Question A8 Magnesium metal has the hexagonal close packed structure, with unit cell parameters a = 3.209 Å and c = 5.211 Å. It can be modelled as a free electron gas to which each atom contributes two electrons. a) Calculate the electron concentration, the Fermi wavevector, and hence the Fermi energy, giving your answer in eV. b) The Fermi energy is many times greater than the energy required to boil magnesium! Explain briefly how it is possible for electrons in magnesium to have so great an energy.

Question A8 Magnesium metal has the hexagonal close packed structure, with unit cell parameters a = 3.209 Å and c = 5.211 Å. It can be modelled as a free electron gas to which each atom contributes two electrons. a) Calculate the electron concentration, the Fermi wavevector, and hence the Fermi energy, giving your answer in eV. b) The Fermi energy is many times greater than the energy required to boil magnesium! Explain briefly how it is possible for electrons in magnesium to have so great an energy.