A total of about 240 spectral lines of <sup>86</sup>Kr I has been measured interferometrically during the past decade. Some have been measured in only one laboratory while others have been measured in as many as 12. On the whole, the agreement is good, but some discrepancies appear. For this work, almost all of the wavelengths have been averaged and used for the determination of a best set of energy-level values for this isotope of krypton. Forty-five even and 66 odd levels have been calculated by the method of least squares, with uncertainties ranging from ±0.0001 to ±0.0016 cm<sup>-1</sup>. These interferometrically determined levels have, in turn, been used to calculate a completely consistent set of wavelengths that are preferable to any single set of measurements or averages of measurements of <sup>86</sup>Kr I. The list of 530 lines contains only those calculable transitions that have been observed from krypton sources in the spectral region 3300–40 700 Å. With the exception of a number of weak lines and some close pairs, the final list of wavelengths is recommended for consideration for adoption as secondary standards.
VICTOR KAUFMAN and CURTIS J. HUMPHREYS, "Accurate Energy Levels and Calculated Wavelengths of 86Kr I," J. Opt. Soc. Am. 59, 1614-1628 (1969)