I wish to ask how one can determine the initial and final values of the chemical potential ? (are these values the difference of free energy for pure components of the ally? if so how does the code work for multi-component systems?)
and how does the code exactly finds other values of the chemical potential using linear extrapolating?
my last question is are these chemical potential values the effective chemical potential?
For multicomponent systems (using memc2) the best way is to use the information contained in chempot.out (that mmaps generates). The chempot.out file contains
(i) the values of the chemical potentials that stabilize all
fixed-composition multiphase equilibria of the system at 0K.
(e.g. in a n-nary system, all the n-phase equilibria)
(ii) values of the chemical potentials that stabilize each of the ground states
at 0K.
For binary systems it’s easier, by default, emc2 lets you specify in a dimensionless form -mu0=x that is explained in the manual:
" If x is integer, x is the chemical potential that
stabilizes a two phase equilibrium between ground state x-1 and
x. (Ground states are numbered starting at 0.) Fractional values
interpolate linearly between these integer values. Negative values
or values larger than the number of ground states - 1 are allowed.
The values of mu are found by linear extrapolation. If the -abs
option is specified, the value of mu are in units of energy per spin
value (as in the output file). (The ground states are read in from
the file gs_str.out .)
"