Equation Icon  ⟨ ⟩ 2 ( ) ( ) dJz- ∑ m-|Z-ℓm-ωn|- ∑ dJz- ∑ m-- dE- dt = 4πω3n ≡ dt = ωn dt . (49 ) ℓ,m,n ℓ,m,n ℓmn ℓ,m,n ℓmn