  New reference wavelengths for atomic transitions of Mg VII and Si VII in the
272-281 A wavelength range are derived using measurements from the Extreme
ultraviolet Imaging Spectrometer (EIS) on board the Hinode spacecraft. Mg VII
and Si VII are important ions for measuring plasma properties in the solar
transition region at around 0.6 MK. The six Si VII wavelengths are 13--21 mA
and 7--11 mA longer than the values in the NIST Atomic Spectra Database (ASD)
and the compilations of B. Edlen, respectively. The four Mg VII wavelengths are
shorter than the values in the ASD by 8-12 mA but show reasonable agreement
with the Edlen values. The new wavelengths will lead to more accurate Doppler
shift measurements from the EIS instrument, and will be valuable for spectral
disambiguation modeling for the upcoming Multi-Slit Solar Explorer mission.
