Recommendation 3 of the 94th CIPM (2005)

Revision of the Mise en pratique list of recommended radiations

The International Committee for Weights and Measures (CIPM),

considering that:

• improved frequency values for radiations of some high-stability cold ion and cold atom standards already documented in the recommended radiations list have recently become available;
• improved frequency values for the infra-red gas-cell-based optical frequency standard in the optical telecommunications region, already documented in the recommended radiations list, have been determined;
• improved frequency values for certain iodine gas-cell standard, already documented in the subsidiary recommended source list, have been determined;
• frequencies of new cold atoms, of atoms in the near-infrared region and of molecules in the optical telecommunications region have been determined by femtosecond comb-based frequency measurements for the first time;

decides that the list of recommended radiations be revised to include the following:

• updated frequency values for the single trapped ⁸⁸Sr⁺ ion quadrupole transition, the single trapped ¹⁹⁹Hg⁺ quadrupole transition and the single trapped ¹⁷¹Yb⁺ quadrupole transition;
• an updated frequency value for the Ca atom transition;
• an updated frequency value for the C₂H₂-stabilized standard at 1.54 µ
• an updated frequency value for the I₂-stabilized standard at 515 nm;
• the addition of the ⁸⁷   Sr atom transition at 698 nm;
• the addition of the ⁸⁷  Rb atom two-photon transitions at 760 nm;
• the addition of the ¹²C₂H₂ (ν1 + ν3) band and the ¹³C₂H₂ (ν1 + ν3) and (ν1 + ν3 + ν4 + ν5) bands at 1.54 µm.

DOI : 10.59161/CIPM2005REC3E