Atomic Level Shifts Research Articles

The determination of energy-level shifts which accompany chemisorption

Considerable confusion exists concerning a reasonable procedure for determining energy shifts of atomic levels on adsorption of a free gas atom to a solid surface and concerning the basic concepts involved. This paper discusses the ionization limit with respect to which energy levels of the adsorbed complex should be referenced, how this limit may be defined and what the best method is for determining its energy level. It is also demonstrated that one cannot sidestep the determination of the ionization limit by measuring in the same apparatus the kinetic energies of electrons ejected from the free atom and from the adsorbed atom.

Direct Observation of Atomic Energy Level Shifts in Two-Photon Absorption.

We report direct observation of optically induced shifts of atomic energy levels in sodium vapor that occur in two-photon absorption. These shifts must be considered in high-resolution two-photon spectroscopy. Two cw dye laser beams of different frequencies and propagating in opposite directions are utilized to obtain high-resolution spectra. The intensity and frequency dependence of the level shifts are examined.

Direct Observation of Atomic Energy Level Shifts in Two-Photon Absorption

We report direct observation of optically induced shifts of atomic energy levels in sodium vapor that occur in two-photon absorption. These shifts must be considered in high-resolution two-photon spectroscopy. Two cw dye laser beams of different frequencies and propagating in opposite directions are utilized to obtain high-resolution spectra. The intensity and frequency dependence of the level shifts are examined.

Strong-interaction effects in antiprotonic atoms

A $\overline{p}$-nucleus potential is constructed by folding a $\overline{p}N$ potential in the nuclear matter density. The strength of the $\overline{p}N$ potential is adjusted to the corresponding scattering lengths. The resulting $\overline{p}$-nucleus force consistently reproduces the antiprotonic atoms level shifts and widths.

Kaon-nucleus interaction at low energies

A kaon-nucleus absorptive potential is derived by folding the $\overline{K}N$ finite range complex potential into the nuclear density distribution. The strengths of the $\overline{K}p$ and $\overline{K}n$ potentials have been adjusted to the corresponding scattering length values and the range of the $\overline{K}N$ forces has been obtained by fitting the $\overline{K}\ensuremath{-}^{4}\mathrm{He}$ scattering data. The resulting $\overline{K}N$ potential with no free parameters has been used to calculate kaonic atom level shifts and widths. Within the experimental uncertainties all kaonic data can be fitted in a consistent manner.

Effects of retardation on electromagnetic self-energy of atomic states

The significance of retardation effects in photon emissions and absorption is emphasized in the calculation of self-energy. It is explicitly demonstrated that inclusion of such effects leads to a finite answer for the shifts of atomic energy levels in a nonrelativistic theory without cutoff. Ambiguities that exist in the mass renormalization in the non-relativistic approach are pointed out. Such ambiguities vanish from the relativistic theory. Explicit calculation is carried out in the case of hydrogen by utilizing the Coulomb Green's function. The advantage of the present approach in calculating self-energy shift in high Z hydrogenic ions is suggested. (auth)

Comment on the radiative level shift in the neoclassical radiation theory

It is shown that when spin currents are included in the neoclassical radiation theory of Jaynes et al., radiative atomic level shifts are obtained which in the case of hydrogen are in strong disagreement with experiment.

Transition rates of the resonant processes in Li + and Na + ion interaction with Li, W and Mo surfaces

The transition rates of the resonant neutralization and ionization processes of Li +, Na + and Li particles interacting with Li, W and Mo surfaces are calculated using the time-dependent perturbation theory. The bound-state wave functions are taken either as the best one-parameter variational functions, or as the Hartree-Fock wave functions. The metallic electron is described properly in the framework of the Sommerfield model for the metal. The effect of the atomic level shift is taken explicitly into account in the derivation of the mean de-activation distance and in the total probability calculations of these processes.

Dipole and Quadrupole Moments of the IsomericHg197*Nucleus; Isomeric Isotope Shift

The hyperfine structures of five optical lines of 65-hour radioactive ${\mathrm{Hg}}^{197}$ and 25-hour isomeric ${\mathrm{Hg}}^{197*}$ were measured. Radioactive mercury produced by cyclotron bombardment and excited in electrodeless discharge tubes containing as few as 5\ifmmode\times\else\texttimes\fi{}${10}^{12}$ atoms, free of natural mercury, gave adequate light intensities. The analysis of the hyperfine structure confirmed the magnetic dipole moment and isotope shift of ${\mathrm{Hg}}^{197}$ in its ground state ($I=\frac{1}{2}$), and gave the following values for ${\mathrm{Hg}}^{197*}$ $(\mathrm{based}\mathrm{on}I=\frac{13}{2}):{\ensuremath{\mu}}_{{197}^{*}}=\ensuremath{-}1.04\ifmmode\pm\else\textpm\fi{}0.01$ nm; ${Q}_{{197}^{*}}=(1.5\ifmmode\pm\else\textpm\fi{}0.3)\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}24}$ ${\mathrm{cm}}^{2}$; isotope shift displacement (from ${\mathrm{Hg}}^{198}$ in the 2537 A line)+70\ifmmode\pm\else\textpm\fi{}7\ifmmode\times\else\texttimes\fi{}${10}^{\ensuremath{-}3}$ ${\mathrm{cm}}^{\ensuremath{-}1}$. Thus an isomeric shift of atomic energy levels resulting from the excitation of the nucleus from its ground state $I=\frac{1}{2}$ to the isomeric state $I=\frac{13}{2}$ is observed. In the 2537 A line of mercury this shift amounts to -21\ifmmode\pm\else\textpm\fi{}6\ifmmode\times\else\texttimes\fi{}${10}^{\ensuremath{-}3}$ ${\mathrm{cm}}^{\ensuremath{-}1}$.