4. Chemical potential tutorial
4.1. Introduction
In this tutorial, you will see how to compute the chemical potential of
carbon in the diamond phase. In DFT, this is simple the total energy per
atom. In general, the chemical potential depends on thermodynamic
variables likes pressure and temperature. Here we’ll simply get the
chemical potential of the zero temperature ground state. We thus use the
equilibrium lattice constant which may be found using an equation of
states fit (see Equation of states tutorial). We simply perform
the calculation defined in scf.input
as follows
mpiexec -n 16 rescu --smi -i scf.input
Then load the results and get the total energy per atom.
HA2EV = 27.21138602;
mrc = load('results/scf.mat');
etot = mrc.energy.Etot * HA2EV;
etot = etot / numel(mrc.atom.element);
fprintf('mu = %f eV\n', etot)
The last line will print
mu = -163.887300 eV