The frequencies of four ${}_{}{}^{130}{}_{}{}^{}\mathrm{Te}_2^{}{}_{}{}^{}$ transitions at 486 nm, which are of interest as references in precision measurements of the 1S-2S transitions in hydrogen, deuterium, and positronium, are determined with an accuracy of 1 part in ${10}^9$ by interferometric comparison with ${}_{}{}^{127}{}_{}{}^{}\mathrm{I}_2^{}{}_{}{}^{}$ standard transitions.

• Received 15 November 1989

DOI:https://doi.org/10.1103/PhysRevA.41.4632