Hello. I am trying to simulate a simple system of Argon molecules in a box (density=1.4 g/cc). When I use the lj units the the energy is conserved (I checked it by setting the mass to be be 1 in the data file and epsilon and sigma to be 1 in pair coeff). However, when I use the real units with actual values of epsilon (0.238) and sigma (3.405) for Argon, the energy is not conserved and i get the following error.
Sorry if this is a fundamental question.
3d Lennard-Jones melt
units real
dimension 3
boundary p p p
atom_style atomic
read_data data.Argon
velocity all create 80 87287 loop geom
pair_style lj/cut 3
pair_coeff 1 1 0.238 3.405
neighbor 0.3 bin
neigh_modify delay 0 every 20 check no
fix 1 all nve
#fix 1 all nvt temp 0.7 0.7 100.0
thermo 10
thermo_style custom density
run 100
ERROR: Lost atoms: original 250 current 244 (…/thermo.cpp:394)
Thanks
Arun
Hello. I am trying to simulate a simple system of Argon molecules in a box (density=1.4 g/cc). When I use the lj units the the energy is conserved (I checked it by setting the mass to be be 1 in the data file and epsilon and sigma to be 1 in pair coeff). However, when I use the real units with actual values of epsilon (0.238) and sigma (3.405) for Argon, the energy is not conserved and i get the following error.
Sorry if this is a fundamental question.
Don’t be sorry; do something about it. This is a very common error and usually means that you did something wrong. Please review the manual for each command you use and check which parameters depend on the choice of units. And also search the mailing list archives for previous questions of the same kind and the resulting discussions.
You can run the exact same calculation in any units system
LAMMPS provides. But as Axel says, your input script
and data file have to specify things in a manner consistent
with the units choice.
Steve