Rydberg constant

Atomic fundamental physical constant $R ∞ = E h 2 h c 0 = 1.097 373 1534 13 × 10 7 m −1$ , where $E h$ is the Hartree energy, $h$ the Planck constant, and $c 0$ the speed of light.

Source:

CODATA Bull. 1986, 63, 1