- ID:
- ivo://CDS.VizieR/VI/127
- Title:
- High accuracy line list of HDO
- Short Name:
- VI/127
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A computed list of HD^16^O infrared transition frequencies and intensities is presented. The list, VTT, was produced using a discrete variable representation two-step approach for solving the rotation-vibration nuclear motions. The VTT line list contains almost 700 million transitions and can be used to simulate spectra of mono-deuterated water over the entire temperature range that are of importance for astrophysics. The line list can be used for deuterium-rich environments, such as the atmosphere of Venus, and to construct a possible "deuterium test" to distinguish brown dwarfs from planetary mass objects.
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Search Results
- ID:
- ivo://CDS.VizieR/J/A+A/578/A65
- Title:
- Highly rotationally excited HF collisional quenching
- Short Name:
- J/A+A/578/A65
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Collisional excitation rate coefficients play an important role in the dynamics of energy transfer in the interstellar medium. In particular, accurate rotational excitation rates are needed to interpret microwave and infrared observations of the interstellar gas for nonlocal thermodynamic equilibrium line formation. Theoretical cross sections and rate coefficients for collisional deexcitation of rotationally excited HF in the vibrational ground state are reported. The quantum-mechanical close-coupling approach implemented in the nonreactive scattering code MOLSCAT was applied in the cross section and rate coefficient calculations on an accurate 2D HF-He potential energy surface. Estimates of rate coefficients for H and H_2_ colliders were obtained from the HF-He collisional data with a reduced-potential scaling approach.
- ID:
- ivo://CDS.VizieR/J/A+AS/129/603
- Title:
- High-nl Rydberg states in C II, C III and C IV
- Short Name:
- J/A+AS/129/603
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Predicted term energies for values of the principal quantum number up to 30 and orbital quantum numbers l>=3 in C II, C III and C IV have been obtained using the Ritz and the polarization formulae. Wavelength predictions for lines involving these high-nl term energies together with the corresponding oscillator strengths, calculated by the HFR approach, are also reported in the present paper. Some astrophysical implications of these new atomic data are discussed by means of a comparison with the observed spectra of the planetary nebula NGC 7027.
- ID:
- ivo://CDS.VizieR/J/ApJS/211/28
- Title:
- High resolution EUV spectrum of N_2_
- Short Name:
- J/ApJS/211/28
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have analyzed high-resolution (FWHM=0.2{AA}) extreme-ultraviolet (EUV, 800-1350{AA}) laboratory emission spectra of molecular nitrogen excited by an electron impact at 20 and 100eV under (mostly) optically thin, single-scattering experimental conditions. A total of 491 emission features were observed from N_2_ electronic-vibrational transitions and atomic N I and N II multiplets and their emission cross sections were measured. Molecular emission was observed at vibrationally excited ground-state levels as high as v"=17, from the a^1^{Pi}_g_, b^1^{Pi}_u_, and b'^1^{Sigma}_u_^+^ excited valence states and the Rydberg series c'_n+1_^1^{Sigma}_u_^+^, c_n_^1^{Pi}_u_, and o_n_^1^{Pi}_u_ for n between 3 and 9. The frequently blended molecular emission bands were disentangled with the aid of a sophisticated and predictive quantum-mechanical model of excited states that includes the strong coupling between valence and Rydberg electronic states and the effects of predissociation. Improved model parameters describing electronic transition moments were obtained from the experiment and allowed for a reliable prediction of the vibrationally summed electronic emission cross section, including an extrapolation to unobserved emission bands and those that are optically thick in the experimental spectra. Vibrationally dependent electronic excitation functions were inferred from a comparison of emission features following 20 and 100eV electron-impact collisional excitation. The electron-impact-induced fluorescence measurements are compared with Cassini Ultraviolet Imaging Spectrograph observations of emissions from Titan's upper atmosphere.
- ID:
- ivo://CDS.VizieR/J/ApJ/847/67
- Title:
- High-resolution FIR spectrum of anti-vinyl alcohol
- Short Name:
- J/ApJ/847/67
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report a detailed analysis of the high-resolution far-infrared spectrum of anti-vinyl alcohol, which has been previously identified toward Sagittarius B2(N). The {nu}_15_ OH torsional fundamental investigated here is more than 200cm^-1^ removed from the next nearest vibration, making it practically unperturbed and ideal to help refine the ground state rotational constants that were previously determined from 25 microwave lines. We assigned 1335 lines within the {nu}_15_ fundamental centered at 261.5512cm^-1^, with J and K_a_ ranges of 1-59 and 0-16, respectively. The microwave and far-infrared line positions were fit with Watson-type A- and S-reduced Hamiltonians, with the inclusion of quartic and select sextic distortion terms. This resulted in a significant refinement of the ground state constants, in addition to the determination of the {nu}_15_=1 state constants for the first time. The spectroscopic parameters are in good agreement with the results from anharmonic coupled-cluster calculations, and should be useful in searches for rotationally and/or vibrationally warm anti-vinyl alcohol in interstellar molecular clouds.
- ID:
- ivo://CDS.VizieR/J/ApJ/833/L32
- Title:
- High-resolution infrared spectrum of HCl^+^
- Short Name:
- J/ApJ/833/L32
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The chloroniumyl cation, HCl^+^, has been recently identified in space from Herschel's spectra. A joint analysis of extensive vis-UV spectroscopy emission data together with a few high-resolution and high-accuracy millimeter-wave data provided the necessary rest frequencies to support the astronomical identification. Nevertheless, the analysis did not include any infrared (IR) vibration-rotation data. Furthermore, with the end of the Herschel mission, IR observations from the ground may be one of the few available means to further study this ion in space. In this work, we provide a set of accurate rovibrational transition wavenumbers, as well as a new and improved global fit of vis-UV, IR, and millimeter-wave spectroscopy laboratory data, that will aid in future studies of this molecule.
