Information

Most entries on the individual scheme pages should be fairly self-explanatory. Below a few additional notes on some special features.

Ionization potentials

Ionization potentials (IPs) are given on overview pages and on the individual scheme pages. All of the IPs have a reference with a given year. Most IPs are taken from these two databases:

• NIST Atomic Spectra Database (NIST ASD)
• Grotrian

In these cases, the years given in parentheses are the years when the databases were last accessed.

To report a better IP value, please raise an issue or get in touch with a maintainer.

Saturation curve fits

All saturation curves (where wanted) are fit with a first-rate model (Letokhov, 1987). In brief, the saturation curve is fit with the equation:

\[N = N_i + N_{max} \cdot \left[1 - \exp \left(- \frac{I}{I_{sat}}\right)\right]\]

Here \(N\) is the measured signal, \(N_i\) the measured signal at zero irradiance, \(N_{max}\) the maximum signal, \(I\) the laser irradiance, and \(I_{sat}\) the saturation irradiance of the transition. While this model does not describe real multilevel transitions, it provides a semi-quantitative measure of the effectiveness of the schemes.

Schemes with maximum wavelength for ionization transition

In some cases, the ionization transition is not to a specific autoionizing or Rydberg state, but rather to the IP. In these cases, the transition is indicated with a maximum wavelength and the transition arrow in the scheme diagram is hollow. This is to indicate that the exact final state is not known.