- ID:
- ivo://CDS.VizieR/J/ApJS/228/16
- Title:
- Spectra of a Holmium in the near-UV. I. Ho I.
- Short Name:
- J/ApJS/228/16
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Fourier Transform spectra of a Holmium hollow cathode discharge lamp have been investigated in the UV spectral range from 25000 up to 31530cm^-1^ (317 to 400nm). Two Ho spectra have been measured with neon and argon as buffer gases. Based on the intensity ratios from these two spectra, a distinction was made between atomic and ionic lines (ionic lines are discussed in an accompanying paper). Using the known Ho I energy levels, 71 lines could be classified as transitions of atomic Ho, 34 of which have not been published previously. Another 32 lines, which could not be classified, are listed in the literature and assigned as atomic Ho. An additional 370 spectral lines have been assigned to atomic Ho based on the signal-to-noise ratio in the two spectra measured under different discharge conditions, namely with buffer gases argon and neon, respectively. These 370 lines have not been previously listed in the literature.
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- ID:
- ivo://CDS.VizieR/J/ApJS/228/17
- Title:
- Spectra of a Holmium in the near-UV. II.
- Short Name:
- J/ApJS/228/17
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Fourier Transform spectra of Holmium (Ho) in the UV spectral range from 31530 to 25000cm^-1^ (317 to 400nm) have been investigated, particularly focusing on the ionic lines. The distinction between the different degrees of ionization (I, II, and III) is based on differences in signal-to-noise ratios from two Ho spectra, which have been measured with different buffer gases, i.e., neon and argon. Based on 106 known Ho II and 126 known Ho III energy levels, 97 lines could be classified as transitions of singly ionized Ho and 9 lines could be classified as transitions of doubly ionized Ho. Of the 97 Ho II lines, 6 have not been listed in the extant literature. Another 215 lines have been assigned to Ho II, though they could not be classified on the basis of the known energy levels.
- ID:
- ivo://CDS.VizieR/J/ApJS/239/3
- Title:
- Spectroscopic accuracy for B-like ions with Z=24-30
- Short Name:
- J/ApJS/239/3
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report calculations of spectroscopic accuracy for 513 states in the B-like ions with Z=24-30. The energy levels and transition rates are calculated using the second-order many-body perturbation theory, while multiconfiguration Dirac-Hartree-Fock calculations are performed to support the former results. The present two sets of results agree excellently with each other, and can be used as benchmarks in the future. The electron-impact excitation (EIE) collision strengths are calculated based on independent processes and isolated resonances approximation using the distorted wave method. Based on the present atomic data, the spectral lines of these ions are simulated using a collisional radiative model. The amount of energy, transition data, and EIE collision strengths of high accuracy are significantly increased for several B-like ions of astrophysical interest, where experimental data are still very scarce. The results can be used in line identification, plasma modeling, and diagnostics of astrophysical plasmas.
- ID:
- ivo://CDS.VizieR/J/A+A/538/A52
- Title:
- Spectroscopic data for ionized scandium
- Short Name:
- J/A+A/538/A52
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Spectroscopic data for scandium is sparse, while an extensive set is needed to introduce this element into stellar opacity calculations and, more importantly, into stellar models dealing with radiative diffusion. Our goal is to provide extensive energy levels and radiative transitions data for nineteen ionization stages of scandium relevant to stellar interiors, namely from Sc III to Sc XXI. We used the FAC code. This code provides ab initio theoretical values for energy levels in jj-coupling and oscillator strengths of all permitted transitions. Detailed correspondences are established with compiled data from the National Institute of Standards and Technology (NIST) database, to locate as much as possible the observed levels and lines at their experimental values and to estimate the quality of our data. Comparisons were also made with the spectroscopic data delivered by Kurucz. The theoretical data retained in tables include 21842 levels and more than two millions transitions. By comparison, the NIST compilation gives a total of 820 levels and 677 gf-values. The good agreement obtained when comparing the new data with those of the NIST compilation demonstrates their quality. This work on scandium shows that the FAC code is efficient in providing spectroscopic data that are unavailable from laboratory analyses but necessary for accurate simulations of stellar plasmas.
- ID:
- ivo://CDS.VizieR/J/A+A/548/A71
- Title:
- Spectroscopy and ISM detection of formamide
- Short Name:
- J/A+A/548/A71
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Formamide is the simplest bearer of peptide bond detected in the interstellar medium (ISM). There still exists a lack of laboratory data on its rotational spectrum in THz domain. We measured the rotational spectrum of formamide in the frequency range 400-950GHz. The ground and the first excited vibrational state of the normal species as well as the ground state of ^13^C isotopic species were analysed. The results obtained represent an extension by a factor of two in frequency range com- pared to previous studies. Among all transitions frequencies in the dataset about 45% are new measurements. A reliable set of rotational constants allows accurate predictions of transition frequencies in THz domain. Based on the spectroscopic results the v12=1 excited vibrational state of formamide was detected in the IRAM 30m line survey of Orion KL for the first time in the ISM.
