Induced emission ofγradiation from isomeric nuclei

We study the possibility to influence the lifetime of nuclear isomeric states with the aid of incident fluxes of photons. We assume that a nucleus initially in an isomeric state $|i〉$ first absorbs an incident photon of energy $E_{\mathrm{ni}}$ to reach a higher intermediate state $|n〉$ and then the state $|n〉$ decays to a lower state $|l〉.$ In favorable cases the two-step induced emission rates become equal to the natural isomeric decay rates for incident power densities of the order of ${10}^{10}$ W cm${}^{-2}.$