- ID:
- ivo://CDS.VizieR/J/ApJ/813/12
- Title:
- Empirical methane (CH_4_) line list
- Short Name:
- J/ApJ/813/12
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Hot methane is found in many "cool" sub-stellar astronomical sources including brown dwarfs and exoplanets, as well as in combustion environments on Earth. We report on the first high-resolution laboratory absorption spectra of hot methane at temperatures up to 1200K. Our observations are compared to the latest theoretical spectral predictions and recent brown dwarf spectra. The expectation that millions of weak absorption lines combine to form a continuum, not seen at room temperature, is confirmed. Our high-resolution transmittance spectra account for both the emission and absorption of methane at elevated temperatures. From these spectra, we obtain an empirical line list and continuum that is able to account for the absorption of methane in high temperature environments at both high and low resolution. Great advances have recently been made in the theoretical prediction of hot methane, and our experimental measurements highlight the progress made and the problems that still remain.
Number of results to display per page
Search Results
- ID:
- ivo://CDS.VizieR/J/ApJ/820/117
- Title:
- Energies & IR intensities of amide polymers
- Short Name:
- J/ApJ/820/117
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report on the formation of organic amide polymers via carbonyl-amino group linkages in carbon monoxide and ammonia bearing energetically processed ices of astrophysical relevance. The first group comprises molecules with one carboxyl group and an increasing number of amine moieties starting with formamide (45 u), urea (60 u), and hydrazine carboxamide (75 u). The second group consists of species with two carboxyl (58 u) and up to three amine groups (73 u, 88 u, and 103 u). The formation and polymerization of these linkages from simple inorganic molecules via formamide und urea toward amide polymers is discussed in an astrophysical and astrobiological context. Our results show that long chain molecules, which are closely related to polypeptides, easily form by energetically processing simple, inorganic ices at very low temperatures and can be released into the gas phase by sublimation of the ices in star-forming regions. Our experimental results were obtained by employing reflectron time-of-flight mass spectroscopy, coupled with soft, single photon vacuum ultraviolet photoionization; they are complemented by theoretical calculations.
- ID:
- ivo://CDS.VizieR/J/ApJS/223/3
- Title:
- Energies & radiative transition from ArXII to ZnXXIV
- Short Name:
- J/ApJS/223/3
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Combined relativistic configuration interaction and many-body perturbation calculations are performed for the 359 fine-structure levels of the 2s^2^2p^3^, 2s2p^4^, 2p^5^, 2s^2^2p^2^3l, 2s2p^3^3l, 2p^4^3l, and 2s^2^2p^2^4l configurations in N-like ions from Ar XII to Zn XXIV. Complete and consistent data sets of energies, wavelengths, radiative rates, oscillator strengths, and line strengths for all possible electric dipole, magnetic dipole, electric quadrupole, and magnetic quadrupole transitions among the 359 levels are given for each ion. The present work significantly increases the amount of accurate data for ions in the nitrogen-like sequence, and the accuracy of the energy levels is high enough to enable the identification and interpretation of observed spectra involving the n=3, 4 levels, for which experimental values are largely scarce. Meanwhile, the results should be of great help for modeling and diagnosing astrophysical and fusion plasmas.
- ID:
- ivo://CDS.VizieR/J/A+A/473/995
- Title:
- Energy levels and radiative rates in Co XI
- Short Name:
- J/A+A/473/995
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In this paper we report calculations for energy levels and radiative rates for transitions in Co XI. The General purpose Relativistic Atomic Structure Package GRASP and the Flexible Atomic Code FAC have been adopted for the calculations of energy levels and radiative rates. Energies for the lowest 287 levels of Co XI, including those among the (1s^2^2s^2^2p^6^) 3s^2^3p^5^, 3s3p^6^, 3s^2^3p^4^3d, 3s3p^5^3d, 3s^2^3p^3^3d^2^, and 3s^2^3p^4^4s configurations, are reported. Additionally, radiative rates and oscillator strengths are reported for all electric dipole (E1) transitions with f>=10^-5^ among these levels, and similar results for magnetic dipole (M1), electric quadrupole (E2), and magnetic quadrupole (M2) transitions are reported only for those with f>=10^-8^. Comparisons are made with the available results in the literature, and the accuracy of the present data is assessed. Finally, lifetimes for all excited levels are also listed, although measurements are presently available for only one of these.
- ID:
- ivo://CDS.VizieR/J/ApJS/212/11
- Title:
- Energy levels and spectral lines of FeV
- Short Name:
- J/ApJS/212/11
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This paper, combining a critical compilation with new calculations, provides revised comprehensive lists of recommended energy levels, observed spectral lines, and transition probabilities in the spectrum of quadruply ionized iron (Fe V). The new level optimization made in this work is based on critically assessed uncertainties of about 2000 wavelengths previously measured with grating spectrographs. For 80% of energy levels, relative uncertainties have been reduced by a factor of three on average, compared with previously reported uncertainties. For 65% of observed lines, uncertainties of the new Ritz wavelengths are smaller than those of observed wavelengths by a factor of four on average.
