# Rydberg constant

The

**rydberg constant** is named after

physicist Janne Rydberg, and is a

physical constant discovered when measuring the

spectrum of

hydrogen, and building upon results from

Anders Jonas Ångström and Johann Balmer. Each

chemical element has it's own Rydberg constant, but most commonly referred to is the "infinity" constant.

The "infinity" Rydberg constant is:

The "infinity" constant appears in the formula:

Which gives the Rydberg constant for a certain

atom with one

electron with the

rest mass and the

atomic nucleus mass . And can be derived from the formula:

As the formula for the Rydberg constant contains no less than

*five* other

physical constants, namely the

elementary charge , the

electron rest mass , the

permittivity of vacuum ,

Planck's constant , and the

speed of light in

vacuum , it is one of the most well-determined physical constants. Measuring the Rydberg constant namely confirms the proportions of the values of the other five constants.

For more information about this formula, see the article on the Rydberg formula.