Measurements of the oscillator strengths for the 6p7s (1/2,1/2)1→6pnp (1/2,3/2)2 Rydberg transitions of lead (original) (raw)
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Three-step excitation of the ?, nd, ng autoionizing Rydberg levels via the 6p6f ? level of lead
Journal of Physics B-atomic Molecular and Optical Physics, 1997
New spectra of lead consisting of the autoionizing Rydberg energy region excited via the 0953-4075/30/19/010/img12 level is presented. Fifty levels along with their FWHM widths are reported. Eleven levels of the 0953-4075/30/19/010/img13 configuration have been reported for the first time. Besides two unassigned levels with effective quantum number 8.446 and 10.86, five new levels of the 0953-4075/30/19/010/img14 configuration have been observed. An unexplained phenomenon is observed where the 0953-4075/30/19/010/img15 levels for n > 14 do not show up via the 0953-4075/30/19/010/img12 route in contrast to the fact they are observed as strong resonances when excited via other similar routes, namely, 0953-4075/30/19/010/img17 and 0953-4075/30/19/010/img18 levels.
Three-step laser excitation of the ?, ? J = 1, 2, 3 autoionizing Rydberg levels of lead
Journal of Physics B-atomic Molecular and Optical Physics, 1997
We report here first measurements of the odd-parity 0953-4075/30/5/013/img12 J =1, 2 and 0953-4075/30/5/013/img13 J = 0, 1, 2, 3 autoionizing Rydberg levels of lead using a three-step laser excitation scheme in conjunction with an atomic beam apparatus. Four initial levels 0953-4075/30/5/013/img14 J = 1, 2 were chosen for the excitation of the final levels. The assignments have been made using the 0953-4075/30/5/013/img15-coupling scheme for the observed levels. The Rydberg series 0953-4075/30/5/013/img16, 0953-4075/30/5/013/img17, 0953-4075/30/5/013/img18 and 0953-4075/30/5/013/img19 as well as 0953-4075/30/5/013/img20 are reported. All the observed series exhibit constant quantum defects with respect to the ionization potential value 0953-4075/30/5/013/img21. The full widths at half the maximum 0953-4075/30/5/013/img22 of the observed levels are also reported.
Oscillator strength measurements of the 5s6s S10→5snp P11 Rydberg transitions of strontium
Physical Review A, 2009
We report the experimentally determined oscillator strengths for the 5s6s 1 S 0 → 5snp 1 P 1 Rydberg transitions of strontium using two-step excitation in conjunction with a thermionic diode ion detector. The absolute photoionization cross section from the 5s6s 1 S 0 excited state has been determined by adjusting the polarization vector of the ionizing laser beam parallel, perpendicular, and at the magic angle with respect to that of the exciting dye laser. The measured absolute value of the photoionization cross section 0.9Ϯ 0.2 Mb at the 5s threshold is used to extract the f values of the 5s6s 1 S 0 → 5snp 1 P 1 ͑26Յ n Յ 73͒ Rydberg transitions. The oscillator strength in the discrete region merges smoothly to the oscillator strength density at the ionization threshold.
Three step excitation of the ? autoionizing Rydberg levels via ? levels of lead
Journal of Physics B-atomic Molecular and Optical Physics, 1997
In this paper we present the Rydberg autoionization spectra of lead from 73 000 cm −1 to the 6p 3/2 ionization limit at 73 900.65 cm −1 excited from the 6p7f and 6p8f 1 2 [ 5 2 ] 2 intermediate levels. Term energies and FWHM of 40 lower n levels (n = 10-15) of the 6p 3/2 nd, (n + 2)s J = 1-3 Rydberg series are reported for the first time.
Oscillator strength measurements of the 4s5s 3S1 → 4snp 3Po2 Rydberg transitions of zinc
Spectroscopy Letters, 2019
In the present experimental work, oscillator strengths of the 4s5s 3 S 1 ! 4snp 3 P o 2 (18 n 53) Rydberg transitions of zinc are reported. The stepwise laser excitation from the ground state 4s 2 1 S 0 was achieved using three dye laser beams simultaneously pumped by the second (532 nm) and third (355 nm) harmonics of a Q-switched Nd: YAG (Neodymium-doped yttrium aluminum garnet) laser. The vapor containment and detection system was a single wire thermionic diode ion detector operating in space charge limited mode. A trend of the above-mentioned f-values from n ¼ 18 to 53 versus the principle quantum number n has been presented. Furthermore, continuity has been verified between the discrete f-values and the oscillator strength density at the threshold.