- ID:
- ivo://CDS.VizieR/J/ApJS/205/14
- Title:
- Energy levels and spectral lines of MnII
- Short Name:
- J/ApJS/205/14
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This compilation revises the previously recommended list of energy levels of singly ionized manganese (Mn II) and provides a comprehensive list of observed spectral lines and transition probabilities in this spectrum. The new level optimization takes into account critically assessed uncertainties of measured wavelengths and includes about a hundred high-precision wavelengths determined by laser spectroscopy and Fourier transform techniques. Uncertainties of 63% of energy levels and 74% of Ritz wavelengths are reduced by a factor of three on average.
- ID:
- ivo://CDS.VizieR/J/ApJS/215/26
- Title:
- Energy levels and transition rates of C-like ions
- Short Name:
- J/ApJS/215/26
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Based on systematic calculations using a combined relativistic configuration interaction and a many-body perturbation theory (MBPT) approach, we provide a complete and consistent data set for 46 levels belonging to the 2s^2^2p^2^, 2s2p^3^, 2p^4^, 2s^2^2p3s, 2s^2^2p3p, and 2s^2^2p3d configurations in C-like ions with 13<=Z<=36. The data set includes energy levels as well as electric dipole, magnetic dipole, electric quadrupole, and magnetic quadrupole transition properties. Extensive comparisons with available observed and calculated results are made and indicate that the present MBPT calculations are highly accurate. The present data set can be used reliably for many purposes, such as the line identification of observed spectra, and modeling and diagnostics of astrophysical and fusion plasmas.
- ID:
- ivo://CDS.VizieR/J/ApJS/238/34
- Title:
- Energy levels for L-shell ions of sulfur & argon
- Short Name:
- J/ApJS/238/34
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Calculated level energies for valence and K-vacancy states are provided for the ion series SVII-SXIV and ArIX-ArXVI. The calculations were performed with the relativistic Multi-Reference Moller-Plesset Perturbation Theory method (MR-MP). The data set includes all the level energies with configurations 1s^2^2(s,p)^q^, 1s^2^2(s,p)^q-1^nl, 1s^1^2(s,p)^q+1^, 1s^1^2(s,p)^q^nl, 2(s,p)^q+2^, and 2(s,p)^q+1^nl, where 1<=q<=8, n<=5, and l<=3. We have compared our results with data from the National Institute of Standards and Technology (NIST) online database and with previous calculations. The average deviation of valence level energies ranges from 0.16eV in Ne-like ions to 0.01eV in Li-like ions, showing that the present MR-MP valence level energies are highly accurate. In the case of K-vacancy states, the deviation is generally below 0.3eV for Li-like SXIV and ArXVI. The deviation for K-vacancy energies in other L-shell ions (Be-, B-, C-, N-, and O-like Ar ions) is higher but likely because the NIST-recommended values have a higher uncertainty. The data set includes many n=4 and n=5 valence and K-vacancy levels in L-shell ions of S and Ar that have not been previously reported. The data can be used for line identification and modeling of L-shell ions of S and Ar in astrophysical and laboratory-generated plasmas, and as energy references in the absence of more accurate laboratory measurements.
- ID:
- ivo://CDS.VizieR/J/ApJS/231/19
- Title:
- Energy levels of ionized vanadium (V II)
- Short Name:
- J/ApJS/231/19
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The energy levels, observed spectral lines, and transition probabilities of singly ionized vanadium, V II, have been compiled. The experimentally derived energy levels belong to the configurations 3d^4^, 3d^3^ns (n=4,5,6), 3d^3^np, and 3d^3^nd (n=4,5), 3d^3^4f, 3d^2^4s^2^, and 3d^2^4s4p. Also included are values for some forbidden lines that may be of interest to the astrophysical community. Experimental Lande g-factors and leading percentages for the levels are included when available, as well as Ritz wavelengths calculated from the energy levels. Wavelengths and transition probabilities are reported for 3568 and 1896 transitions, respectively. From the list of observed wavelengths, 407 energy levels are determined. The observed intensities, normalized to a common scale, are provided. From the newly optimized energy levels, a revised value for the ionization energy is derived, 118,030(60)cm^-1^, corresponding to 14.634(7)eV. This is 130cm^-1^ higher than the previously recommended value from Iglesias+ (1988, Publ. Inst. Opt. Madrid 47 1).
- ID:
- ivo://CDS.VizieR/J/ApJS/231/18
- Title:
- Energy levels & spectral lines of vanadium (V I)
- Short Name:
- J/ApJS/231/18
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The energy levels, observed spectral lines, and transition probabilities of the neutral vanadium atom, V I, have been compiled. Also included are values for some forbidden lines that may be of interest to the astrophysical community. Experimental Lande g-factors and leading percentage compositions for the levels are included where available, as well as wavelengths calculated from the energy levels (Ritz wavelengths). Wavelengths are reported for 3985 transitions, and 549 energy levels are determined. The observed relative intensities normalized to a common scale are provided.
