Structural relaxation with force as a convergence criterion
Posted: Wed Sep 02, 2015 10:44 am
Hi guys, I'am a new ABINIT user and have some problem running ABINIT when force "toldff" is used as a convergence criterion.
I have a 32 atoms system, 30 nickel and 2 (neighboring) molybdenum atoms. Initially all atoms are placed on the nickel FCC lattice, however I expect that the Mo-Mo chemical bond will change in lenght and this is what I want to simulate. I allready performed several ABINIT simulations using enegry "toldfe" as a convergence criterion and got nice results. Now, I want to run the same simulation using no MD steps and 500 electronic "ntime" steps in order to see the convergence of the force. However, after 290 SCF steps, no convergence is reached, individual ETOT-s (my former energy criterion) are close to each other, but jump around approx 1 eV.
Below my input file, please comment:
##################################################
# Ni-2Mo material system 2x2x2 lattice parameters in size
# Definition of occupation numbers
occopt 4
tsmear 0.07
# Defines how many energy bands are necessary to conduct a stable simulation. This varialbe is material dependent (insulator, semiconductor,
# metall). In case of occupt not equal to 0 or 2 the specification of nband can be omitted. Instead, the variable fband will be used to automatically
# calculate the rigth number of energy bands. For metallic case the initial value of fband is 0.5.
#nband 1000
fband 0.5
optforces 1 # calculation of forces at each SCF iteration, allowing to use forces as criterion to stop the SCF cycles
optcell 0
ionmov 0
iscf 17 # Integer for Self-Consistent-Field cycles
timopt 2 # show CPU times for the run
# Definition of the atom types
ntypat 2
znucl 28 42 # Nickel, Moybdenum
nsym 0
# activate automatic parallelization
AUTOPARAL 2
# Definition of the cell
acell 3*7.04 angstrom
natom 32 # 32 atoms in the cell
typat 30*1 2*2 # 30 Nickel, 2 Molybdenum
xangst # X-, Y- und Z-coordinates of all atoms in angstroem
#Definition of Nickel atoms
0.880000 0.880000 0.880000
0.880000 0.880000 4.400000
0.880000 2.640000 2.640000
0.880000 2.640000 6.160000
0.880000 4.400000 0.880000
0.880000 4.400000 4.400000
0.880000 6.160000 2.640000
0.880000 6.160000 6.160000
2.640000 0.880000 2.640000
2.640000 0.880000 6.160000
2.640000 2.640000 0.880000
2.640000 2.640000 4.400000
2.640000 4.400000 6.160000
2.640000 6.160000 0.880000
2.640000 6.160000 4.400000
4.400000 0.880000 0.880000
4.400000 0.880000 4.400000
4.400000 2.640000 6.160000
4.400000 4.400000 0.880000
4.400000 4.400000 4.400000
4.400000 6.160000 2.640000
4.400000 6.160000 6.160000
6.160000 0.880000 2.640000
6.160000 0.880000 6.160000
6.160000 2.640000 0.880000
6.160000 2.640000 4.400000
6.160000 4.400000 2.640000
6.160000 4.400000 6.160000
6.160000 6.160000 0.880000
6.160000 6.160000 4.400000
#Definition of Molybdenum atoms
2.640000 4.400000 2.640000
4.400000 2.640000 2.640000
#Definition of the planewave basis set
ecut 350 eV
pawecutdg 500 eV
# Exchange-correlation functional
ixc -101130 # for PBE GGA
kptopt 1 # kpunktoption fuer groundstatecalc
# Definition of the k-point grid
ngkpt 6 6 6 # This is a 2x2x2 FCC grid, based on the primitive vectors
nshiftk 1
shiftk 0.5 0.5 0.5
# Define electronic integration steps
nstep 500 # maximum number of SCF cycles
toldff 0.0001 # for structural relaxation, it is better to use force
# convergence than energy convergence (toldff for electrons and tolmxf for ions)
########################################################################################
Here also a short "grep" of the log file. Can someone tell me what other columns, I couldnt unterstand it from log file itself.
