The γ -ray emission from the nuclei 62,64 Fe following Coulomb excitation at bombarding energy of 400-
440 AMeV was measured with special focus on E1 transitions in the energy region 4-8 MeV. The
unstable neutron-rich nuclei 62,64 Fe were produced at the FAIR-GSI laboratories and selected with the
FRS spectrometer. The γ decay was detected with AGATA HPGE tracking array. From the measured γ -ray spectra the summed
E1 strength is extracted and compared to microscopic quasi-particle phonon model calculations. The
trend of the E1 strength with increasing neutron number is found to be fairly well reproduced with
calculations that assume a rather complex structure of the 1− states (three-phonon states) inducing a
strong fragmentation of the E1 nuclear response below the neutron binding energy.