I have three elements and a vacancy in the system. I would like to give different range of chemical potential to different elements. How do I make sure the order in the control.in file is correct? I assumed the order in the mcheader.out file should be the order of elements in the control.in.
Yes, the order in the mcheader.out file is the one to follow to decide which column corresponds to which specie (the first column in temperature).
Assuming the last specie is the vacancy and you want to scan the hypercube [100,1000]x[-10,10]x[-10,10]x[-10,10] using a 10x10x10x10 grid,
your control.in should be: