2. Main constants of atomic spectra

The main constants commonly used are listed here. These data are compiled by the National Bureau of Standards [24] a. Data are now available in computerized form [24] b ; this database includes :

• electronic data: atomic mass, spectral term and ground-state configuration, ionization potentials for the neutral atom and the first 4 degrees of ionization for the ion;

• nuclear data: atomic mass (Z + N ), isotopic abundance, nuclear spin, magnetic dipole moments and electrical quadrupoles (unfortunately, these databases are still incomplete).