[lammps-users] About equilibration

hello all,
I want to equilibrate SiO2substrate.

However, equilibration causes twisting of the SiO2 substrate.

Is it wrong to fix the SiO2 substrate during equilibration with the fix spring / self command to reduce twisting?

Please let me know if there is another way to prevent twisting during equilibration.

Also I have another approach to fix only the bottom layer of the foundation
I am also considering.

Below is my script

Thanks in advance, Rusty

If you add forces to a fix, you are equilibrating your system to the state with those forces present.
As soon as you remove the fix, then your system is no longer equilibrated.

The correct approach is not to suppress the symptom (i.e. the unwanted deformation of your system) but rather to try and learn where this is coming from and then remove the cause or set up your system in a way that this doesn’t happen in the first place.

There is not enough information present to make a more specific recommendation.

Thank you for answering

I want to put graphene on the SiO2 substrate.

I would like to read the coordinates of SiO2 and graphene created by Material Studio with lammps and consider the effect of aspect ratio and temperature.

so that,
I am confused because graphene cannot be placed if the SiO2 board is twisted.

2021年5月27日(木) 20:43 Axel Kohlmeyer <[email protected]>:

You need to discuss how to properly prepare your simulation setup with your adviser/supervisor.
This is not really a LAMMPS problem, but a general MD simulation knowledge/experience issue.


The size of the board is 150 x 80 x 10 Å.

Tersoff is used for the potential

2021年5月28日(金) 11:49 Chowdhury, Sanjib <[email protected]>:

What is the size of your SiO2 substrate? Are you using right force field for SiO2.

Make sure that your model and boundary conditions are correct.

If the substrate’s thickness is not very low compared to its lateral dimensions, I wouldn’t expect twisting or distortion during equilibration.