Oscillator strengths of Rb quadrupole lines

The oscillator strengths of the forbidden lines of Rb (5²S_1/2-n²D_5/2 and 5²S_1/2-n²D_3/2, 4≤ n ≤9) have been measured in absorption. The dependence of the oscillator strength on the principal quantum number is qualitatively the same as calculated by Warner.⁽¹⁾ It was found that the values for the second quadrupole doublet are extremely small.     

Oscillator strengths and lifetimes of levels for ions of the rubidium isoelectronic sequence calculated by the Dirac-Fock method

The oscillator strengths f of the resonance transitions are calculated by the Dirac-Fock method for the first ten terms of the rubidium isoelectronic sequence. The variation of f values along the isoelectronic sequence is analyzed. The corresponding transition probabilities and lifetimes τ of the levels 5p ² P _1/2 and 5p ² P _3/2 are calculated. The dependence of τ on the ion charge is approximated by an analytical equation. The obtained values of f and τ are compared with experiment and other calculations.     

Oscillator strengths of ionized chromium lines in the 2413–2718 Å wavelength range

Oscillator strengths for one hundred and twenty-three Cr(II) lines, in the spectral region 2413–2718 Å, have been measured using a wall-stabilized arc. Chromium was introduced into the arc channel in a gas mixture containing Cr(ClO)₂, argon and helium. Diagnostic studies were carried out by a numerical solution of a set of equations which describes plasma properties for the case of partial LTE. The absolute scale was established by using the line 2672.83 Å of Cr(II) with accurately known ?-value. The measured oscillator strengths are compared with theoretical calculations. Discrepancies have been found to be greater than the experimental uncertainties.     

Self-broadening of principal series lines of rubidium at high number densities and oscillator strengths

The self-broadening of principal series lines of rubidium and the corresponding oscillator strengths have been measured using a steel absorption tube heated up in an electric furnace. The line profiles were obtained from absorption measurements using a grating spectrograph of high resolution in the temperature range of 340–490 °C; the number densities varied from 5 · 10¹⁶ to 8 · 10¹⁷cm^?3. The half widths deduced from the absorption profiles disagree with the classical impact approximation based on dipole-dipole interaction but approach closely the asymptotic values of the quantum-mechanical Reinsberg theory and of the “short-range”-calculations of Presnyakov. Oscillator strengths for the higher series lines were evaluated from the spectra agreeing very well with the asymptoticn ^*?3-hydrogen-like slope of the values.     

On the observability of forbidden lines

The disappearance of forbidden lines for O III at intermidiate plasma densities may be due to background wing emission of the stronger allowed lines, rather than to Stark broadening of the forbidden lines as suggested recently. The general conclusion is supported that the classical explanation of quenching is erroneous, at least for O III.     

On the detectability of forbidden lines

We show that the traditional interpretation of the non-detection of forbidden lines in dense natural plasmas is based on a misunderstanding. The central intensity of the line, taken to be a measure of detectability, is shown to have a maximum as a function of electron density and to be a linear function of electron density in tenuous plasmas.     

Oscillator strengths in the boron isoelectronic sequence

The quantum defect orbital formalism in both its relativistic and non-relativistic versions has been applied to the calculation of oscillator strengths in the sharp spectral series of some boron-like systems. The results are presented in both tabular and graphical forms.     

Oscillator strengths of ultraviolet V(II) lines from measurements in a vanadium-helium plasma

A V-He plasma has been produced in a well-stabilized arc. Oscillator strengths for 66 V(II) lines in the range 2342–2617 Å have been determined. Comparisons with theoretical values show large discrepancies for about 25% of the lines, possibly due to errors in calculations and in term classifications.     

Xenon: Oscillator strengths and photoionization

Electron energy loss spectra of Xe have been analyzed by means of Fano and Lu's collision theory of spectra. A new and improved set of empirical parameters has been determined,eigenquantum defects, orthogonal transformation matrix, anddipole matrix elements. These data have been used to calculate the autoionized profile and the asymmetry parameterβ of the angular distribution of photoelectrons. The autoionization profile is in agreement with the measurements of Huffman, Tanaka, and Larrabee. In addition, the theory predicts a distinct interference effect betweens andd excitation. The energetic shifting between the measured and calculated asymmetry parameterβ observed previously is removed. Nevertheless, deviations concerning the magnitude ofβ nears state excitation are still left unexplained. They are probably due to insufficient resolution of the photoelectron measurement.     

