Nanoparticle movement

Hi
I am simulating the boiling process of argon fluid on the copper surface, where a Platinium nanoparticle is placed at a distance of 0.6 nm near the copper surface at the beginning of the simulation. My question is: why the nanoparticle does not move during the simulation?
In addition to the dump file, I logged the movement, velocity, and rotational speed of the nanoparticle during the boiling process and almost nothing can’t be seen.
I appreciate it if you check this part of my code to help me if I am doing something wrong.

Thank you.

#######  Code   #######

#region Cu1 belongs to stagnant copper atoms 
#region Cu2 belongs to heat source copper atoms 
#region Cu3 belongs to real copper atoms that transfer heat from heat source to the argon fluid


fix           2 Cu1 langevin ${Tstart} ${Tstart} 0.5 654848
fix           3 Cu1 nvt temp ${Tstart} ${Tstart} 0.5

fix           4 Cu2 langevin ${Tstart} ${Tstart} 0.5 654841
fix           5 Cu2 nvt temp ${Tstart} ${Tstart} 0.5

fix           6 Cu3 langevin ${Tstart} ${Tstart} 0.5 654847
fix           7 Cu3 nvt temp ${Tstart} ${Tstart} 0.5

fix           8 Ar langevin  ${Tstart} ${Tstart} 0.5 654843
fix           9 Ar nvt temp  ${Tstart} ${Tstart} 0.5

fix           08 Pt langevin  ${Tstart} ${Tstart} 0.5 654843
fix           09 Pt nvt temp  ${Tstart} ${Tstart} 0.5

#------------ Run a Simulation (Equilibrium Process 1)------------#
run           50000

#------------ Run a Simulation (Equilibrium Process 2)------------#
unfix          9
unfix          09

fix            11 Ar nve
fix            011 Pt nve

run            50000

#------------ Run a Simulationm (Non-Equilibrium Process)------------#
unfix          2
unfix          3
unfix          4
unfix          5
unfix          6
unfix          7
unfix          8
unfix          08

fix	        12 Cu1 setforce 0 0 0
fix            13 Cu2 nvt temp ${Tstart} ${Tfinal} 0.5
fix            14 Cu3 nve

run            1000000

Why should it move? There is nothing in your input fragment that drives any motion of that group of atoms except for thermal fluctuations.

If there is a syntax error, LAMMPS will tell you.

If there is a conceptual error, that is something for you to work out, possibly with the assistance of your adviser or mentor or tutor or similar. Without knowing about the details of your research and with only a fraction of your input it is essentially impossible to make any meaningful assessment.

Nanoparticles move through the boiling process because of high pressure zone that is made by argon atoms…the reason of heat transfer enhancement is micro convection of nanoparticle. In my simulation the movement can not be seen.

What is the time scale of that process?

I did not say syntax error, I said help me if I am doing something wrong…this means if I specified a zone or function or … wrong.
I have to be specific, I mean is there any constraint that I should apply to the nanoparticle to gain this movement? In real, the movement is because of argon atoms pressure…how can I specify this?

I am doing the simulation in Nano scale.
I said the particle has micro convection in macro scale…so there shoud be a movement in nanoscale too.

Not necessarily. At the dimensions available to simulations, you also have finite size effects and specifically local fluctuations are limited, so you may not be able to have the convection form and even if the size would be sufficient, you may need to have to induce it.

For example melting and freezing have a significantly larger hysteresis at nanoscale dimensions than for macroscopic systems, since the fluctuations necessary to activate the process are not as likely.

Many of the choices you make in simulations are not binary “right” or “wrong”. How can you tell which is which? When a simulation does what you expect? Well, your expectation may not be justified and thus the simulation correct, but your input not representing the expected system. How could an outsider tell that difference, and from an input fragment to boot with very limited information.

So, like I already wrote, if there is something conceptually wrong (i.e. not a syntax error), you have to talk to somebody that has experience with the specific area of research you are doing. It is highly unlikely that somebody here has done something similar.