ETOT 275 -5232.4434728059 1.054E+00 2.031E-01 1.537E+03 4.767E-01 2.731E-01
ETOT 276 -5233.0374418101 -5.940E-01 2.093E-01 1.311E+03 3.096E-01 2.004E-01
ETOT 277 -5234.0053537850 -9.679E-01 2.413E-01 1.273E+03 2.705E-01 1.713E-01
ETOT 278 -5233.1067522228 8.986E-01 2.257E-01 1.264E+03 2.816E-01 3.006E-01
ETOT 279 -5233.7853387279 -6.786E-01 2.602E-01 1.286E+03 4.170E-01 1.783E-01
ETOT 280 -5233.6793145517 1.060E-01 1.654E-01 1.274E+03 2.776E-01 2.488E-01
ETOT 281 -5232.3101713091 1.369E+00 2.237E-01 1.567E+03 4.888E-01 2.489E-01
ETOT 282 -5232.6880242259 -3.779E-01 2.226E-01 1.290E+03 3.643E-01 1.652E-01
ETOT 283 -5233.7286984310 -1.041E+00 2.089E-01 1.607E+03 4.197E-01 3.266E-01
ETOT 284 -5232.4360593211 1.293E+00 2.001E-01 1.539E+03 4.718E-01 2.688E-01
ETOT 285 -5233.0218131538 -5.858E-01 2.223E-01 1.307E+03 3.040E-01 2.131E-01
ETOT 286 -5233.9881202503 -9.663E-01 2.830E-01 1.271E+03 2.773E-01 1.717E-01
ETOT 287 -5233.0238243918 9.643E-01 3.291E-01 1.262E+03 2.783E-01 2.983E-01
ETOT 288 -5233.8048254696 -7.810E-01 2.418E-01 1.285E+03 4.142E-01 1.768E-01
ETOT 289 -5233.5672227615 2.376E-01 1.910E-01 1.272E+03 2.807E-01 2.496E-01
ETOT 290 -5232.3370664490 1.230E+00 2.087E-01 1.565E+03 4.958E-01 2.461E-01
Best regards
Alen
I have a 32 atoms system, 30 nickel and 2 (neighboring) molybdenum atoms. Initially all atoms are placed on the nickel FCC lattice, however I expect that the Mo-Mo chemical bond will change in lenght and this is what I want to simulate. I allready performed several ABINIT simulations using enegry "toldfe" as a convergence criterion and got nice results. Now, I want to run the same simulation using no MD steps and 500 electronic "ntime" steps in order to see the convergence of the force. However, after 290 SCF steps, no convergence is reached, individual ETOT-s (my former energy criterion) are close to each other, but jump around approx 1 eV.
Below my input file, please comment:
##################################################
# Ni-2Mo material system 2x2x2 lattice parameters in size
# Definition of occupation numbers
occopt 4
tsmear 0.07
# Defines how many energy bands are necessary to conduct a stable simulation. This varialbe is material dependent (insulator, semiconductor,
# metall). In case of occupt not equal to 0 or 2 the specification of nband can be omitted. Instead, the variable fband will be used to automatically
