What Are Ritz Wavelengths in the NIST Atomic Spectra Database?

[lil1xal]

Hello all,

What is mean the Ritz Wavelengths in the NIST Atomic Spectra Database?

Why the Ritz or Observed value for some Wavelength are very different?

Thanks,
Lil

 

[Hypersphere]

See http://physics.nist.gov/PhysRefData/ASD/Html/lineshelp.html#OUTWAVELENGTH

The Ritz wavelengths are calculated from the difference in the energy levels involved in the transition, whereas the observed values are the experimental data. The accuracy of the Ritz wavelengths obviously depends on the accuracy of the calculated energy levels, and the accuracy of the observed values is limited by experimental precision, so some transitions can give quite different wavelengths.