NaCl temperature ramp

Temperature ramping AIMD simulation of NaCL (mp-22851), taken from 0 K to 300 K over 10ps.

Experiment parameters

• MLIP model: M3GNet

• Friction: 0.01 / units.fs

• Time step: 1.0 * units.fs

• Steps: 15000 -> 15ps

• Temperature range: 0 K to 300 K

• Temperature ramp duration: 10ps

• Supercell: 3x3x3

Trajectories

Pretty unexciting. Not sure what I expected but it pretty much maintains the same structure the whole temperature range, which makes sense for NaCl which has a melting point of 801°C. There is an interesting effect from the initialized structure to the first frame (1ps in, 1000 time steps), where the supercell is relaxing into a more stable configurations. Maybe this is a step we should do before starting to ramp up the temperature? The unit cell is relaxed, but does that not necessitate a supercell being relaxed too?

Temperature evolution

Past 9ps, ~250 K, the temperature evolution of the material starts to get a little shaky. The environment reaches 300 K at 10ps so 10ps to 15ps is all at 300 K, but clearly it never reached any real equilibrium with temperature fluctuations of ~50 K still.

Trajectories file