  The yield of the isomeric state 117mSn (Eiso = 314.58 keV) has been measured
in (gamma, gamma') reaction by activation method with the bremsstrahlung
end-point energy from 2.1 to 3.0 MeV. Only one intermediate state (IS)
responsible for the isomer feeding has been found. The excitation energy of the
IS (2.25 +/- 0.05) MeV and photoproduction integral cross section (0.022 +/-
0.002) eV b have been deduced. Microscopic calculations within the
Quasiparticle-phonon model have been performed to learn on the IS structure. We
conclude that the IS is excited in the present experiment by the E3-transition.