Oscillator strengths for singly ionized oxygen

The electric dipole oscillator strengths for multiplet and individual lines between some doublet and quartet levels have been calculated using the weakest bound electron potential model theory (WBEPMT) in singly ionized oxygen. We employed both numerical Coulomb approximation (NCA) wave functions and numerical non-relativistic Hartree-Fock (NRHF) wave functions for expectation values of radii in determination of parameters. The calculated oscillator strengths have been compared with available theoretical and experimental results. A good agreement with results in literature has been obtained. Moreover, oscillator strengths not existing in the literature for some highly excited levels have been obtained using this method. Electronic supplementary material  Supplementary Online Material     

Xenon: Oscillator strengths and photoionization

Electron energy loss spectra of Xe have been analyzed by means of Fano and Lu's collision theory of spectra. A new and improved set of empirical parameters has been determined,eigenquantum defects, orthogonal transformation matrix, anddipole matrix elements. These data have been used to calculate the autoionized profile and the asymmetry parameter of the angular distribution of photoelectrons. The autoionization profile is in agreement with the measurements of Huffman, Tanaka, and Larrabee. In addition, the theory predicts a distinct interference effect betweens andd excitation. The energetic shifting between the measured and calculated asymmetry parameter observed previously is removed. Nevertheless, deviations concerning the magnitude of nears state excitation are still left unexplained. They are probably due to insufficient resolution of the photoelectron measurement.     

Oscillator strengths and lifetimes for the P XII

Semi-empirical weighted oscillator strengths (gf) and lifetimes presented in this work for all experimentally known electric dipole P XII spectral lines and energy levels were computed within a multiconfiguration Hartree-Fock relativistic approach. In this calculation, the electrostatic parameters were optimized by a leastsquares procedure in order to improve the adjustment to experimental energy levels. The method produces lifetime and gf values that are in agreement with intensity observations used for the interpretation of spectrograms of solar and laboratory plasmas.     

Oscillator strengths of Cs and Rb-like ions

Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 56, No. 1, pp. 13–17, January, 1992.     

Oscillator strengths and transition energies of diamond

The spectrum of the dielectric constant of three different samples of diamond in the 5–30-eV region is decomposed in thirteen elementary components. The main parameters of components are determined, and their nature is found on the basis of the band model.     

Oscillator strengths in the Cameron system of carbon monoxide

Relative oscillator strengths in the Cameron system of CO(a³Π ← X¹Σ) have been observed in absorption for six bands (υ′ = 0–5, υ″ = 0) with the result, normalized to the absolute (0, 0) band measurement of Hasson and Nicholls, $\text{?}{}_{00}\text{= (1.62±0.07) × 10}{}^{\mathrm{?7}}$, $\text{?}{}_{10}\text{= (1.96±0.09) × 10}{}^{\mathrm{?7}}$, $\text{?}{}_{20}\text{= (1.41±0.04) × 10}{}^{\mathrm{?7}}$, $\text{?}{}_{\mathrm{3\; 0}}\text{= (0.72±0.03) × 10}{}^{\mathrm{?7}}$, $\text{?}{}_{40}\text{= (0.31±0.02) × 10}{}^{\mathrm{?7}}$, $\text{?}{}_{50}\text{= (0.14±0.01) × 10}{}^{\mathrm{?7}}$. The density of CO was modulated with a motor-driven vacuum valve and synchronous fluctuations (?1 per cent) in the transmitted intensity detected with a lock-in amplifier. Peak pressure in the 21 cm absorption cell was approximately 10 torr. A curve of growth analysis was used to correct saturation effects by less than 3 per cent.     

Oscillator strengths and lifetimes for the S V spectrum

The semi-empirical weighted oscillator strengths (gf) and the lifetimes presented in this work for all experimentally known electric dipole S V spectral lines and energy levels were carried out in a multiconfiguration Hartree–Fock relativistic (HFR) approach. In this calculation, the electrostatic parameters were optimized by a least-squares procedure, in order to improve the adjustment to experimental energy levels. This method produces lifetime values and gf values that are in agreement with intensity observations used for the interpretation of spectrograms of solar and laboratory plasmas.     

Oscillator strengths of neutral and singly ionised molybdenum

Oscillator strengths of 174 Mo(I) and 58 Mo(II) lines in the range 2470–5570 Å were obtained from wall-stabilised arc and hollow cathode measurements. Sets of relative f-values were determined by a combination of hook and emission measurements requiring no assumptions concerning the plasma state. The sets have been enlarged considerably by evaluating spectra recorded with a Fourier spectrometer. The relative Mo(I) f-values were converted to an absolute scale by means of radiative lifetimes measured by P. Zimmermann and his group. The overall uncertainties are within 10–35%. Since lifetimes of Mo(II) levels are not yet available, only relative Mo(II) f-values are presented.