In a solid state book I am reading the 3 dimensional electron gas is derived. It says, "An unconfined electron in free space is described by the Schrodinger equation where m is the free-electron mass.
The solutions of the equation, phi(r)=1/(2pi)^3 Exp(ik.r) are plane waves labelled by the wavevector k=(kx,ky,kz)."
The Attempt at a Solution
I know that Exp(ikx) is not normalizble from -infinity to infinity, so how can you determine the normalization constant?
Thanks for the help