Theoretical oscillator strengths for some transitions in P(III), As(III), Sb(III) and Bi(III)

Relativistic as well as non-relativistic oscillator strengths have been calculated for transitions in the principal sharp and diffuse series of P(III), As(III), Sb(III) and Bi(III) spectra. The radial integrals were computed by employing the wave functions obtained from a semiempirical method which included exchange effects. A comparison is presented for our calculated f_ik values with experimental and other theoretical data. The influence of relativistic effects on oscillator strengths for transitions in the P(III) through Bi(III) homologous sequence is discussed.     

Relativistic model-potential oscillator strengths and transition probabilities for 4ƒn6s−4ƒn6p transitions in Eu(II), Tb(II), and Ho(II) in J1 j coupling

The lowest $\text{4?}{}^{\mathrm{n}}\text{6s?4?}{}^{\mathrm{n}}\text{6p}$ transitions are studied for the Eu(II) (n=7), Tb(II) (n=9), and Ho(II) (n=11) spectra, where the J₁j coupling is an acceptable approximation. The relativistic radial integrals, required to evaluate the oscillator strengths and transition probabilities, are calculated with the model-potential method, which includes also core-polarization effects. The similarities observed in oscillator strengths for transitions with given ΔJ but different J values are discussed and explained. The computer oscillator strengths are compared with those obtained with the Coulomb approximation and it is found that the latter are only 11–12% lower. The core polarization influence on oscillator strengths is also investigated and the 19–21% decrease in oscillator strengths due to this effect is predicted. This result may, however, be overestimated because of some deficiencies in our procedure.     

Relativistic oscillator strengths for some transitions in Cu(I), Ag(I) and Au(I)

Relativistic oscillator strengths have been calculated for transitions in the principal, sharp and diffuse series of Cu(I), Ag(I) and Au(I) spectra. The computations have been performed by employing a semiempirical method which includes exchange and core-polarization effects. A comparison is presented for the calculated ?_ik values with experimental and other theoretical data. The influence of core-polarization effects on oscillator strengths is discussed.     

Relativistic Hartree-Fock oscillator strengths for the lowest s→p transitions in the first few members of the Rb(I) and Cs(I) isoelectronic sequences,with allowance for core polarization

Relativistic single-configuration Hartree-Fock oscillator strengths for the lowest ns²S_{$\text{1}\text{2}$}→ np²P_{$\text{1}\text{2}$,$\text{3}\text{2}$} transitions in the first few members of the rubidium (n = 5) and cesium (n = 6) isoelectronic sequences have been studied, both with and without allowance for core polarization. The effect of polarization of the core of the atom or ion by the valence electron is included by introducing a polarization potential in the one-electron Hamiltonian and by employing the corresponding correction for the dipole-moment operator in the transition matrix element. The results obtained compare well with available experimental data and indicate a significant influence of core-polarization effects on oscillator strengths. The behaviour of the oscillator strengths for the low Z part of the isoelectronic sequences is discussed.     

Relativistic Hartree-Fock energies and oscillator strengths for some ions with ns2np (n=4minus;6) ground-state configuration

The lowest s and p levels in the spectra of ions isoelectronic with gallium, indium and thallium Ge(II) through Se(IV), Sn(II) through Te(IV), Pb(II), and Bi(III) are studied using the relativistic single-configuration Hartree-Fock method. The ionization energies, fine structure intervals, sharp series line-strength ratios, and oscillator strengths are computed and compared with experiments. Deviations in line-strength ratios from statistical ratios are discussed. The influence on oscillator strengths of valence- core electron correlations (core polarization) is included within the single-configuration scheme and is investigated. It is found that, for sharp series transitions, core polarization is less important in ions isoelectronic with Ga, In, and Tl than in neutral systems and both core-polarization-corrected and uncorrected oscillator strengths agree with experiments within experimental errors. This good agreement proves that, for sharp series transitions, the relativistic single-configuration Hartree-Fock method yields acceptable results.     

Oscillator strengths for O(II) ions

Oscillator strengths between various doublet states of O(II) ions are calculated with extensive use of multi-configuration wave functions. The lower levels for the transition are in the 2p^{3 2}D⁰ and 2p^{3 2}P⁰ states, and the upper levels are 2p⁴, 3s, and 3d states. The results, which are estimated to have errors of less than 10% for individual transitions, agree quite well with beam-foil experiments, as well as with calculations made by the use of the non-closed-shell many-electron theory (NCMET). The present ratios of transition probabilities are estimated to have errors of less than 20%. A comparison with recent branching ratio measurements indicates that agreement between theory and experiment is within the overlap of the error bars except for the $\text{538}\text{581}$ Å pair. Agreement with rocket measurements is only within the overlap of the error bars for the $\text{718}\text{797}$ Å pair.     

