How to get a snapshot of emc2 calculation

Dear Axel,

I am learning the emc2 code recently. I would like to know how could I get more information\data about the detail process of Monte Carlo simulation, such as the distribution of the alloy system at a certain temperature and certain elemental ratio.
If I want to get a snapshot (like the figure below) of the system when running Monte Carlo calculation, How could I do?
Thank you very much!

Kesson

Maybe -opss or -opss will help?

good answer!

Thanks for the above answers!

Dear Axel,

I get a puzzle about the meaning of this snapshot. Is this snapshot a random or the last one of the equilibrium state, or the one which synthesised all the states of equilibrium?
I would like to konw that just one snapshot could represent the thermodynamic equilibrium at a finite Temperature? How could I get many snapshots of the equilibrium?

Another problem is also puzzling me. When I run emc2 tests and set the parameter -dx=0.001 & -er=43,45 or 48, the tests runs well, while when I set -dx=0.001 & -er=42,44 or 47, the tests wolud run all the time, and coldn’t end the tests for a very long time. I don’t know why?

Waiting for the replies, thank you very much!

Kesson

The mcsnapshot.out file only contains the status of the Monte Carlo cell at the end of the calculations. To get one snapshots at each set of condition (T,mu) use the -opss=filename0000.out option.
The code never outputs an "average" configuration.

You could set up runs where temperature varies by a negligible amount to get many snapshots, e.g.
-T0=1000 -T1=1001 -dT=0.01 -opss=filename0000.out

I am not sure why some runs take longer to converge. Could it be that the cell size are compatible with the periodicity of structure that forms in equilibrium while others are not?

Dear Axel,

I run emc2 many times with the same input setting parameters, while the output seems very different. Is there something wrong with my input setting? How to deal with the different results, which snapshot is acceptable?

The following are the input setting and part of mc.outs of two tests.
emc2 -T0=2000 -mu0=0.5 -mu1=2.5 -dmu=0.02 -er=35 -gs=0 -k=8.617e-5 -cm -x=0.0 -eq=8000 -n=5000 -o=mc.out -opss=mcsnapshot.out&
2000.000000 0 0.081070 0.000000 (first line of mc.out corresponds to the snapshot-1)
2000.000000 0 0.074995 0.000000 (first line of mc.out corresponds to the snapshot-2)

Looking for tips:
Could I get more information(snapshot and energy of every steps) about the whole process including equilibration time and the averaging time through ATAT?
Is there a tool\way to show the figure of snapshot.out directly?

Thank you very much!

You are running at constant composition (-cm => canonical mode). But your system may be in the middle of a miscibility gap, so it phase separates. The direction of the interfaces created is random (in your 2nd example the interface is facing us). This is completely normal.