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Narrow dips were found in the excitation spectra of crystals of alkaline earth fluorides doped with ErF3 or/and YbF3. The positions of the dips are in good agreement with the positions of the narrow absorption lines Er3+, Yb3+ measured earlier. The absorption lines of the crystals were calculated from the excitation spectra. The observed dips in the excitation spectra are due to the absorption lin
