The Rydberg is a unit of energy defined in terms of the ground-state energy of an electron in the Bohr model for the hydrogen atom,
in cgs, where is the electron mass, e is the charge on the electron, is h-bar, Z is the atomic number, and n is the principal quantum number for a given electron state, as
where eV denotes an electron volt. The Rydberg is implemented in Mathematica as Rydberg in the Mathematica add-on package Miscellaneous`Units` (which can be loaded with the command <<Miscellaneous`).
Bohr Model, Rydberg Constant, Rydberg Frequency, Hydrogen Atom
