This database provides theoretical values of energy levels of hydrogen and deuterium for principle quantum numbers n = 1 to 200 and all allowed orbital angular momenta l and total angular momenta j. The values are based on current knowledge of the revelant theoretical contributions including relativistic, quantum electrodynamic, recoil, and nuclear size effects. Hyperfine structure effects are not included. Contributions that are only known for low n states have been extrapolated to highly-excited states. Fundamental constants used in the calculations are taken from the CODATA 2002 least-squares adjustment and can be found at the NIST Fundamental Physical Constants Web site. The changes that would result from using the most recent CODATA recommended values of the fundamental constants are insignificant for the theoretical predictions. Quoted uncertainties take into account uncertainties in the theoretical calculations, uncertainties in the fundamental constants, and covariances between the various contributions and input parameters.
This interactive database allows a user to obtain individual energy levels and transition frequencies as well as tables of frequencies. Given the volume of the possible data, this Web site is designed to calculate the values on request.
NIST Standard Reference Database 142 | Customer Support | Online: May 2004 | Last update: July 2005