Precise frequency measurement of the 2S-8S/8Dtranstions in atomic hydrogen: New determination of the Rydberg constant

We have measured the Rydberg constant by frequency comparison of the three transitions 2S 1/2 -8S 1/2 , 2S 1/2 -8D 3/2 , and 2S 1/2 -8D 5/2 in hydrogen with the difference of two optical standards, the methane-stabilized He-Ne laser and the iodine-stabilized He-Ne laser. The frequency of the iodine-stabilized He-Ne laser has been remeasured. The new value for the Rydberg constant, R ∞=109 737.315 6830(31) cm -1 , is currently the most precise available