The vacuum wavelengths of 27 lines of Hg198 and 6 lines of Kr86 have been measured relative to the international standard of length, the Kr86 line at 6057.80211 Å, by photographic Fabry–Perot interferometry. These measurements were made with Hg198 electrodeless lamps containing argon at pressures of
, 3, and 10 mm Hg and a Kr86 hot-cathode lamp operated according to the conditions prescribed by the International Conference on Weights and Measures in 1960. Energy-level values have been derived from the wavelengths of each of the Hg198 sources, and on the basis of these values, the energy level and wavelength shifts per unit pressure of argon have been calculated. The suitability of the Hg198 electrodeless lamp as a source of wavelength standards for interferometric measurement of length and wavelength is discussed.
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Δ3 = |λ3obs − λ3calc| Å.
This is given in units of Å per mm Hg.
Indicates that this is the only line used to evaluate the even level involved.
Indicates that this line was not measured but was calculated from the known levels involved.
Indicates that this line was neither measured nor calculated.
Indicates that a pressure shift could not be calculated for this line.
All wave numbers and energy levels are in units of cm−1.
These wave numbers have not been observed but have been calculated.
The first number indicates the energy level for the
mm Hg source.
The second number indicates the energy level for the 3 mm Hg source.
The third number indicates the energy level for the 10 mm Hg source.
Δ3 = |λ3obs − λ3calc| Å.
This is given in units of Å per mm Hg.
Indicates that this is the only line used to evaluate the even level involved.
Indicates that this line was not measured but was calculated from the known levels involved.
Indicates that this line was neither measured nor calculated.
Indicates that a pressure shift could not be calculated for this line.
All wave numbers and energy levels are in units of cm−1.
These wave numbers have not been observed but have been calculated.
The first number indicates the energy level for the
mm Hg source.
The second number indicates the energy level for the 3 mm Hg source.
The third number indicates the energy level for the 10 mm Hg source.