I hope someone out there can help me with this fairly simple but specific question about the Mott 3-D variable range hopping conduction model. Mott theory has the energy difference between hopping sites as: ΔE ≈ 1 / g0rD Where g0 density of states near the Fermi surface, D is the dimension of hopping (1,2,3) and r is the distance between hopping sites. My question is about using this numerically. I don't know how to calculate or look up a specific number for g0 for a particular material. Also, what are the units of this quantity usually? States/volume? Energy/volume? The second makes sense because the units work out for 3D, but is that the usual unit of density of states?