- ID:
- ivo://CDS.VizieR/J/ApJ/777/120
- Title:
- cm to submm spectra of H_2_C=CH-CH_2_NC
- Short Name:
- J/ApJ/777/120
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Organic isocyanides have an interesting astrochemistry and some of these molecules have been detected in the interstellar medium (ISM). However, rotational spectral data for this class of compounds are still scarce. We provide laboratory spectra of the four-carbon allyl isocyanide covering the full microwave region, thus allowing a potential astrophysical identification in the ISM. We assigned the rotational spectrum of the two cis (synperiplanar) and gauche (anticlinal) conformations of allyl isocyanide in the centimeter-wave region (4-18GHz), resolved its ^14^N nuclear quadrupole coupling (NQC) hyperfine structure, and extended the measurements into the millimeter and submillimeter-wave (150-900GHz) ranges for the title compound. Rotational constants for all the monosubstituted ^13^C and ^15^N isotopologues are additionally provided. Laboratory observations are supplemented with initial radioastronomical observations. Following analysis of an extensive dataset (>11000 rotational transitions), accurate ground-state molecular parameters are reported for the cis and gauche conformations of the molecule, including rotational constants, NQC parameters, and centrifugal distortion terms up to octic contributions. Molecular parameters have also been obtained for the two first excited states of the cis conformation, with a dataset of more than 3300 lines. The isotopic data allowed determining substitution and effective structures for the title compound. We did not detect allyl isocyanide either in the IRAM 30m line survey of Orion KL or in the PRIMOS survey toward SgrB2.
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Search Results
- ID:
- ivo://CDS.VizieR/J/ApJS/239/11
- Title:
- 800-13000cm^-1^ wide range OI spectra
- Short Name:
- J/ApJS/239/11
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Precision laboratory measurements are presented for 135 OI lines in the infrared (including 51 lines not measured previously in the laboratory) using time-resolved Fourier transform infrared spectroscopy in the 800-13000cm^-1^ region. The fine structure of some lines is observed for the first time. Using our linelist together with all relevant measurements from other works, we perform a re-optimization of OI level energies to obtain an internally consistent system of 2p^3^[^4^S]nl levels. Some OI level energies measured long ago are corrected. We also present a long list of oscillator strengths calculated with the help of quantum defect theory.
- ID:
- ivo://CDS.VizieR/J/A+A/469/783
- Title:
- Code for automatic determination of EW (ARES)
- Short Name:
- J/A+A/469/783
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a new automatic code (ARES) for determining equivalent widths of the absorption lines present in stellar spectra. We also describe its use for determining fundamental spectroscopic stellar parameters. The code is written in C++ based on the standard method of determining EWs and is available for the community. The code automates the manual procedure that the users normally carry out when using interactive routines such as the splot routine implemented in IRAF. Results.We test the code using both simulated and real spectra with different levels of resolution and noise and comparing its measurements to the
- ID:
- ivo://CDS.VizieR/J/A+A/399/795
- Title:
- Co III electron-impact broadening parameters
- Short Name:
- J/A+A/399/795
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In hot star atmospheres, the Stark broadening mechanism is the main pressure broadening mechanism. An interesting application where such a mechanism is of interest is the modeling and investigation of hot star spectra, stellar atmospheres and subphotospheric layers. Consequently, for the investigation and modeling of the Hg-Mn star and other type of hot star atmospheres, the Stark broadening parameters for Co III spectral lines may be of interest. Here we present Stark broadening data for 20 Co III spectral lines (from a^6^D-z^6^D^o^ and a^6^D-z^6^F^o^ Co III multiplets), as a function of temperature, calculated by using the modified semi-empirical approach. The importance of the electron-impact effect in the case of the Co III 194.98nm line for several stellar atmosphere models has been tested.
- ID:
- ivo://CDS.VizieR/J/A+AS/130/541
- Title:
- Co II oscillator strengths
- Short Name:
- J/A+AS/130/541
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In table 2 the log(gf) values for the 3d^8^+3d^7^ 4s-->3d^7^ 4p electric dipole (E1) transitions are given. This system is selected by cutting off energy values larger than 120,000cm^-1^ of both the even and the odd system in the final printing procedure; only log(gf) values larger than -3 are included. The first column of this table shows the wavelength obtained from the energy differences between the experimental level values. Wavelengths below 2000 Angstrom are given as vacuum wavelengths and above 2000 Angstrom as air wavelengths. The second column gives the log(gf) values followed by the J-value, energy value and the name of the lower (even) level. The first character of the level name designates the configuration number: for the even levels '1' refers to 3d^8^ and '2' to 3d^7^ 4s; for the odd levels '1' refers to 3d^7^ 4p. An '*' after the energy value indicates that the level is known, in which case the experimental level value is given. When unknown, the calculated energy value is given and used to approximate the wavelength. The A-values for the forbidden lines given in table 7 are restricted to the magnetic dipole (M1) and electric quadrupole (E2) transitions within the 3d^8^+3d^7^ 4s configurations, from levels with an energy of less than 50,000 cm^-1^ above the ground and with A-values larger than 10^-3^s^-1^. The level with the lower J-value is given first in the designation of the transition. The remaining columns are similar to the corresponding ones in table 2. The first character of the level name designates the configuration number: for the even levels '1' refers to 3d^8 and '2' to 3d^7 4s. An '*' after the energy value indicates that the level is known, in which case the experimental level value is given. When unknown, the calculated energy value is given and used to approximate the wavelength.
