Odd-parity Levels Research Articles

New energy levels of atomic holmium discovered by laser spectroscopy in the near infrared spectral range

A combination of optogalvanic spectroscopy and laser-induced fluorescence spectroscopy with a continuous wave tunable single mode Ti-Sa laser was applied to find new energy levels of atomic holmium. Free and excited holmium atoms were produced in a liquid nitrogen-cooled hollow-cathode lamp. In this study, we examined 35 spectral lines of Ho I in the near-infrared wavelength range from 698 nm to 833 nm. Altogether, 16 new energy levels have been discovered, 5 levels of even parity and 11 levels of odd parity. Another four energy levels have been discovered but have already been published by another research group. Data on the hyperfine structure for the new levels are presented. Additionally, hyperfine structure data of three known levels of even parity were determined for the first time. The existence of the new energy levels was confirmed by analyzing 60 lines of previously measured Fourier transform spectra to precisely determine the energy of the levels.

Hyperfine structure and even-parity new levels evaluation in the holmium atom

In this work investigations of the hyperfine structure for more than 100 spectral lines of the holmium atom are presented, performed with laser excitation in a hollow cathode and detection of laser induced fluorescence. Energy values and the hyperfine structure constants A and B for 11 new electronic levels were determined. Hyperfine structure constants were evaluated for 26 even-parity levels with known energies, and for another 20 levels the constants were confirmed. For 3 levels the values of J quantum numbers were corrected. Additionally, corrected A and B values for 18 odd-parity levels were determined.

Fine- and hyperfine structure semi-empirical studies of singly ionised cobalt. Odd-parity configurations system

We present the results of semi–empirical calculations of the fine structure (fs) and the hyperfine structure (hfs) for the odd–parity level system of the cobalt ion (Co II), using all available experimental data. The performed calculations showed a very good agreement, within experimental uncertainty, between the total of 146 experimental hfs A values and the calculated values. An attempt was made to resolve significant discrepancies in some experimental results that were recently published by two research teams. The predicted energies of electronic levels, together with their Landé gJ factors as well as magnetic dipole Ahfs constants for unknown levels are also provided.

Hyperfine structure investigations of the odd-parity electronic levels of the terbium atom

In the present work the hyperfine structure constants A and B were determined for 26 odd-parity energy levels of the terbium atom. Altogether 62 spectral lines in the spectral range between 483 - 538 nm were examined, using the method of laser induced fluorescence in a hollow cathode discharge lamp. All the results are presented for the first time. Additionally, the constants for 4 even-parity energy levels, previously reported by our research group, were reevaluated and slightly corrected.

Resonance ionization spectrum of autoionization states of lutetium atom

<sup>177</sup>Lu is an important medical isotope used in imaging-guided radiotherapy, and it can be produced by irradiating <sup>176</sup>Lu or <sup>176</sup>Yb with high abundance. With an increasing demand for medical isotopes, it is very essential to improve the supply capacity for <sup>177</sup>Lu. The multi-step multi-color photoionization method is an effective method to obtain isotopes, and the information of odd-parity autoionization levels is essential. Laser resonance ionization spectroscopy is one of a few spectroscopic experimental methods that can study autoionization levels. An experimental system is developed for the frontier spectroscopic research, and it consists of custom-made tunable lasers and a high-resolution time of flight mass spectrometer. The lifetime of the excited state 35274.5 cm<sup>–1</sup> is measured to be (31.6 ± 1.7) ns by the delayed photoionization method for the first time. A three-step three-color photoionization process is used to detect the autoionization levels, with a delay of 30 ns between <i>λ</i><sub>2</sub> – <i>λ</i><sub>1</sub> and <i>λ</i><sub>3</sub> – <i>λ</i><sub>2</sub> respectively, in order to avoid any unexpected transitions. Forty-seven odd-parity autoionization levels are obtained, of which 33 levels are discovered for the first time, and the <i>λ</i><sub>2</sub> and <i>λ</i><sub>1</sub> are blocked to exclude possible interference peaks, such as the <i>λ</i><sub>1</sub>+<i>λ</i><sub>3</sub>+<i>λ</i><sub>3</sub> transition. Several autoionization levels show asymmetrical peak shapes, and the Fano fitting is carried out for all the levels to determine the widths and relative transition strengths of the autoionizing transitions. This study provides critical data for the high-efficient photoionization of lutetium atoms in the visible range. The angular momenta of 21 odd-parity autoionization levels in an energy range of 50650–51650 cm<sup>–1</sup> are identified for the first time, which provides a reference for determining the forbidden state of electric dipole transitions from other excited states and ascertaining the electronic configuration.