One-electron spectrum of Lu2+: Relativistic energies,transition probabilities and dipole polarizability

Calculations are reported of relativistic model-potential ionization energies and transition probabilities in the one-electron spectrum of doubly ionized lutetium. The approach employed includes both valence-core electron exchange and correlation. The influence of polarization of the core by the valence electron on ionization energies and transition probabilities has been studied. Strong cancellation effects, similar to those found previously for the Yb(II) spectrum, have been found for higher transitions of the principal series. Energies are predicted for some states that have not yet been determined experimentally. Computed oscillator strengths for the principal series are employed to obtain a tentative value for the static dipole polarizability of the doubly-ionized lutetium ground state … 4f¹⁴6s²S_{$\text{1}\text{2}$}.     

Relativistic Hartree-Fock oscillator strengths for the lowest s→p and p→d transitions in the first few members of the Ag(I) and Au(I) isoelectronic sequences,with allowance for cope polarization

Relativistic, single-configuration Hartree-Fock oscillator strengths for the lowest ns²S_{$\text{1}\text{2}$}→np²P_{$\text{1}\text{2}$$\text{3}\text{2}$} and np²P_{$\text{1}\text{2}$$\text{3}\text{2}$}→nd²D_{$\text{3}\text{2}$$\text{5}\text{2}$} transitions in the first few members of the silver (n = 5) and gold (n = 6) isoelectronic sequences have been studied, both with and without allowance for core polarization. Core polarization is included by introducing a polarization potential in the one-electron Hamiltonian and by employing the corresponding correction for the dipole-moment operator in the transition matrix element. The results obtained are compared with available experimental data and the influence of core-polarization effects on oscillator strengths is discussed.     

类Na离子振子强度的相对论效应

 采用相对论和非相对论原子自洽场方法,计算了类Na离子（原子序数为11~92）的3s-np,3p-ns和3p-nd跃迁过程的激发能和光学振子强度;通过比较相对论与非相对论的结果,研究了M壳层电子的相对论效应随原子序数的变化规律。结果表明：对n=3的跃迁过程,相对论效应主要是影响激发能,对线强度(或跃迁矩阵元)的影响不重要;对于n>3的跃迁过程,相对论效应同时影响线强度和激发能,通常对线强度的影响更大。这些结果对惯性约束聚变和X射线激光研究中需要的不透明度参数计算有重要的参考意义。     

Conjugaisons finies et milieux continus en relativité générale

We present here the main elements of a mechanics of relativistic continua relying upon a concept of 《finite conjugacy》 between two relativistic motions described by two unit vector-fields u and u' defined on two different relativistic manifolds $\text{M}$-and $\text{M}$'.This purely relativistic, global, and intrinsic theory leads, together with a new approach of the deformation tensors in relativity, to a differential system of equations for the conjugacies which is neither under-determined nor over-determined. A rough study of the propagation of the conjugacy-waves shows then that it is advisable to consider the notion of a finite conjugacy as a satisfying relativistic extension of the classical and tridimensional notion of a finite deformation in mechanics, and to identify the spatial conjugacy-waves obtained with the ordinary acoustic waves.Drastic particularizations of the space-times $\text{M}$ and $\text{M}$', of the motions u and u', of the admissible types of conjugacies and of the elastic behaviour of the continua under study allow to recover, as very important but particular cases, the tridimensional non-relativistic theory of elasticity for finite deformations and non-linear behaviour, as well as the main theories of relativistic elasticity already proposed by Mmes Choquet-Bruhat and Lamoureux-Brousse, Rayner, Carter and Carter-Quintana, Grot-Eringen…. The obtained system of equations generalizes also to the finite case some aspects of the infinitesimal theory of Weber and Papapetrou.     

Spectra of heliumlike carbon,aluminium and argon under strongly coupled plasma

Spectral line positions for the highly stripped helium like carbon, aluminium and argon embedded in intense plasma environments have been calculated theoretically to compare with the existing data available from laser plasma experiments. The changes in the ionization potentials for such ions have been determined and the excitation energies, oscillator strengths and transition probabilities for the transitions 1s^{2 1}S → 1snp ¹P (n=2-5) have been evaluated for the diagnostic determination of such plasmas. The ion sphere (IS) model was used for estimating the effect of strongly coupled plasma on the ions within the non-relativistic as well as the relativistic framework. Time dependent perturbation theory has been applied for obtaining the linear response properties of the ions in the non-relativistic approximation. The effects of the plasma environment on such properties of the ions under the Debye screening model with suitable cut off radii have also been considered for comparing the data with those obtained from the IS model of the plasma.     

