Sommerfeld model's assumption

In this model free electron model is modified by tacking into account quantum statistics and the Pauli exclusion principle.
- Free electrons are valence electrons of composing atoms
- A valence electron in metal finds itself in the field of all ions and that of other electrons. The mutual repulsion between the electrons is neglected and the potential filed representing the attractive interaction of ions is assumed to be completely uniform every where inside the solid.
- Distribution of energy in an electron gas obeys the Fermi-Dirac quantum statistics.
- Only electrons close to the Fermi energy are scattered.
The energy levels are filled in accordance with the Pauli’s exclusion principle according to which an energy level can accommodate at the most two electrons, one with spin up and one with spin down.