W. C. Martin

Energy levels of magnesium, Mg I through Mg XII

Energy level data are given for the atom and all positive ions of magnesium (Z=12). These data have been critically compiled, mainly from published material on measurements and analyses of the optical spectra. We have derived or recalculated the levels for a number of the ions. In addition to the level value in cm−1 and the parity, the J value and the configuration and term assignments are listed if known. Leading percentages from the calculated eigenvectors are tabulated wherever available. Ionization energies are given for all spectra.

Energy Levels of Silicon, Si I through Si XIV

Energy level data are given for the atom and all positive ions of silicon (Z=14). These data have been critically compiled, mainly from published material on measurements and analyses of the optical spectra. We have derived or recalculated the levels for a number of the ions. In addition to the level value in cm−1 and the parity, the J value and the configuration and term assignments are listed if known. Leading percentages from the calculated eigenvectors are tabulated or quoted wherever available. Ionization energies are given for all spectra. Key words: atomic energy levels; atomic ions; atomic spectra; electron configurations; ionization potentials; silicon.

Ground Levels and Ionization Potentials for Lanthanide and Actinide Atoms and Ions

Values of the first four ionization potentials of the lanthanides (Z=57–71) and of Hf have been compiled. All except the value for neutral Hf are based on spectroscopic data. The spectroscopic designations of the ground levels of the neutral through triply ionized atoms (Z=57–72) are also tabulated. A similar compilation for the actinides (Z=89–103) lists Sugars recent values for the first ionization potentials through No (Z=102). Accurate spectroscopic ionization potentials have been determined for only two of the actinide ions (Ac+ and Th3+). The ground‐level designations for the neutral through triply ionized actinides are given where they are known or can be predicted with near certainty. A selection of references to the most complete and most recent work on the analyses of the optical spectra of the neutral through triply ionized lanthanide and actinide elements is included.

Energy Levels of Sulfur, S I Through S XVI

Energy level data are given for the atom and all positive ions of sulfur (Z=16). These data have been critically compiled, mainly from published and unpublished material on measurements and analyses of the optical spectra. We have derived or recalculated the levels for a number of the ions. In addition to the level values in cm−1 and the parity, the J value and the configuration and term assignments are listed if known. Leading percentages from the calculated eigenvectors are tabulated or quoted wherever available. Ionization energies are given for all spectra.

Energy Levels of Neutral Helium (4He I)

This compilation of all identified levels is based on the most accurate available observations. It includes 48 levels above the He II 12S limit (two‐electron excitation).

Energy levels of phosphorus, P I through P XV

Energy level data are given for the atom and all positive ions of phosphorus (Z=15). These data have been critically compiled, mainly from published and unpublished material on measurements and analyses of the optical spectra. We have derived or recalculated the levels for a number of the ions. In addition to the level values in cm−1 and the parity, the J value and the configuration and term assignments are listed if known. Leading percentages from the calculated eigenvectors are tabulated or quoted wherever available. Ionization energies are given for all spectra.

Energy levels of aluminum, Al I through Al XIII

Energy level data are given for the atom and all positive ions of aluminum (z=13). These data have been critically compiled, mainly from published material on measurements and analyses of the optical spectra. We have derived or recalculated the levels for a number of the ions. In addition to the level value in cm−1 and the parity, the J value and the configuration and term assignments are listed if known. Leading percentages from the calculated eigenvectors are tabulated wherever available. Ionization energies are given for all spectra.

Energy levels of sodium Na I through Na XI

Energy level data are given for the atom and all positive ions of sodium (Z = 11). These data have been critically compiled, mainly from published material on measurements and analyses of the optical spectra. We have derived or recalculated the levels for a number of the ions. In addition to the level value in cm−1 and the parity, the J value and the configuration and term assignments are listed if known. Leading percentages from the calculated eigenvectors are tabulated wherever available. Ionization energies are given for all spectra.

New NIST Atomic Spectra Database

A new database has been created that makes a wealth of information on spectra, energy levels, and transition probabilities for atoms and atomic ions easily available via the World Wide Web. These data will be a valuable resource for interpretation of solar and other astrophysical spectra obtained from ground-based and space observations.

Classifications of the resonance lines of europium III

A first analysis of Eu III by Russell et al, in 1941 yielded classifications of seven lines (2350-2523 A) as transitions from the 4f/sup 78/S/ sup 0//sub 7,2/ ground level to upper levels identified only as belo nging to the 4f/sup 6/ 5d configuration. We have diagonalized a truncated energy matrix for 4f/sup 6/(/sup 7/F)5d, using parameter values appropriate for Eu III. Compar ison of the results with available data for the lines allows identifications of the seven experimental upper levels. These show that the seven lines include the three lines of the basic 4f/sup 7/ /sup 8/S/sup 0/-4f/sup 6/(/sup 7/ F)5d /sup 8/ P multiplet, the strongest resonance lines of Eu III, and account for most of the oscillator strength of the 4f/sup 7/ /sup 8/S/sup o/-4f/sup 6/ 5d group. (auth)