Dear lammps users
i want to create a perfect crystal of nickel with PBC in all 3 directions. here is my input:
units real
dimension 3
boundary p p p
atom_style charge
Dear lammps users
i want to create a perfect crystal of nickel with PBC in all 3 directions.
here is my input:
[...]
region box block 0 25 0 25 0 30 units box
create_box 1 boxlattice fcc 3.52 orient x 1 -1 0 orient y 1 1 -2 orient z 1
1 1
create_atoms 1 region box
two questions here:
have you checked that the periodicity of your rotated crystal is
commensurate with the box dimensions? my guess is it is not.
why rotate a homogeneous bulk system? each subsystem you pick has to
give identical results anyway.
[...]
velocity all create 300.0 4928459 rot yes dist gaussian
fix 1 all temp/rescale 1 300.0 300.0 10.0 1.0
fix 2 all nvt temp 300.0 300.0 10.0 drag 2.0
run 50000
please inspect the output of your simulation. it should print a *BIG
FAT WARNING* that you are thermalizing your atoms *twice*. as has been
explained on this mailing list many times, as will as is stated in the
manual, this will lead to a complete bogus trajectory. apart from
that, using temp/rescale is about the worst thing you can do to
thermalize a system like this. temp/rescale needs to be treated like a
controlled substance and only people that have proven to know what
they are doing may be allowed to use it. the cases where it is a good
choice are like 1 in a 1000.
a few steps after running when visualize dump file via VMD ,lattice
structure is very disordered and this configuration will exist at the end of
the simulation.i also check total energy,potential energy and charge of
metal lattice but results do not converge.
how can i solve it?
follow the GIGO principle and make sure that your input is meaningful.
bad input -> bad trajectory.
axel.
Dear Axel
thanks for replying, i changed box dimension , boundary condition,and deleted temp/rescale command, but it does not work. i also change nvt to npt and nve but it does not work . i can not recogenize what is incorrect in my input.
Best Regard.
Dear Axel
thanks for replying, i changed box dimension , boundary condition,and
deleted temp/rescale command, but it does not work. i also change nvt to npt
"it doesn't work" is a useless description.
and nve but it does not work . i can not recogenize what is incorrect in my
input.
i already pointed it out in my previous mail and you didn't say you
changed the the orientation, or gave a reason why this would be needed
(it certainly isn't needed for a bulk system).
changing input parameters randomly without understanding why is a
pointless exercise. check if your system is a correct periodic
replication. there have been numerous previous discussions on this
subject that can be found in the mailing list archives where people
report very similar problems. look them up and learn.
axel.