I am using metal units wit LJ potential.
I want to setup temperature of simulation to 850 kelvin.
I am giving temperature using the commend
velocity all create 850 4928459
But the desired temperatue is not attained in simulation.
you are setting an initial temperature with this command.
please grab your MD text book and read up on “equilibration” and “thermostat” algorithms.
axel.
I am using fix npt to equliberate the temperature
velocity all create 850 4928459
fix 1 all npt temp 850 850 0.05 x 0.0 0.0 1.0 y 0.0 0.0 1.0
there is not enough information here to say anything.
Hre is full input script:
units metal
dimension 3
boundary p p p
atom_style atomic
read_data grain1.data
read_data grain2.data add append shift 0 0 100
region lowergrain block -128.07 128.07 -10.12 10.12 -50 45
group LG region lowergrain
mass 1 26.9
mass 2 58.6
pair_style lj/cut 8.5
pair_coeff 1 1 0.50722 2.5
pair_coeff 2 2 1 0.2
pair_coeff 1 2 .712 1.35
neighbor 2.0 bin
neigh_modify delay 10 check yes
delete_atoms overlap 1.0 all all
min_style cg
minimize 10e-15 10e-15 1000 1000
set group LG type/fraction 2 0.05 12393
timestep 0.001
velocity all create 850 4928459
fix 1 all npt temp 850 850 0.05 x 0.0 0.0 1.0 y 0.0 0.0 1.0
run 100000
thermo 100
fix 23 all orient/fcc 0 1 4.05 0.0 0.25 0.75 gb1.vec gb2.vec
compute 15 all reduce sum f_23[2]
fix 3 all ave/time 100 1 100 c_15 file foutput
dump pics3 all cfg 40000 model.*.cfg mass type xs ys zs id type f_23[2]
dump_modify pics3 element Al Ni
run 800000
unfix 23
unfix 3
can’t say much more with this.
you have some rather unusual LJ potential parameters for the choice of units and masses.
can this setup conserve energy with fix nve??
axel.