Infinite-well interband selection rule
= Infinite-well interband selection rule
In an <infinite square well>, <electron> and hole envelopes are the same normalized <sine> functions even when their <effective masses> differ. In the electric dipole and envelope approximations, their overlap is $\int F_{n^{\prime}}^*(z)F_n(z)\,dz=\delta_{n^{\prime}n}$. The same-index rule is an ideal-envelope rule, separate from Bloch-state <polarization> selection rules.