Recommendation 1 of the 96th CIPM (2007)

Revision of the Mise en pratique list of recommended radiations

The International Committee for Weights and Measures,

considering that:

• improved frequency values of molecules in the optical telecommunications region, already documented in the list of standard frequencies, have been determined by femtosecond comb-based frequency measurements;
• frequencies of molecules in the optical telecommunications region have been determined by femtosecond comb-based frequency measurements for the first time;
• frequencies of certain iodine gas-cell absorptions close to the 532 nm optical frequency standard have been determined by femtosecond comb-based frequency measurements for the first time;

proposes that the list of standard frequencies be revised to include the following:

• an updated list of frequency values for the ¹²C₂H₂ (ν1 + ν3) band at 1.54 µm;
• the addition of frequency values for the ¹²C₂HD (2ν₁) band at 1.54 µm;
• the addition of frequency values for the hyperfine components of the P(142) 37-0, R(121) 35-0 and R(85) 33-0 iodine transitions at 532 nm.

DOI : 10.59161/CIPM2007REC1E