# calculate the rigth number of energy bands. For metallic case the initial value of fband is 0.5.
#nband 1000
fband 0.5
optforces 1 # calculation of forces at each SCF iteration, allowing to use forces as criterion to stop the SCF cycles
optcell 0
ionmov 0
iscf 17 # Integer for Self-Consistent-Field cycles
timopt 2 # show CPU times for the run
# Definition of the atom types
ntypat 2
znucl 28 42 # Nickel, Moybdenum
nsym 0
# activate automatic parallelization
AUTOPARAL 2
# Definition of the cell
acell 3*7.04 angstrom
natom 32 # 32 atoms in the cell
typat 30*1 2*2 # 30 Nickel, 2 Molybdenum
xangst # X-, Y- und Z-coordinates of all atoms in angstroem
#Definition of Nickel atoms
0.880000 0.880000 0.880000
0.880000 0.880000 4.400000
0.880000 2.640000 2.640000
0.880000 2.640000 6.160000
0.880000 4.400000 0.880000
0.880000 4.400000 4.400000
0.880000 6.160000 2.640000
0.880000 6.160000 6.160000
2.640000 0.880000 2.640000
2.640000 0.880000 6.160000
2.640000 2.640000 0.880000
2.640000 2.640000 4.400000
2.640000 4.400000 6.160000
2.640000 6.160000 0.880000
2.640000 6.160000 4.400000
4.400000 0.880000 0.880000
4.400000 0.880000 4.400000
4.400000 2.640000 6.160000
4.400000 4.400000 0.880000
4.400000 4.400000 4.400000
4.400000 6.160000 2.640000
4.400000 6.160000 6.160000
6.160000 0.880000 2.640000
6.160000 0.880000 6.160000
6.160000 2.640000 0.880000
6.160000 2.640000 4.400000
6.160000 4.400000 2.640000
6.160000 4.400000 6.160000
6.160000 6.160000 0.880000
6.160000 6.160000 4.400000
#Definition of Molybdenum atoms
2.640000 4.400000 2.640000
4.400000 2.640000 2.640000
#Definition of the planewave basis set
ecut 350 eV
pawecutdg 500 eV
# Exchange-correlation functional
ixc -101130 # for PBE GGA
kptopt 1 # kpunktoption fuer groundstatecalc
# Definition of the k-point grid
ngkpt 6 6 6 # This is a 2x2x2 FCC grid, based on the primitive vectors
nshiftk 1
shiftk 0.5 0.5 0.5
# Define electronic integration steps
nstep 500 # maximum number of SCF cycles
toldff 0.0001 # for structural relaxation, it is better to use force
# convergence than energy convergence (toldff for electrons and tolmxf for ions)
########################################################################################
Here also a short "grep" of the log file. Can someone tell me what other columns, I couldnt unterstand it from log file itself.
ETOT 275 -5232.4434728059 1.054E+00 2.031E-01 1.537E+03 4.767E-01 2.731E-01
ETOT 276 -5233.0374418101 -5.940E-01 2.093E-01 1.311E+03 3.096E-01 2.004E-01
ETOT 277 -5234.0053537850 -9.679E-01 2.413E-01 1.273E+03 2.705E-01 1.713E-01
ETOT 278 -5233.1067522228 8.986E-01 2.257E-01 1.264E+03 2.816E-01 3.006E-01
ETOT 279 -5233.7853387279 -6.786E-01 2.602E-01 1.286E+03 4.170E-01 1.783E-01
ETOT 280 -5233.6793145517 1.060E-01 1.654E-01 1.274E+03 2.776E-01 2.488E-01
ETOT 281 -5232.3101713091 1.369E+00 2.237E-01 1.567E+03 4.888E-01 2.489E-01
ETOT 282 -5232.6880242259 -3.779E-01 2.226E-01 1.290E+03 3.643E-01 1.652E-01
ETOT 283 -5233.7286984310 -1.041E+00 2.089E-01 1.607E+03 4.197E-01 3.266E-01
ETOT 284 -5232.4360593211 1.293E+00 2.001E-01 1.539E+03 4.718E-01 2.688E-01
ETOT 285 -5233.0218131538 -5.858E-01 2.223E-01 1.307E+03 3.040E-01 2.131E-01
ETOT 286 -5233.9881202503 -9.663E-01 2.830E-01 1.271E+03 2.773E-01 1.717E-01
ETOT 287 -5233.0238243918 9.643E-01 3.291E-01 1.262E+03 2.783E-01 2.983E-01
ETOT 288 -5233.8048254696 -7.810E-01 2.418E-01 1.285E+03 4.142E-01 1.768E-01
ETOT 289 -5233.5672227615 2.376E-01 1.910E-01 1.272E+03 2.807E-01 2.496E-01
ETOT 290 -5232.3370664490 1.230E+00 2.087E-01 1.565E+03 4.958E-01 2.461E-01
Best regards
Alen