Rydberg constant

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In spectroscopy, the Rydberg constant, symbol R ∞ {\displaystyle R_{\infty }} for heavy atoms or R H {\displaystyle R_{\text{H}}} for hydrogen, named after the Swedish physicist Johannes Rydberg, is a physical constant relating to the electromagnetic spectra of an atom. The constant first arose as an empirical fitting parameter in the Rydberg formula for the hydrogen spectral series, but Niels Bohr later showed that its value could be calculated from more fundamental constants according to his model of the atom. Before the 2019 revision of the SI, R ∞ {\displaystyle R_{\infty }} and the electron spin g-factor were the most accurately measured physical constants. The constant is expressed for either...

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