An angle-resolved photoemission study of the chemisorption of chalcogens on Cu(100): II. Cu(100) + c(2 × 2)O

Starting with the three-step direct-transition model of ARPES for bulk materials, which was examined in the preceding paper, we propose a framework for describing changes in the photoemission spectra due to chemisorption. Normal emission ARPES data for Cu(100) with a c(2 × 2)O overlayer were obtained in the photon energy range hv = 11 to 34 eV. These spectra have been compared within the proposed framework with those obtained from clean Cu(100). Changes were found in the Cu emission features which could be explained by the relaxation of momentum conservation perpendicular to the surface in the optical excitation step and by the relaxation of momentum conservation parallel to the surface in the escape step. These changes include a photon energy dependent broadening of the d-band peak and the preferential attenuation of the sharp direct-transition feature associated with the sp-band. Some evidence for a surface resonance at the top of the d-bands has been obtained. Changes in the spectrum of scattered electrons were related to modifications of evanescent final states. A 1.3 eV wide band derived from the oxygen p_x,y-orbitals was deduced from spectra obtained at normal emission and along the $\text{Γ}\text{X}$ and $\text{Γ}\text{M}$ lines of the surface Brillouin zone. On the other hand, no emission was clearly detected from the oxygen p_z-orbitals. Oxygen induced emission above the Cu d-bands was observed and attributed to antibonding states. This emission was directed towards the bulk [011] directions.     

Elastic leed intensity-energy studies of clean (001), (110) and (111) nickel surfaces

Elastic low energy electron diffraction (LEED) intensity-energy (I-E) measurements for clean (001), (110), and (111) nickel surfaces were obtained at room temperature. Surface composition was monitored by Auger spectroscopy. I-E data from 15 to 220 eV were obtained at normal incidence for the non specular beams and for the specular beams at incidence angles from 4° to 20° on the 0° and 45° azimuths of (001), on the 0° and 90° azimuths of (110), and on the 0° azimuth of (111) nickel. Normalization of the data was performed electronically during data acquisition. Intensities were calibrated with the use of a shielded, biased Faraday collector. The effects of instrumental and experimental uncertainties were examined and minimized to obtain intensities accurate to ± 15 %, energy scales accurate to ± 0.35 eV, and incident and azimuthal angles accurate to ± 0.25° and ± 1.0° respectively.All nickel surfaces have I-E spectra which are characteristic of strong multiple scattering. Angular evolution features for (001) and (110) spectra may be correlated with intraplanar resonances associated with the onset of propagating beams. Only the (001) surfaces were found to have pronounced, sharp resonance features associated with surface barrier resonances and inelastic loss processes. Kinematic analysis of the Lorenzian-shaped I-E peaks on all surfaces in consistent with surface expansion using either an energy-dependent or a constant inner potential of 10.75 ± 0.5 eV. The widths of these same peaks on all surfaces were found to vary as $\text{E}{}^{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}$ above 40 eV and $\text{E}{}^{\mathrm{<mtext>1</mtext><mtext>3</mtext>}}$ below.     

Resonant Raman spectra of deuterated polyacetylene, (CD)x

Raman spectra of films of (CD)_x at 77K show dramatic isotope effects in intensity, as well as pronounced dispersion in band profiles as the excitation wavelength is varied throughout the visible. Long series of overtone lines as well as photoluminescence are seen in spectra of the $\text{cis}$ but not the $\text{trans}$ isomer.     

Oscillator strengths for excitons bound to impurities and quantum wells

It is argued that electron-hole correlation can have a large effect on the oscillator strengths of bound excitons, and may help to explain the observations of shallow excited states for donor bound excitons in direct gap semiconductors. For quantum wells it is found that compression of the exciton wave function yields a $\text{1}\text{L}$ dependence of oscillator strength on well width L for narrow wells.     

Planar channeling of helium ions along (100), (110) and (111) MgO

Planar channelling of 1, 1.5 and 2 MeV ⁴He⁺ ions along (100), (110) and (111) MgO have been studied experimentally using Rutherford backscattering. Values of the half angle $\text{ψ}{}^{\mathrm{P}}{}_{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}$, shoulder half angle $\text{ψ}{}^{\mathrm{s}}{}_{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}$ and surface minimum yield x^P_min have been determined for channelling with respect to the two sublattices. Agreements and discrepancies with existing theories are discussed.     