- ID:
- ivo://CDS.VizieR/J/ApJS/208/18
- Title:
- High-resolution spectrum of La and Ar
- Short Name:
- J/ApJS/208/18
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A high-resolution spectrum of lanthanum has been recorded by a Fourier Transform spectrometer in the wavelength range from 833nm to 1666nm (6000/cm to 12000/cm) using as light source a hollow cathode lamp operated with argon as the discharge carrier gas. In total, 2386 spectral lines were detected in this region, of which 555 lines could be classified as La I transitions and 10 lines as La II transitions. All La II transitions and 534 of these La I transitions were classified for the first time, and 6 of the La II transitions and 433 of the classified La I transitions appear to be new lines, which could not be found in the literature. The corresponding energy level data of classified lines are given. Additionally, 430 lines are assigned as Ar I lines and 394 as Ar II lines, of which 179 and 77, respectively, were classified for the first time. All 77 classified Ar II transitions as well as 159 of the classified Ar I transitions are new lines. Furthermore, the wavenumbers of 997 unclassified spectral lines were determined, 235 of which could be assigned as La lines, because of their hyperfine pattern. The remaining 762 lines may be either unclassified Ar lines or unresolved and unclassified La lines with only one symmetrical peak with an FWHM in the same order of magnitude as the Ar lines. The accuracy of the wavenumber for the classified lines with signal-to-noise-ratio higher than four is better than 0.006/cm which corresponds to an accuracy of 0.0004nm at 830nm and 0.0017nm at 1660nm, respectively.
- ID:
- ivo://CDS.VizieR/J/ApJS/240/4
- Title:
- High-temperature methane cross-sections
- Short Name:
- J/ApJS/240/4
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Spectra of hot methane were recorded using a tube furnace and a high-resolution Fourier transform spectrometer. We obtained experimental absorption spectra in the 1.85-1.11um near-infrared region at eight temperatures ranging from 295K up to 1000K. We have converted these into an atlas of absorption cross sections at each temperature for the methane tetradecad, icosad and triacontad polyads, excluding some spectral intervals either strongly contaminated by water or due to baseline fringes. On the theoretical side, the spectra were simulated from the ab initio-based Reims-Tomsk TheoReTS line list for the same experimental conditions. This line list has been constructed by global variational calculations from potential energy and dipole moment surfaces followed by empirical line position corrections deduced from previously published analyses. The comparisons showed very good overall agreement between observations and theory at high spectral resolution for the tetradecad and icosad and at medium or low resolution above this range. A full set of the theoretical absorption cross sections is also included. Detailed temperature dependence of the methane absorption enables the efficient method of remotely probing the temperature of distant astronomical objects based on a comparison of relative signals in carefully selected spectral intervals. This first combined experimental and theoretical easy-to-use cross-section library in the near-infrared should be of major interest for the interpretation of current and future astronomical observations up to a resolving power of 100000-300000 in the range 6400-7600cm^-1^ and a resolving power of 5000-10000 in the higher wavenumber range up to 9000cm^-1^.
- ID:
- ivo://CDS.VizieR/J/A+A/627/A65
- Title:
- HNCO, CH3CN and HCOOCH3 partition functions
- Short Name:
- J/A+A/627/A65
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We emphasize that the completeness of the partition function, i.e. the use of a converged partition function at the typical temperature range of the survey, is very important to decrease the uncertainty on this quantity and thus to derive reliable interstellar molecular densities. In that context, we will show how the use of different approximations for the rovibrational partition function together with some interpolation and/or extrapolation procedures may affect the estimate of the interstellar molecular column density. For that purpose, we will apply the partition function calculations to astronomical observations performed with the IRAM-30m telescope towards the NGC7538-IRS1 source of the two following N-bearing molecules: isocyanic acid (HNCO, a quasilinear molecule) and methyl cyanide (CH_3_CN, a symmetric top molecule). The case of methyl formate (HCOOCH_3_), which is an asymmetric top O-bearing molecule which contains an internal rotor will also be discussed. Our analysis shows that the use of different partition function approximations leads to relative differences in the resulting column densities in the range of 9% up to 43%. Thus, we expect that this work turns out to be relevant for surveys of sources with temperatures higher than 300 K and to observations in the infrared.
- ID:
- ivo://CDS.VizieR/J/MNRAS/454/2292
- Title:
- H_3_O^+^ and D_3_O^+^ rotational transitions
- Short Name:
- J/MNRAS/454/2292
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The mass sensitivity of the vibration-rotation-inversion transitions of H_3_^16^O^+^, H_3_^18^O^+^, and D_3_^16^O^+^ is investigated variationally using the nuclear motion program trove (Yurchenko, Thiel & Jensen 2007JMoSp.245..126Y). The calculations utilize new high-level ab initio potential energy and dipole moment surfaces. Along with the mass dependence, frequency data and Einstein A coefficients are computed for all transitions probed. Particular attention is paid to the {Delta}|k|=3 and {Delta}|k-l|=3 transitions comprising the accidentally coinciding |J, K=0, v_2_=0^+^> and |J, K=3, v_2_=0^-^> rotation-inversion energy levels. The newly computed probes exhibit sensitivities comparable to their ammonia and methanol counterparts, thus demonstrating their potential for testing the cosmological stability of the proton-to-electron mass ratio. The theoretical trove results are in close agreement with sensitivities obtained using the non-rigid and rigid inverter approximate models, confirming that the ab initio theory used in the present study is adequate.
