Using the Brink-Axel hypothesis we derive the rate R for nuclear dipole excitation by a laser pulse carrying N≫1 photons with average energy ℏω0≈5 MeV. As expected R∝(ℏω0)3. The rate is also proportional to the aperture α of the laser pulse. Perhaps less expected is the fact that R∝N, irrespective of the degree of coherence of the laser pulse. The expression for R, derived for a nearly stationary laser pulse, is valid also for short times and can, thus, be used in simulations via rate equations of multiple nuclear dipole excitations by a single pulse. The explicit dependence of R on the parameters of the laser pulse and on nuclear parameters given in the paper should help to optimize experiments on laser-nucleus reactions.
A. Pálffy, P.-G. Reinhard, H. A. Weidenmüller: Rate for Laser-Induced Nuclear Dipole Absorption, Phys. Rev. C 101, 034619 (2020), (DOI: 10.1103/PhysRevC.101.034619)
Related to Project B02