Laser-assisted internal conversion

A general formula for the coefficient of internal conversion in an intense laser field, which is valid for all atomic electron shells, is deduced in a simple nonrelativistic model. For special shells, for which internal conversion without the laser is energetically forbidden but which have an energy defect relatively small compared to the laser photon energy, the presence of the laser radiation is essential. Cases such as the 4s(1/2 shell internal conversion of the E1 transition of the isomeric state ¹⁸³Wᵐ (E_γ=544 eV, {τ}=5.3 s, J=(11/2⁺) and the 5d(3/2, 5d(5/2 shell internal conversions of the E3 transition of the isomeric state ²³⁵Uᵐ (E_γ=73.5 eV, {τ}=26 min, J=(1/2⁺) are numerically investigated in the small momentum approximation.