Using the infinitesimal rotation operator and its Hermitian conjugate, one can derive the commutation relation in the spherical basis: [ J a , T ^ ^ q ( 2 ) ] = ∑ ∑ q ′ D ( J a ) q q ′ ( 2 ) T ^ ^ q ′ ( 2 ) = ∑ ∑ q ′ ⟨ ⟨ j = 2 , m = q | J a | j = 2 , m = q ′ ⟩ ⟩ T ^ ^ q ′ ( 2 ) and the finite rotation transformation in the spherical basis can be verified: U ( R ) † † T ^ ^ q ( 2 ) U ( R ) = ∑ ∑ q ′ D ( R ) q q ′ ( 2 ) ∗ ∗ T ^ ^ q ′ ( 2 )