Theory paper on laser-induced de-excitation of the isomer

The exact energy of the isomer is still unknown, but there is good news: the recent experiments at LMU in Munich have shown that a 2 percent fraction of U-233 recoil ions are in the isomeric state. Such ions can now be used for spectroscopy. In a recent publication, researchers from MPIK in Heidelberg and PTB in Braunschweig suggest a new approach to measure the isomer energy. In a so-called LIEB process (laser-induced electron bridge), an electron combines the energy of the isomer together with the energy of a photon of the excitation laser to resonantly populate an excited electronic state. From here, it may decay down again into a lower electronic state. Such laser-assisted excitation increases the nuclear decay rate by orders of magnitude. The manuscript is now available here on the arXiv.