Hello, As we know, the wave function of infinite potential wells form a complete orthogonal base. I have tried now to solve out the wave function for finite potential well, checking the orthogonality, I found that they are no longer orthogonal to each other (I mean the wave function of those boundary states). This is not that understandable to me, since the Hamiltonian is Hermite and the resulting wave function from different eigenvalue (non-degeneracy) should be "always" orthogonal to each other. Could anyone give explanation ? Thank you !