- ID:
- ivo://CDS.VizieR/J/A+AS/129/147
- Title:
- Co II radiative transition probabilities
- Short Name:
- J/A+AS/129/147
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Radiative transition probabilities have been calculated for the magnetic dipole (M1) and electric quadrupole (E2) transitions connecting the 47 metastable energy levels in the 3d^8^, 3d^7^ 4s and 3d^6^ 4s^2^ configurations in Co II. The most important configuration interaction (CI) and relativistic effects have been taken into account in the computations carried out with the help of the relativistic Hartree-Fock (HFR) method combined with a semi-empirical optimization of the radial parameters.
- ID:
- ivo://CDS.VizieR/J/ApJS/220/13
- Title:
- Co I transition probabilities
- Short Name:
- J/ApJS/220/13
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- New emission branching fraction measurements for 898 lines of the first spectrum of cobalt (Co I) are determined from hollow cathode lamp spectra recorded with the National Solar Observatory 1m Fourier transform spectrometer on Kitt Peak, AZ and a high-resolution echelle spectrometer. Published radiative lifetimes from laser induced fluorescence measurements are combined with the branching fractions to determine accurate absolute atomic transition probabilities for the 898 lines. Hyperfine structure (hfs) constants for levels of neutral Co in the literature are surveyed and selected values are used to generate complete hfs component patterns for 195 transitions of Co I. These new laboratory data are applied to determine the Co abundance in the Sun and metal-poor star HD 84937, yielding log{epsilon}(Co)=4.955+/-0.007 ({sigma}=0.059) based on 82 Co I lines and log{epsilon}(Co)=2.785+/-0.008 ({sigma}=0.065) based on 66 Co I lines, respectively. A Saha or ionization balance test on the photosphere of HD 84937 is performed using 16 UV lines of Co II, and good agreement is found with the Co I result in this metal-poor ([FeI/H]=-2.32, [FeII/H]=-2.32) dwarf star. The resulting value of [Co/Fe]=+0.14 supports a rise of Co/Fe at low metallicity that has been suggested in other studies.
- ID:
- ivo://CDS.VizieR/J/A+A/657/A121
- Title:
- Collisional effects in blue wing of Balmer-alpha
- Short Name:
- J/A+A/657/A121
- Date:
- 22 Feb 2022
- Publisher:
- CDS
- Description:
- In order to investigate the near wing of the Lyman-{alpha} line, accurate line profile calculations and molecular data are both required due to the existence of a close line satellite responsible for its asymmetrical shape. Lyman-{alpha} lines observed with the Cosmic Origin Spectograph (COS) on the Hubble Space Telescope (HST) show this peculiarity in the spectra of DBA and DA white dwarf stars. A similar asymmetrical shape in the blue wing can be predicted in the Balmer-{alpha} line of H perturbed by He and H atoms. In continuation with a very recent work on the Lyman-{alpha} line, where the n = 2 potential energies and transition dipole moments from the ground state were determined, we present new accurate H-He potential energies and electronic transition dipole moments involving the molecular states correlated with H(n=3)+He and their transition dipole moments with the states correlated with H(n=2)+He. Those new data and existing molecular data for H(n=2,3)-H are used to provide a theoretical investigation of the collisional effects in the blue wing of the Balmer-{alpha} line of H perturbed by He and H atoms. We note the consequences for the Balmer-{alpha} line shape in the physical conditions found in the cool atmosphere of DZA white dwarfs where helium densities may be as high as 10^21^cm^-3^. This study is undertaken with a unified theory of spectral line broadening valid at very high helium densities.
- ID:
- ivo://CDS.VizieR/J/A+A/531/A103
- Title:
- Collisional excitation of sulfur dioxide
- Short Name:
- J/A+A/531/A103
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present collisional rate coefficients for SO_2_ with ortho and para molecular hydrogen for the physical conditions prevailing in dark molecular clouds. Rate coefficients for the first 31 rotational levels of this species (energies up to 55K) and for temperatures between 5 and 30K are provided. We have found that these rate coefficients are about ten times more than those previously computed for SO_2_ with helium. We calculated the expected emission of the centimeter wavelength lines of SO_2_. We find that the transition connecting the metastable 2_02_ level with the 111 one is in absorption against the cosmic background for a wide range of densities. The 4_04_-3_13_ line is found to be inverted for densities below a few 10^4^cm^-3^. We observed the 1_11_-2_02_ transition with the 100m Green Bank Telescope towards some dark clouds. The line is observed, as expected, in absorption and provides an abundance of SO_2_ in these objects of a few 10^-10^. The potential use of millimeter lines of SO_2_ as tracers of the physical conditions of dark clouds is discussed.
- ID:
- ivo://CDS.VizieR/J/A+A/492/257
- Title:
- Collisional excitation of water in warm media
- Short Name:
- J/A+A/492/257
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The interpretation of water line emission from infrared and submillimetre observations requires a detailed knowledge of collisional rate coefficients over a wide range of levels and temperatures. We attempt to determine rotational and rovibrational rate coefficients for H_2_O colliding with both H_2_ and electrons in warm, molecular gas. Pure rotational rates are derived by extrapolating published data using a new method partly based on the information (phase space) theory of Levine and co-workers. Ro-vibrational rates are obtained using vibrational relaxation data available in the literature and by assuming a complete decoupling of rotation and vibration. Results. Rate coefficients were obtained for the lowest 824 ro-vibrational levels of H_2_O in the temperature range 200-5000K. Our data is expected to be accurate to within a factor of ~5 for the highest rates (>10^-11^cm^3^/s). Smaller rates, including the ro-vibrational ones, should be generally accurate to within an order of magnitude. As a first application of this data, we show that vibrationally excited water emission observed in evolved stars is expected to be at least partly excited by means of collisions.