- ID:
- ivo://CDS.VizieR/J/A+A/642/A29
- Title:
- Spectroscopy of CH2(CN)2 and CNCH2CN
- Short Name:
- J/A+A/642/A29
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Thioformamide NH_2_CHS is a sulfur-bearing analog of formamide NH_2_CHO. The latter was detected in the interstellar medium back in the 1970s. Most of the sulfur-containing molecules detected in the interstellar medium are analogs of corresponding oxygen-containing compounds. Therefore, thioformamide is an interesting candidate for a search in the interstellar medium. A previous study of the rotational spectrum of thioformamide was limited to frequencies below 70GHz and to transitions with J<=3. The aim of this study is to provide accurate spectroscopic parameters and rotational transition frequencies for thioformamide to enable astronomical searches for this molecule using radio telescope arrays at millimeter wavelengths. The rotational spectrum of thioformamide was measured and analyzed in the frequency range 150 to 660GHz using the Lille spectrometer. We searched for thioformamide toward the high-mass star-forming region Sagittarius (Sgr) B2(N) using the ReMoCA spectral line survey carried out with the Atacama Large Millimeter/submillimeter Array (ALMA). Accurate rigid rotor and centrifugal distortion constants were obtained from the analysis of the ground state of parent, ^34^S, ^13^C, and ^15^N singly substituted isotopic species of thioformamide. In addition, for the parent isotopolog, the lowest two excited vibrational states, v_12_=1 and v_9_=1, were analyzed using a model that takes Coriolis coupling into account. Thioformamide was not detected toward the hot cores Sgr B2(N1S) and Sgr B2(N2). The sensitive upper limits indicate that thioformamide is nearly three orders of magnitude at least less abundant than formamide. This is markedly different from methanethiol, which is only about two orders of magnitude less abundant than methanol in both sources. The different behavior shown by methanethiol versus thioformamide may be caused by the preferential formation of the latter (on grains) at late times and low temperatures, when CS abundances are depressed. This reduces the thioformamide-to- formamide ratio, because the HCS radical is not as readily available under these conditions.
- ID:
- ivo://CDS.VizieR/J/A+A/623/A162
- Title:
- Spectroscopy of CH2(CN)2 and CNCH2CN
- Short Name:
- J/A+A/623/A162
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Nitriles constitute almost 20% of the molecules observed in the interstellar medium, whereas only one dinitrile and one isocyanonitrile compound have been detected up to now. The lack of detections of such compounds may be partially explained by the lack of accurate spectroscopic data on their rotational spectra. Two small seven-atom dinitriles, malononitrile NCCH_2_CN and isocyanoacetonitrile NCCH_2_NC, were chosen as target species for this study. For malononitrile the goal of the study is to systematize all the previous measurements, and to extend the measurements to the sub-millimeter wavelength range. The spectrum of isocyanoacetonitrile has not been studied before. The rotational spectra of the two molecules was measured in the frequency range 150-660GHz using the Lille fast-scan spectrometer. The spectroscopic study was supported by high-level theoretical calculations on the structure of these molecules and their harmonic force field. Accurate frequency predictions for malononitrile and isocyanoacetonitrile were calculated on the basis of the analysis of their rotational spectra. The influence of the spin statistics on the intensities of the lines of malononitrile was taken into account. The provided line lists and sets of molecular parameters meet the needs of astrophysical searches for the two molecules.
- ID:
- ivo://CDS.VizieR/J/A+A/413/1177
- Title:
- Spectroscopy of N_2_D^+^ hyperfine structure
- Short Name:
- J/A+A/413/1177
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The analysis of the fully resolved Nitrogen hyperfine structure of N_2_D^+^ (1-0) observed toward L183, together with laboratory measurements of the same molecular transition, allowed an accurate determination of the hyperfine constants of both outer and inner Nitrogen. In addition, accurate rotational and centrifugal distortion constants were derived from submillimeter-wave laboratory measurements. The Tables list calculated hyperfine frequencies of J+1<--J transitions, with J in the range 1-11, which occur in the millimeter- and submillimeter-wave region.
- ID:
- ivo://CDS.VizieR/J/A+A/570/A12
- Title:
- Spectroscopy of 1,2-propanediol
- Short Name:
- J/A+A/570/A12
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Ethandiol is among the largest complex organic molecules detected in space thus far. It has been found in different types of molecular clouds. The two propanediol isomers are the next larger diols. Hence,they are viable candidates to be searched for in space. We want to provide sufficiently large and accurate sets of spectroscopic parameters of 1,2-propanediol to facilitate searches for this molecule at millimeter and longer submillimeter wavelengths. We recorded rotational spectra of 1,2-propanediol in three large frequency windows between 38 and 400GHz. We made extensive assignments for the three lowest energy conformers to yield spectroscopic parameters up to eighth order. Our present data will be helpful for identifying 1,2-propanediol at moderate submillimeter or longer wavelengths with radio telescope arrays such as ALMA, NOEMA, or EVLA. In particular, its detection with ALMA in sources, in which ethanediol was detected, appears to be promising.
- ID:
- ivo://CDS.VizieR/J/ApJS/213/28
- Title:
- Spectrum analysis of CrII
- Short Name:
- J/ApJS/213/28
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have made new observations of the spectrum of singly ionized chromium (CrII) in the region 2850-37900{AA} with the National Institute of Standards and Technology 2m Fourier transform spectrometer. These data extend our previously reported observations in the near-ultra-violet region. We present a comprehensive list of more than 5300 CrII lines classified as transitions among 456 even and 457 odd levels, 179 of which are newly located in this work. Using highly excited levels of the 3d^4^(^5^D)5g, 3d^4^(^5^D)6g, and 3d^4^(^5^D)6h configurations, we derive an improved ionization energy of 132971.02+/-0.12cm^-1^ (16.486305+/-0.000015eV).
