Rydberg constant

The Rydberg constant (R_H) is the constant used in the Rydberg formula for neutral atomic hydrogen spectral-line wavelengths:

1/λ = RH( 1/m² - 1/n² )

• R_H is the Rydberg constant for hydrogen, approximately 1.0973731568157 × 10⁷m^-1, which is roughly "13.6 eV / (hc)".
• m - number of lower energy orbit.
• n - number of higher energy orbit.
• h - Planck constant.
• c - speed of light in a vacuum.

With slightly different Rydberg constants, the same formula is valid for neutral atomic deuterium, as well as other elements ionized to the point of having a single electron (e.g., singly-ionized helium). The corresponding constants have names such as Rydberg constant for deuterium (R_D).