commutator practise chemical Engineering

posting it 2nd time answer using relevant equations

Evaluate the commutator (Pz, (P2, H]] where pz is the x-component of the momentum operator and H = + V (n) is the p? 2 + Hamiltonian of the system. - 2m. Use this result to prove the following sum rule: 12 (En Em)|(n|pz|m)| Cmy ( 1 ) av m 2 where ) and (m) are eigenvectors of H with eigenvalues En and Em, respectively