momentum operator eigenstates/eigenvalues

As far as I know, the momentum operator is as follows:



-iħ(∂/∂x)



Now lets say that I enact this operator on the famous solution to the 1-D particle in a box example:



Ψ= squrt(2/L) sin(πnx/L)



If the momentum operator operates on the above wave function, it yields:



-iħ * squrt(2/L) * (πn/L) *...



momentum operator eigenstates/eigenvalues

momentum operator eigenstates/eigenvalues