(searched for: doi:10.4236/sar.2016.43003)
Atoms, Volume 8; https://doi.org/10.3390/atoms8040088
In Atoms2020, 8, 23; doi:10.3390/atoms8020023, we reported on a complete optogalvanic (OG) spectrum of a discharge burning in a La–Ar gas mixture, in the spectral range 5610–6110 Å (17,851 to 16,364 cm−1). Now we are able to communicate further new energy levels, found via searching for laser-induced fluorescence lines when exciting unclassified lines from the OG spectrum. We were able to find 17 new levels, and for two further levels, the line list has extended. With the help of these 19 levels, we could classify 132 spectral lines.
Published: 29 November 2020
Journal of Quantitative Spectroscopy and Radiative Transfer, Volume 260; https://doi.org/10.1016/j.jqsrt.2020.107452
Laser spectroscopy and optogalvanic detection was applied to investigate up to now unclassified or even unknown spectral lines of atomic lanthanum (La I). The exciting laser light had wavelengths between 4300 and 6800 Å. We report the discovery of seven new energy levels. One additional level turned out to be already known, but with wrong angular momentum. Altogether 53 spectral lines could be classified as transitions of these eight levels.
Published: 18 September 2020
Journal of Quantitative Spectroscopy and Radiative Transfer, Volume 256; https://doi.org/10.1016/j.jqsrt.2020.107340
By means of laser spectroscopy and optogalvanic detection, we searched for unknown spectral lines of atomic lanthanum (La I) in the red region of the visible spectrum (6900–6200 Å). Most of the discovered lines could be interpreted as transitions between known energy levels due to wavelength and observed hyperfine structure pattern. For lines which we could not classify we searched for laser-induced fluorescence in order to identify at least one level involved in the transition. In this way we discovered 25 energy levels of La I having even parity. For two levels we could improve the accuracy of energy and hyperfine structure constants. These 27 levels classify 213 spectral lines.
Atoms, Volume 8; https://doi.org/10.3390/atoms8020023
We report on a complete optogalvanic spectrum of a discharge burning in a La-Ar gas mixture, in the spectral range 5610–6110 Å (17,851 to 16,364 cm−1). About 1900 overlapping laser scans, each between 1 and 1.5 cm−1 wide, were necessary to cover this range. The resolution of the spectra is limited by the Doppler width of the spectral features to about 0.03 cm−1 (or ca. 0.01 Å) and is comparable with a Fourier-transform spectrum, but the sensitivity is much higher. Indeed, we could find more than 1800 lines, from which about 800 could be classified as transitions between known energy levels. The main focus of the investigations was to discover previously unknown energy levels by means of excitation of unclassified spectral features.
Atoms, Volume 6; https://doi.org/10.3390/atoms6040054
The necessary tools for determining a fast and, during an experimental run, possible location of a new energy level are presented, using the findings and characterization of a new level of the La atom as an example. Due to the corresponding computer programs, the observations gained during the experiment can be immediately used.
Published: 1 November 2017
Journal of Quantitative Spectroscopy and Radiative Transfer, Volume 202, pp 193-199; https://doi.org/10.1016/j.jqsrt.2017.07.035
Atoms, Volume 5; https://doi.org/10.3390/atoms5010010
For the determination of improved energy levels of ionic spectra of elements with large values of nuclear magnetic dipole moment (and eventually large values of nuclear quadrupole moments), it is necessary to determine the center of gravity of spectral lines from resolved hyperfine structure patterns appearing in highly resolved spectra. This is demonstrated on spectral lines of Ta II, Pr II and La II. Blend situations (different transitions with accidentally nearly the same wave number difference between the combining levels) must also be considered.