Krypton 86 radiation wavelength

In order to increase the precision of realization of the base unit meter, the definition based on the wavelength of a krypton-86 radiation was replaced in 1983 by one based on the speed of light. Also added were the prefixes zetta (Z) for 10, zepto (z) for 10 , yotta (Y) for 10 , and yocto (y) for 10 . 

This definition, adopted in 1983 by the 17th CGPM, superseded the definition based on the wavelength of a krypton-86 radiation. 

Dyakin VM, Skobelev IYu, Faenov AYa, Bartnik A, Fiedorowicz H, Szczurek M, Osterheld A, Nilsen J (1997) Precision measurements of the wavelengths of spectral lines of multiply charged krypton and argon ions formed in a gas target heated by laser radiation. Quantum Electron. 27 691-695... 

The meter is the length equal to 1650763.73 wavelengths in vacuum of the radiation corresponding to the transition between the levels 2p10 and 5ds of the krypton-86 atom. 

Photoionization studies without mass analysis (similar in principle to the first studies of homonuclear associative ionization) have recently been conducted in argon, krypton, xenon, sodium, potassium, rubidium, and cesium. The apparatus used by Huffman and Katayama is depicted in Fig. 5. The ion current reaching the collector plate and the radiation intensity incident on the photomultiplier are measured as a function of wavelength of incident radiation (from a monochromator) and pressure of gas in the cell. For purpose of reaction identification, this method is of value only in the pure gases, in which there... 

The universal standard of length is the metre, and the definition of this in terms of wavelength of light was agreed by all countries in 1960. The metre was defined at this time as 1 650763.73 wavelengths of the orange radiation of the krypton-86 isotope in vacuo. At the same time the yard was defined as 0.9144 m, which gives an exact conversion of 1 inch = 25.4mm. 

The meter (unit of length) is the length of exactly 1 650 763.73 wavelengths of the radiation in vacuum corresponding to the unperturbed transition between the levels 2p,j and Sd of the atom of krypton 86, the orange-red Une. 

One meter, m, is 1,650,763.73 wavelengths in vacuum of the orange-red radiation of the krypton-86 atom at the triple point of nitrogen (-210 C). 

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