Neutron-hole strength distributions in heavy nuclei: (II). The 144, 148, 152Sm(3He, α) 143, 147, 151Sm and the 144, 148, 150, 152, 154Sm(p,d) 143, 147, 149, 151, 153Sm reactions

Valence and deep-lying neutron-hole strengths corresponding to orbits near and well below the Fermi surface have been observed in high-resolution studies of the ^{144, 148, 152}Sm(³He, α) and of the ^{144, 148, 150, 152, 154}Sm(p, d) reactions at 70 and 42 MeV bombarding energy, respectively. The explored excitation energy range was 28 MeV for the (³He, α) experiment and about 12 MeV in the (p, d) study. Complete angular distributions have been measured in both cases and the data was analyzed within the framework of the distorted waves Born approximation theory of direct reactions.For the neutron closed shell target (¹⁴⁴Sm), in addition to the well-known fragmentation of the 2d_{$\text{5}\text{2}$} and 1g_{$\text{7}\text{2}$} valence-hole strength, a new bump observed around 7.6 MeV excitation energy is excited in both reactions. This structure corresponds to the 1g_{$\text{9}\text{2}$} inner-hole strength in ¹⁴³Sm and the analysis of the (³He, α) data suggests that more than 50% of the l = 4 strength can be found between 6 and 12 MeV. When one goes to the heavier Sm isotopes, the energy spacing between valence-hole states located above and just below the N = 82 shell decreases strongly and disappears in ¹⁵¹Sm as a result of increasing deformation.Combining good energy resolution and detailed analysis of the two reactions, rather complete spectroscopic information is obtained for the valence-hole strength distributions. With regard to inner-hole states, the energy spectra exhibit a narrow structure whose centroid energy decreases from 4.4 to 2.9 MeV when the mass number increases from A = 147 to A = 153. The main peak displays an asymmetric shape with an extremely large high-energy tail. The 1h_{$\text{11}\text{2}$} hole strength is split into the Nilsson Orbitals. The narrow bumps are found to carry a large fraction of the l = 5 and l = 2 hole strengths in ^{147,149,151,152}Sm isotopes. In the high-energy tail of the structures one observes overlapping and increasing spreading of the g_{$\text{7}\text{2}$}, 2d_{$\text{5}\text{2}$} and possibly 1g_{$\text{9}\text{2}$} inner-hole strengths due to the disappearance of the N = 82 shell gap between N = 83 and N = 89 neutron numbers. The experimental hole strengths distributions are compared where possible to the predictions of the quasiparticle-phonon nuclear model or to the simple Nilsson model.     

Oscillator strengths of the first forbidden lines of rubidium

The oscillator strengths of the 5s-4d first forbidden lines of rubidium at 5165 Å were determined by performing CW tunable dye laser absorption measurements. Measured oscillator strengths of 8.06±0.48×10^-7 and 5.38±0.31×10^-7 for the ²D_{$\text{5}\text{2}$} and ²D_{$\text{3}\text{2}$} states, respectively, are compared with previously published values.     

(II) Infrared and X-ray photoelectron spectroscopy of some transition metal dithiocarbamates and xanthates

Measurements are presented for the binding energy variations of (a) (Ni, Cu) 2p_{$\text{3}\text{2}$}, S 2p and N 1s core levels in a series of Ni and Cu disubstituted dithiocarbamates and (b) (Ni, Cu) 2p_{$\text{3}\text{2}$}, and S 2p core levels in a series of Ni xanthates. These shifts, which are observed to be negative and quite large for the S 2p levels, are then correlated with the infrared absorption frequency variations for the associated intramolecular stretching vibrations of the same series. The results are interpreted in terms of a model based on atomic charges and their potential effects on both variations. The functional relationships between the binding energy and infrared frequency variations are shown to be in good agreement with the experimental results.     

Orbital classical solutions,non-perturbative phenomena and singularity at the zero coupling constant point

We try to extend previous arguments on orbital classical solutions in non-relativistic quantum mechanics to the $\text{1}\text{4}\text{λ|φ|}{}^4$ complex relativistic field theory. The single valuedness of the Green function in the semiclassical $\text{(}\text{h}\text{?}\text{→ 0)}$ limit leads to a Bohr-Sommerfeld quantization. A path integral formalism for the Green functions analogous to that in non-relativistic quantum mechanics is employed and a semiclassical approach which uses our classical solutions indicates non-perturbative effects. They reflect and $\text{e}{}^{\mathrm{<mtext>1</mtext><mtext>\lambda </mtext>}}$ singularity at the zero coupling constant point.