level to which fermions fill up the lowest energy states at absolute zero.

a cutoff energy; the last filled energy state (see figure 31.13)

The average energy per particle when adding particles to a distribution but without changing the entropy or the volume. Chemists refer to this quantity as being the electro-chemical potential

for a metal, the energy corresponding to the highest filled electron state in the valence bond at 0 K.

In physics and Fermi-Dirac statistics, the Fermi energy (EF) of a system of non-interacting fermions is the smallest possible increase in the ground state energy when exactly one particle is added to the system. It is equivalent to the chemical potential of the system in its ground state at absolute zero. It can also be interpreted as the maximum energy of an individual fermion in this ground state.