[lammps-users] A question regarding an example

LAMMPS LAMMPS Mailing List Mirror
1

Hello everyone,

I have one question regarding an example (under folder of bench, in.chain, data.chain, log.9Jan09.chain.fixed.linux.1).
In this simulation, “NVE”+“langevin” are employed, which perform a brownian dynamics.
In the log file, we can see that the temperature and total energy are stable (I ran longer timesteps, they are stable).
My question is that: The total energy is positive, is this system stable or not?
Generally speaking, negative total energy is better for a stable system.

p.s. the files of this example are attached.

Thanks & Best wishes,
Houyang

in.chain (373 Bytes)

log.9Jan09.chain.fixed.linux.1 (1.46 KB)

2

The total energy of the system is arbitrary, and depends on the specific reference state used to define energy. Stable states will have lower energy than the metastable and unstable states nearby in phase space. A total positive energy is thus not inherently “bad,” and is very much a function of the potentials used to specify the interactions between particles.

–AEI