Hi all. I am confused about the output file of emc2. I tried calculation from 300 K to 500 K and there seems a lot of data in the mc.out file from 300K to 500K. So where can I find the meaning of those output number? Besides, how does emc2 work? Does it iterates temperatures and in each temperature iteration, it generates thermaldynamic data in phase equilibrium based on Monta Carlo simulation?
Thanks for your help!
type:
emc2 -h
and look towards the end of the help message.
It can loop over temperature and/or chemical potential and at each of those it runs metropolis monte carlo to equilibrate.
See https://dx.doi.org/10.1088/0965-0393/10/5/304 for more info.
Thank you for your help! But I still have a question that is those data in mc.out file the result of accurate equilibrate calculation or just the result in each loop over temperature?
if -dx is small enough (or -eq and -n large enough), then yes the numbers are accurate.
For the free energy columns, the results are accurate only if you started the code in a low T (for ordered phases) or high T region (for disordered phases) or provided your own -phi0=… value.
So, for example I have such data in mc.out(just as a example):
first row: 300 K -------- x = 0.9 ----- Energy = -0.001
400 K …
500 K …
300 K … x = 0.98 … Energy = -0.0012
400 K …
500 K …
I just need to map all of the data about energy and temperature to obtain the convex hull at finite temperature? That is the surface of energy vs composition and temperature in your manual?
As for chemical potentials, I just need to calculate (free energy(gs=1)- free energy(gs=2))/(composition(gs=1)-composition(gs=2)) to get it?
Besides, is the region of composition I calculate determined by the initial ground state (-gs=…) and the range of chemical potential ? If chemical potential range is large enough, I can cover all the composition?
I think that if you read https://arxiv.org/abs/cond-mat/0201473 all this may become suddenly clearer.