hi:
I use NPT for my MD. I found my system drifting and rotating. And two atoms leave my system. I think I should zero the linear and anguar moment, so I use the comand as :
fix 1 all npt 80.0 80.0 10 aniso NULL NULL NULL NULL 0.0 0.0 10 drag 1.0
fix 2 all momentum 10 linear 1 1 1 angular
Adding the comand fix momentum, but I found system’s drifting and rotating still appear. And two atoms still leave my system.Why?
this is in script:
3d al-cu simulation
units metal
boundary s s p
atom_style atomic
lattice bcc 3.610
region box block 0 10.0 0 10.0 0 40.0
create_box 2 box
create_atoms 1 box basis 2 2
pair_style eam/alloy
pair_coeff * * AlCu.eam.alloy Al Cu
neighbor 2.0 bin
neigh_modify delay 5
velocity all create 80.0 5812775 rot yes
fix 1 all npt 80.0 80.0 10 aniso NULL NULL NULL NULL 0.0 0.0 10 drag 1.0
fix 2 all momentum 10 linear 1 1 1 angular
thermo_style custom step temp pzz etotal vol
thermo 10
dump 1 all atom 10000 1dump11.atom
restart 50000 1npt11.restart
timestep 0.001
run 50000
unfix 1
fix 1 all npt 80.0 80.0 100 aniso NULL NULL NULL NULL 0.0 0.0 100 drag 0.2
unfix 2
fix 2 all momentum 1000 linear 1 1 1 angular
thermo_style custom step temp pzz etotal vol
thermo 10
dump 2 all atom 50000 1dump12.atom
restart 100000 1npt12.restart
timestep 0.001
run 200000
unfix 1
fix 1 all npt 80.0 80.0 1000 aniso NULL NULL NULL NULL 0.0 0.0 10000
unfix 2
fix 2 all momentum 10000 linear 1 1 1 angular
thermo_style custom step temp pzz etotal vol
thermo 10
dump 3 all atom 10000 1dump13.atom
restart 100000 1npt13.restart
timestep 0.001
run 500000