Determination of the energies of new electronic levels of the holmium atom and investigation of their hyperfine structure

In the present work 27 electronic energy levels of the holmium atom, with previously unknown energies, were identified for the first time. Experimental data were acquired with the method of laser spectroscopy in a hollow cathode discharge lamp, with laser induced fluorescence detection. Recorded patterns for 79 spectral lines of holmium in the spectral range 485–535 nm enabled determination of the hyperfine structure constants A and B for 23 odd-parity levels and 11 even-parity levels. For 31 levels the results are presented for the first time. The energy values for the previously unknown levels were determined, too.

Semi-empirical studies on odd parity levels system of manganese atom in multiconfiguration approximation

We present the results of semi-empirical calculations of the fine structure (fs) and the hyperfine structure (hfs) for the odd-parity level system of the manganese atom in a large multiconfiguration basis. Recently, new measurements applying laser induced fluorescence on an atomic beam and in a hollow cathode discharge lamp provided the hyperfine structure constants A and B for altogether 50 odd-parity levels. Therefore, a hyperfine structure many-body parameterization method was successfully used for such complicated system, composed of 71 configurations. In general, a good agreement between the experimental and the calculated values for the fs and hfs fits was obtained.

Landé [formula omitted] factors of the odd-parity electronic levels of the terbium atom determined by laser spectroscopy

In the present work the experimentally determined values of Landé gJ factors for 20 odd-parity electronic levels of atomic terbium are presented. The Zeeman splitting of the hyperfine structure was investigated using the method of laser induced fluorescence in a hollow cathode discharge lamp in a constant magnetic field. All of the values were determined for the first time, by the analysis of 32 spectral lines, recorded in the spectral range between 492 and 609 nm. Moreover, the gJ factors for 15 even-parity energy levels, reported in the available literature, were verified.

Experimental and Theoretical Radiative Parameters of Highly Excited Odd-parity Levels in Ir ii

Using the time-resolved laser-induced fluorescence technique, the radiative lifetimes for 15 odd-parity levels from 47,003 to 61,475 cm−1 in Ir ii were measured. To the best of our knowledge, 11 lifetime results among these levels are reported for the first time, and hence they should be a good complement to the measured lifetime data of 10 levels previously published in the literature. The pseudorelativistic Hartree–Fock including core-polarization corrections method was used to calculate the lifetimes and branching fractions (BFs) of the investigated energy levels. Combining the experimental lifetime with the theoretical BFs, the transition probabilities and oscillator strengths for 124 transitions were determined.

Landé [formula omitted] factors of the even-parity electronic levels of the terbium atom

In the present work Landé gJ factors for 17 even-parity electronic levels of the terbium atom are presented. The spectra of the Zeeman splitting of the hyperfine structure were recorded with the method of laser spectroscopy in a hollow cathode discharge lamp in a constant magnetic field, with laser induced fluorescence detection. The analysis of 47 spectral lines of terbium in the spectral range between 490 and 609 nm enabled the determination of the gJ factors for the presented even-parity levels for the first time. Moreover, verification of the gJ factor values for 17 odd-parity levels, previously reported by other authors from the analysis of Fourier transform spectra.

Measurements and Calculations of Radiative Parameters for Odd-parity Levels in Nb ii

Abstract Experimental radiative lifetimes for 34 odd-parity levels belonging to 4d 35p and 4d 25s5s configurations of Nb ii were measured by the time-resolved laser-induced fluorescence method. The results range from 2.2 to 11.5 ns, and 30 of them were reported for the first time, as far as we know. The theoretical radiative lifetimes for these levels were also calculated by the pseudorelativistic Hartree–Fock method including core-polarization contributions (HFR+CPOL) and the fully relativistic multiconfiguration Dirac–Hartree–Fock method, and branching fractions for these levels were also calculated by HFR+CPOL. By combining the experimental lifetimes and the calculated branching fraction values, the semiempirical transition probabilities and oscillator strengths for 389 Nb ii lines were obtained.

Experimental and Theoretical Radiative Parameters of Highly Excited Levels in Re ii

Abstract Natural radiative lifetimes of 22 odd-parity levels of Re ii in the energy range between 43,937.7 and 65,572.3 cm−1 were measured by the time-resolved laser-induced fluorescence method. To our knowledge, the lifetimes for 18 out of 22 levels were measured for the first time. The theoretical radiative lifetimes and branching fractions (BFs) for these levels were obtained from pseudorelativistic Hartree–Fock calculations including core-polarization effects. By combining the experimental lifetimes and calculated BFs, a set of semiempirical transition probabilities and oscillator strengths for 232 Re ii lines were determined. The radiative parameters obtained in the present work will greatly enrich the atomic database of Re ii and hence are expected to be helpful for astrophysicists in Re abundance evaluation of stars.

