  In ultraperipheral collisions (UPC) of nuclei the impact of
Lorentz-contracted electromagnetic fields of collision partners leads to their
excitations. In case of heavy nuclei the emission of neutrons is a main
deexcitation channel and forward neutrons emitted in UPC were detected at the
Relativistic Heavy-Ion Collider (RHIC) and at the Large Hadron Collider (LHC)
by means of Zero Degree Calorimeters. However, the excitation of low-lying
discrete nuclear states is also possible in UPC below the neutron separation
energy. In this work by means of the Weizsacker-Williams method the data on
nuclear resonance fluorescence (NRF) induced by real photons in 208 Pb are used
to model the excitations of discrete levels in colliding nuclei. Due to Lorentz
boosts one can expect that deexcitation photons with energies up to 40 GeV and
300 GeV are emitted in very forward direction, respectively, at the LHC and at
the Future Circular Collider (FCC-hh). Energy, rapidity and angular
distributions of such photons are calculated in the laboratory system, which
can be used for monitoring of collider luminosity or triggering particle
production in UPC.
