This compilation revises the 1991 listing of atomic data for the lighter elements from hydrogen to gallium. The tabulation emphasizes resonance lines, i.e., lines whose lower level is the ground state, or an excited fine-structure state of the ground term, and is restricted to wavelengths longward of the H I Lyman limit at 911.753 ?. All but the very weakest known and predicted electric-dipole transitions are included, but no forbidden lines. This paper has attempted to review all data published by the end of 2002.?????The tables contain the best data available to the author on ionization potentials, level designations, vacuum and air wavelengths, lower and upper energy levels, statistical weights, transition probabilities, natural damping constants (reciprocal lifetimes), oscillator strengths, and the often used combinations of log gf and log ?f. All ion stages with relevant classified lines are included. Individual components resulting from isotope shift and hyperfine structure are listed explicitly for certain species. The accompanying text provides references, explanations for the critical selection of data, and notes indicating where new measurements or calculations are needed.?????This compilation should be particularly useful in the analysis of interstellar and quasar absorption lines and other astrophysical sites where the density of particles and radiation is low enough to excite only the lowest atomic levels. The data also are relevant to the study of stellar atmospheres, and gaseous nebulae.?????An Appendix summarizes new data relevant to the similar compilation in Paper II for the elements germanium to uranium.

https://iopscience.iop.org/article/10.1086/377639/pdf

Atomic Data for Resonance Absorption Lines. III. Wavelengths Longward of the Lyman Limit for the Elements Hydrogen to Gallium

Correlation consistent basis sets of double-ζ through quintuple-ζ quality for the alkali and alkaline earth metals Li, Be, Na, and Mg have been developed, including the valence (cc-pVnZ), augmented valence (aug-cc-pVnZ), core-valence (cc-pCVnZ), and weighted core-valence (cc-pwCVnZ) basis sets. The basis sets are also re-contracted for Douglas–Kroll scalar relativistic calculations and are found to be superior to non-relativistic basis sets in recovering scalar relativistic effects. CCSD(T) computations have been performed with these basis sets, and a series of properties have been examined, including atomic ionization potentials and electron affinities, optimized molecular geometries, harmonic vibrational frequencies, atomization energies, and enthalpies of formation for the molecules Li2, LiF, BeO, BeF, BeH2, BeF2, Na2, NaF, MgO, MgF, MgH2, and MgF2.

Gaussian basis sets for use in correlated molecular calculations. VII. Valence, core-valence, and scalar relativistic basis sets for Li, Be, Na, and Mg

▪ Abstract Low-mass particles, such as neutrinos, axions, other Nambu-Goldstone bosons, and gravitons, are produced in the hot and dense interior of stars. Therefore, astrophysical arguments constrain the properties of these particles in ways that are often complementary to cosmological arguments and to laboratory experiments. This review provides an update on the most important stellar-evolution limits and discusses them in the context of other information from cosmology and laboratory experiments.

Particle physics from stars

A comprehensive review is given on photoionization of rare gas atoms using monochromatized synchrotron radiation. Emphasis is put upon the general experimental and theoretical background, and illustrative examples are presented in order to show the present status and the progress in the field during the last decade.

https://iopscience.iop.org/article/10.1088/0034-4885/55/9/003/pdf

Photoionization of atoms using synchrotron radiation

Molecular-beam experiments have exposed a new wealth of detail on the general reaction ${A}^{*}+B\ensuremath{\rightarrow}A+{B}^{+}+{e}^{\ensuremath{-}}$ first suggested by Penning in 1927. The new capabilities not available to traditional swarm techniques include mass and electron spectroscopy on the reaction products and angle-resolved measurements of the scattering of both reagents and products. These new results have stimulated the recent development of both the electronic structure and the dynamical theories necessary for a first-principles description of at least the simplest of these reactions, those involving small atomic and diatomic species $B$. Recent progress in both experiment and interpretation is critically reviewed, and the prospects for attaining a global understanding of Penning ionization in larger systems are assessed.

Molecular-beam studies of Penning ionization

A method of simultaneously determining the magnitude of the cross section for photoionization of an excited atom and the atomic density of the ground state is presented. Measurements of $\ensuremath{\sigma}$ for $\mathrm{Ba}(6s6p^{1}P_{1})$, $\mathrm{K}(4p)$, and $\mathrm{Na}(3p)$ at photon ionizing energy 3.51 eV (3533 \AA{}) are reported and compared with previous values. Application of this technique to the determination of the density in an atomic beam is discussed.

Absolute measurement of photoionization cross sections of excited atoms: Application to determination of atomic beam densities.

Absolute photoionization cross sections for the 6s6p 1 P excited state of Ba have been measured in the threshold region and found to agree substantially with theory, thus resolving previous discrepancies. Use was made of the «magic» angle applied to the relative orientation of the linear polarizations of the exciting and ionizing lasers; at this orientation angle the measured cross section is the same as if the excited state were populated isotropically

Absolute cross sections for the photoionization of the 6s6p 1P excited state of barium.

The properties of Rydberg atoms are contrasted with those of hydrogen atoms using both classical and quantal points of view. It is shown that, classically, the effects of the ionic core of the Rydberg atom produce a precession of the otherwise Keplerian elliptical orbit of the excited electron, and that this precession is responsible for the nonhydrogenic properties. Using the correspondence principle, classical properties are then related to quantum mechanical properties by correlating the precession frequency with the quantum defect δl. The linear and quadratic Stark effects are also discussed and it is shown that a negative polarizability of the atom is a consequence of a positive ∂δl/∂l. In the Appendix, the ‘‘gravitational defect’’ associated with the precession of the perihelion of the Keplerian orbit of the planet Mercury is presented.

Classical view of the properties of Rydberg atoms: Application of the correspondence principle

The observation of structure in the photoionization cross section of magnesium in the vicinity of the $3s$ threshold is reported. The structure is the result of simultaneous (single photon) two-electron excitation followed by autoionization. The data are in excellent agreement with theory.

Photoionization of magnesium near threshold

Measurements of the cross section for photoionization of the excited $3p$ state of sodium have been made over a significant energy range. Calculations at the central-field and Hartree-Fock levels have also been carried out. Agreement between theory and experiment is excellent.

Charles E. Burkhardt

Papers

Absolute measurement of photoionization cross sections of excited atoms: Application to determination of atomic beam densities.

Absolute cross sections for the photoionization of the 6s6p 1P excited state of barium.

Classical view of the properties of Rydberg atoms: Application of the correspondence principle

Photoionization of magnesium near threshold

Photoionization of the excited 3p state of sodium: Experiment and theory.