A nonrelativistic particle of charge e and mass m is bound by a linear, isotropic, restoring force with force constant mw20. Using (6.13) and (16.16) of Section 16.2, show that the energy and angular momentum of the particle both decrease exponentially from their initial values as e–Gt, where ?? = w20I?. Quantum mechanically, the mean excitation energy of an oscillator decays in exactly the same way because the total radiative transition probability for a state with quantum numbers n0, I0 is G(n0, I0) = n0??. The decay of the angular momentum approaches the classical law only for I0 >> 1.