Thermostate atoms

Dear Dr. Alex

Thank you so much for your help and also for your quick response.

I simulate the buckling of CNT under the radial pressure through displace atoms in middle section of tube (group 1) with fixed boundary conditions at the two ends of CNT (group 2 &3 with five and eight raw of atoms at two ends of CNT), as below:

label looplable

displace_atoms 2 move 0 0 0 units box

displace_atoms 3 move 0 0 0 units box

displace_atoms 1 move v_x2 v_y2 0 units box

fix 2 1 nvt temp 300 300 0.01

thermo_style custom step temp vol pe press v_y1 v_x1

run 5000

next Nstep

jump in.cnt looplable

(Note that there are 2208 atoms in this simulation of CNT which 1896 atoms are in group 1 and 120 and 192 residual atoms are in group 2 &3)

I dont know which section of CNT should be considered to impose nvt command on its atoms. When I impose nvt on middle section of CNT (group1), as:

fix 2 1 nvt temp 300 300 0.01

the buckling does not take place because through nvt command the pressure is removed.
Please help me.
Thank you.

Dear Dr. Alex
Thank you so much for your help and also for your quick response.

I simulate the buckling of CNT under the radial pressure through displace
atoms in middle section of tube (group 1) with fixed boundary conditions at
the two ends of CNT (group 2 &3 with five and eight raw of atoms at two
ends of CNT), as below:

‚Äčthis is not really a question about ‚ÄčLAMMPS, but about your research. this
is something your should discuss with your adviser and your collaborator.
this mailing list is no replacement for that. i for one have no interest in
your field of research and/or to fill in for your adviser.

there is just one question about this in general: why use a thermostat at
all? what does your CNT exchange energy with? and how?

axel.

I only want to relax CNT after imposing radial pressure through using nvt command.