[lammps-users] How to move a group in a constant velocity?

Hi, lammps users.

I've used

#......................set up the system
#minimize

minimize 1.0e-10 1.0e-12 100 1000

# fix nvt on water and lipid
fix 1 other nvt 323.15 323.15 100 #use nvt instead of npt
because it is hard to reach equilibrium.
# fix all tip3p water model
fix 2 other shake 1e-6 500 0 m 1.0 a 31
# output forces acted upon sio2 sphere
fix f_sio2 sio2 ave/time 1 300 1000 f_sio2[1] f_sio2[2] f_sio2[3] file f_sio2
# hold lower lipid bilayer
fix hold_lipid lower_lipid spring/self 100
# generate initial velocity
velocity other create 323.15 1245678 dist uniform
veloctiy sio2 set 0 0 -0.2 units box
fix sio2 sio2 setforce 0 0 0
#......................run code

But the result is sio2 did not move.
what's wrong?

Any comments is appreciable.

Di Cheng

University of Science and Technology of China
Hefei, Anhui Province 230026
P. R. China
E-mail: [email protected]
Tel.: +86-15321055911

It seems like sio2 group is not included in any fix. Thats why atomic positions are not changing. nvt is running on “other”.
try fix 2 sio2 nve (along with velocity and setforce command).

Varshney

Thanks, I will have a try.

Di Cheng

University of Science and Technology of China
Hefei, Anhui Province 230026
P. R. China
E-mail: [email protected]
Tel.: +86-15321055911