Commet on the assingment 1d from Module II

 Dear All,

I have a commet regarding 1d from Module II. Firstly, let me explain why do we deal with (d) part at all. Indeed we could derive what is required in (a-c) and stop there. However, by proposing (d) I wanted to make a point that 1D model is readily applicable for 3D latticestoo (!), as long as one looks in a specific direction (see e.g. Eq 59 in p82 of Kittels book). However, be aware to use values with consistent dimentions when calculating (d)! Finally, I propose we stop after calculating maximum frequency and omit calculating the vibration amplitude. Frequency is good enough.

Good luck.

WR,

Andrej.