hello i’m doing a simulation with EAM potential with palladium but i get a curious result, the total energy and potential energy have positive values, the temperature is stable in the value that i put, even the was formed a cluster how i hoped but i do not know to interpretate the positive value of the energies, this just occur when is stable. Moreover the RDF analysis show a solid structure. Now i show you an input file that i use.
units real
boundary f f f
atom_style full
dimension 3
read_data data.pdrheam1
replicate 9 10 1
pair_style eam
pair_coeff 1 1 Pd.eam
pair_coeff 2 2 Rh.eam
dihedral_style none
improper_style none
group paladio id 1
group rodio id 2
neighbor 4.0 bin
neigh_modify every 1 delay 1 check yes
fix 2 all nvt temp 100.0 100.0 1
fix reflect all wall/reflect xlo EDGE xhi EDGE ylo EDGE yhi EDGE zhi EDGE zlo EDGE
velocity all create 100 432567 dist uniform
timestep 0.5
thermo 500
thermo_style custom step temp pe etotal ecoul evdwl enthalpy
thermo_modify norm yes
dump video all atom 100 dump.mixA-TIF
restart 1000000 restart.*.mixA-TIF
write_data data.mixA
run 1000000
hello i'm doing a simulation with EAM potential with palladium but i get a
curious result, the total energy and potential energy have positive values,
the temperature is stable in the value that i put, even the was formed a
cluster how i hoped but i do not know to interpretate the positive value of
the energies, this just occur when is stable. Moreover the RDF analysis show
a solid structure. Now i show you an input file that i use.
the same comment that i gave you on the previous input applies.
in this case, there are three items that stand out as "unusual":
- you do replicate on a non-periodic system
- you use real units on a potential type, where usually metal units are used
- you have a ridiculously short time constant (2 times teps) on the thermostat.
remember that the GIGO principle always applies: if you don't feed
LAMMPS the proper input, you don't get proper output.
axel.
and your velocity distribution choice (uniform) is incorrect in both cases.
Thanks
I make all the suggestions that you make me and i find than the particles have so much kinetic energy than they not form aggregates or clusters. so i think that is the velocity distribution how is wrong. i don’t know what could be a correct or recommended velocity distribution for can get palladium clusters in solid state. can you help me with this please?
this is mi .in file:
units metal
atom_style atomic
dimension 3
boundary f f f
read_data data.n1
pair_style eam
pair_coeff 1 1 Pd.eam
group paladio id 1
neighbor 1.0 bin
neigh_modify every 1 delay 10 check yes
fix 2 all nvt temp 300.0 300.0 0.1
fix reflect all wall/reflect xlo EDGE xhi EDGE ylo EDGE yhi EDGE zhi EDGE zlo EDGE
velocity all create 300 1178591
timestep 0.001
thermo 10000
thermo_style custom step temp etotal evdwl enthalpy
thermo_modify norm yes
dump video all atom 1000 dump.n2-TIF
restart 500000 restart.*.n2-TIF
run 500000
thanks
regards
Rosa
Thanks
I make all the suggestions that you make me and i find than the particles
have so much kinetic energy than they not form aggregates or clusters. so i
think that is the velocity distribution how is wrong. i don't know what
could be a correct or recommended velocity distribution for can get
palladium clusters in solid state. can you help me with this please?
i doubt that conclusion. this looks more like you have a bad initial
geometry and/or bad dynamics.