/eariel/Compilaciones/Espresso/pseudo',
outdir='./'
/
&system
ibrav= 0, celldm(1) =5.7778399,
nat= 12, ntyp= 3,
ecutwfc =60.0
ecutrho = 320.0 ,
occupations = 'smearing' ,
degauss = 0.02 ,
smearing = 'fermi-dirac' ,
/
&electrons
diagonalization='david'
mixing_mode = 'plain'
conv_thr = 1.0d-8
mixing_beta = 0.7
/
&ions
upscale=10
trust_radius_max = 0.1
trust_radius_ini = 0.1
/
&CELL
press=0.d0,
cell_dynamics='damp-w'
/
ATOMIC_SPECIES
Ti 47.867 Ti.vdb.UPF
Si 28.0855 Si-ca-ggjr.UPF
C 12.010 C.pz-rrkjus.UPF
CELL_PARAMETERS
1.000000 0.000000 0.000000
-0.500000 0.866025 0.000000
0.000000 0.000000 5.764022
ATOMIC_POSITIONS crystal
Ti 0.000000000 0.000000000 0.000000000
Ti 0.000000716 -0.000449249 0.499925429
Ti 0.666423342 0.333262850 0.133989450
Ti 0.333333000 0.666667000 0.633906018
Ti 0.333295794 0.666847382 0.866005352
Ti 0.666623159 0.332895739 0.365913496
Si -0.000234387 -0.000347156 0.249920409
Si 0.000000000 0.000000000 0.750000000
C 0.333172599 0.666627154 0.072080546
C 0.666669370 0.333119893 0.571915905
C 0.666633759 0.333400448 0.927992237
C 0.333314765 0.666070328 0.427808834
K_POINTS automatic
10 10 2 0 0 0
Thanks
Eduardo A. Menendez Proupin
Department of Physics
Faculty of Science
University of Chile
Las Palmeras 3425
Ñuñoa, Santiago
Chile
Phone: 56+2+678 74 11
http://fisica.ciencias.uchile.cl/~emenendez/
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