Revised Energy Levels of Atomic Lanthanum Considering Hyperfine Structure

Abstract The experimental wavenumbers of 2118 spectral lines from calibrated Fourier transform (FT) spectra have been used to determine revised energy values of 405 fine structure levels of atomic lanthanum, 264 levels of even and 141 levels of odd parity, respectively. For the determination of the level energies a weighted global fit of the center-of-gravity (cg) wavenumbers of all 2118 spectral lines has been done. All lines have been classified previously by different spectroscopic methods and by different authors. In order to achieve high accuracy, the hyperfine (hf) structure was taken into account when determining the cg wavenumbers from the FT spectra. The total uncertainty for all revised energy levels lies below 0.007 cm−1. A compilation of all revised energy levels along with their hf structure data is given, as well as a list of the spectral lines used in this investigation.

Semi-empirical predictions of energy levels, their Landé [formula omitted] factors and hyperfine structure for the odd-parity configuration system of Ho II

We present the results of semi–empirical calculations of the fine (fs) and the hyperfine structure (hfs) for the odd–parity level system of the holmium ion (Ho II), using all available data. A parametric analysis, both for a fs and hfs, for 5 configurations with all the 4f10 and 4f11 core states, by taking into account the second–order effects of perturbation theory, was performed for the first time.The predicted energies of electronic levels together with their Landé gJ factors as well as magnetic dipole A and electric quadrupole Bhfs constants for unknown levels are listed.The importance of the Landé gJ factors in atomic and quantum physics, as well as a complete lack of experimental data on this subject, make our calculated values all the more useful.

Landé [formula omitted] factors of odd-parity electronic levels of the holmium atom

In the present work results of Landé gJ factors measurements for 18 electronic levels of the holmium atom are presented. Recorded Zeeman spectra of the hyperfine structure, observed with the method of laser spectroscopy in a hollow cathode discharge lamp, placed in constant magnetic field, with laser induced fluorescence detection, were analyzed. Results obtained for 33 spectral lines of holmium in the spectral range of 488-677nm enabled the determination of the corresponding gJ factors. For 12 odd-parity levels of Ho I and one even-parity level these factors are determined for the first time.

New odd-parity energy levels of the neutral lanthanum atom

The discovery of 22 new energy levels of the La atom, having odd parity, is reported. These levels were derived from an analysis of unclassified spectral lines found either in optogalvanic spectra and/or Fourier transform spectra. The reliability of results obtained from the combination principle of Ritz was verified by hyperfine structure investigations. Further three new odd-parity levels of the first La ion are found. For two already known odd-parity levels substantial changes, concerning total angular momentum and hyperfine structure constants A, must be made.

Investigations of odd-parity autoionization levels of atomic samarium using three-color resonance ionization spectroscopy

Three-color three-step laser resonance ionization spectroscopy has been employed to investigate the autoionization spectra of atomic samarium in the energy region 50,330 - 51,160 cm−1. The measurements were carried out in an atomic beam coupled to a linear time of flight mass spectrometer. Fifty-five odd-parity autoionization levels of atomic samarium in the above-mentioned energy region have been observed using three excitation schemes. Among these, fifty autoionization levels are new. The total angular momenta of eighteen odd-parity autoionization levels have been assigned uniquely.

Odd-parity autoionizing levels of uranium observed by two-color two-step photoionization optogalvanic spectroscopy

Two-color two-step photoionization optogalvanic spectroscopy was performed using high-repetition-rate titanium sapphire lasers and a uranium hollow cathode lamp to find the two-step resonance ionization schemes of uranium. Many ionization transitions were observed by exciting uranium atoms in a ground state into five, even parity, excited levels with the first-step laser and by scanning the second-step laser wavelengths. By blocking the first-step laser, single-color, two-photon ionization transitions were also identified. From these results, we have found more than 50 odd-parity autoionizing levels of uranium in the energy, ranging from the ionization potential (49958.4 cm−1) to 51 150 cm−1. The determined energy levels are within ∼±1 cm−1 of previously reported values.

New odd-parity fine structure levels of Pr I with J = 1/2, 3/2 and 5/2

In continuation of our previous publication on experimental laser spectroscopic investigations of the spectrum of the praseodymium atom in the visible region, the present paper reports the discovery of 65 new odd-parity fine structure levels of Pr I. Pr I atoms sputtered in a low-pressure hollow cathode discharge lamp were excited using tunable laser light. The excitation wavelengths were selected using a Fourier transform spectrum. In these investigation, 411 spectral lines were classified as belonging to the newly discovered fine structure levels. From the observed hyperfine structure patterns, the hyperfine constants of the combining levels could be determined. For the majority of the newly discovered levels their existence and the obtained hf constants were verified by investigation of two or several transitions from different lower known energy levels. Levels introduced due to only one excitation are discussed in more details.

Optogalvanic spectroscopy of the Zeeman structure of argon energy levels close to the ionization limit

The Lande gJ factors for high lying states of the argon atom by laser optogalvanic spectroscopy were measured, in most cases with an uncertainty of less than 0.005. The Zeeman structure of 12 argon lines with wavelengths in the range 598.7-612.8 nm was investigated. We determined Lande gJ factors for 9 odd parity levels and verified the data for several other levels.