Recently, I was solving some questions on Rigid Rotor. I found this question very amusing.
Evaluate the integral
<Y(l,m+2) | Lx2 | Y(l,m+2) >
I evaluated it , value is
But I didn't get the point of evaluating it. Is there any application of such kind of integrals?
Is there any physical significance of it?
I know similar kind of integral are evaluated in case of transition dipole integral, where we take two different wave functions.
What is actual significance of such operations ?