@@ -201,7 +201,7 @@ A joint absorbtion of a photon and a phonon collision may excite an electron acr
## Exercises
### Exercise 1: 3D Fermi surfaces
Using the [periodic table](fermi_surfaces) of the Fermi surfaces (or the static images at https://www.phys.ufl.edu/fermisurface/ if 3D does not work for you), answer the following questions:
Using the [periodic table](../fermi_surfaces) of the Fermi surfaces (or the static images at https://www.phys.ufl.edu/fermisurface/ if 3D does not work for you), answer the following questions:
1. Find 4 elements that are well described by the nearly-free electron model and 4 that are poorly described by it.
2. Is the Fermi surface of lithium or potassium better described by the free electron model? What about nearly-free electron model? Why?
