We have recorded spectra of iron-neon and iron-argon hollow cathode lamps in the region 1700Å -5 µm (59 000 -2000 cm −1 ), with Fourier transform (FT) spectrometers at the National Solar Observatory, Tucson, Arizona, U.S.A. and Imperial College, London, U.K., and with a high resolution grating spectrograph at the National Institute of Standards and Technology, Gaithersburg, U.S.A. The uncertainty of the strongest lines in the FT spectra is <0.002 cm −1 (0.2 mÅ at 3000Å; 8 mÅ at 2 µm ). Pressure and current-dependent shifts are <0.001 cm −1 for transitions between low lying levels, increasing to 0.006 cm −1 for transitions between the most highly excited levels. We report 28 new energy levels of Fe I and revised values of another 818 levels. We have identified 9501 lines as due to 9759 transitions in Fe I, and these are presented in the form of a new multiplet table and finding list. This compares with the ∼5500 lines due to 467 energy levels in the multiplet tables of Moore (1950, 1959). The biggest increase is in the near ultraviolet and near infra-red, and many of the new lines are present in the solar spectrum. Experimental log(gf) values are included where they are available. A further 125 unidentified lines due to Fe I are given. The tables are also available in computer-readable form.

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Following a critical review of spectroscopic data for neutral strontium ͑Z=38͒, the energy levels, with designations and uncertainties, have been tabulated. Wavelengths with classifications, intensities, and transition probabilities have also been reviewed. In addition, the 5s 2 S 1/2 , 4d 2 D 3/2 , and 4d 2 D 5/2 ionization energies have been listed. A summary of the current state of measurements of the Sr I 5s 2 1 S 0-5s5p 3 P 0 ‫ؠ‬ , F =9/ 2 atomic clock transition, and other isotopic observations has also been included.

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