The Astrophysical Journal, 2006
One of the processes controlling the interstellar CO abundance and the ratio of its isotopologues is photodissociation. Accurate oscillator strengths and predissociation rates for Rydberg transitions are needed for modeling this process. We present results on absorption from the E 1 Π − X 1 Σ + (1-0) and B 1 Σ + − X 1 Σ + (6-0) bands at 1051 and 1002Å, respectively, and the vibrational progression W 1 Π − X 1 Σ + (v ′ -0) bands with v ′ = 0 to 3 at 972, 956, 941, and 925Å, respectively. The corresponding spectra were acquired at the high resolution (R ≈ 30,000) SU5 beam line at the Super ACO Synchrotron in Orsay, France. Spectra were obtained for the 12 C 16 O, 13 C 16 O, and 13 C 18 O isotopologues. These represent the most complete set of measurements available. Comparison is made with earlier results, both empirical and theoretical. While earlier determinations of oscillator strengths based on absorption from synchrotron radiation tend to be somewhat smaller than ours, the suite of measurements from a variety of techniques agree for the most part considering the mutual uncertainties. For the bands studied here, their relative weakness, or their significant line widths arising from predissociation, minimizes potential problems from large optical depths at line center in absorption measurements. Predissociating line widths could generally be extracted from the spectra thanks to the profile simulations used in the analysis. In many cases, these simulations allowed us to consider e and f parity levels separately and to determine the dependence of the width on rotational quantum number, J. Our results are consistent with earlier determinations, especially the widths inferred from laser experiments.
We have carried out measurements of absolute photoionization cross sections of the 4p excited levels and oscillator strengths of the 4p-nd Rydberg transitions in potassium using a two-step photo-ex-citation and ionization technique in conjunction with a thermionic diode ion detector. The measurements were conducted using the linearly polarized laser light and the absolute values of the cross sections from the 4p 2 P 3/2 and 2 P 1/2 excited levels have been determined at the ionization threshold as (6.37 0.9) Mb and (5.47 0.8) Mb respectively. In addition, photoionization cross sections have been determined at various ionizing wavelengths above the first ionization threshold to explore different energy regions of the continuum. The oscillator strengths for the 4p 2 P 1/2-nd 2 D 3/2 and 4p 2 P 3/2-nd 2 D 3/2,5/2 Rydberg transitions have been deduced by using the measured cross sections of the 4p 2 P 1/2 and 2 P 3/2 levels at the ionization threshold. The new results are in good agreement with the available theoretical and experimental data.
The European Physical Journal D, 2007
We present experimentally measured absolute values of the photoionization cross sections from the 5s5p 1 P1 and 5s5p 3 P1 excited states of strontium at the first ionization threshold as 11.4 ± 1.8 Mb and 10.7 ± 1.7 Mb respectively using saturated absorption technique along with a thermionic diode ion detector in conjunction with a Nd:YAG pumped dye laser system. These threshold photoionization cross sections values have been utilized to determine the oscillator strengths of the 5s5p 1 P1 → 5snd 1 D2 and 5s5p 3 P1 → 5snd 3 D2 Rydberg transitions. The oscillator strength densities in the continuum corresponding to the 5s5p 3 P1 excited state have also been determined by measuring the photoionization cross sections at five ionizing wavelengths above the first ionization threshold. Smooth merging of the discrete f -values into the oscillator strength densities has been observed for the 5s5p 3 P1 → 5snd 3 D2 series across the ionization threshold.
The Journal of Chemical Physics, 2010
Relative partial photoionization cross sections and angular distribution parameters  have been measured for the first and fourth ͑5p͒ −1 photoelectron ͑PE͒ bands of atomic iodine by performing angle-resolved constant-ionic-state ͑CIS͒ measurements on these PE bands between the 1 D 2 and 1 S 0 ͑5p͒ −1 ionic thresholds in the photon energy region of 12.9-14.1 eV. Rydberg series arising from the 5p → ns and 5p → nd excitations are observed in both the first PE band, I + ͑ 3 P 2 ͒ ← I͑ 2 P 3/2 ͒, and the fourth PE band, I + ͑ 1 D 2 ͒ ← I͑ 2 P 3/2 ͒, CIS spectra. For each Rydberg state, the resonance energy, quantum defect, linewidth, line shape, and photoelectron angular distribution parameter  have been determined. For the -plots for each PE band, only resonances corresponding to 5p → nd excitations are observed; no resonances were seen at photon energies corresponding to the 5p → ns resonances in the CIS spectra. The -plots are interpreted in terms of the parity unfavored channel with j t =4 being the major contributor at the 5p → nd resonance positions, where j t is the quantum number for angular momentum transferred between the molecule, and the ion and photoelectron. Comparison of the results obtained with those published for bromine shows reasonably good agreement for the CIS spectra but poor agreement for the -plots. It appears that parity unfavored channels are playing a greater role in the valence ͑np͒ −1 ionization of atomic iodine than in the corresponding ionization of atomic bromine.