1 Ocak 2023 Dergi makalesi Açık Erişim

Rocha, Carlos M. R.; Roncero, Octavio; Bulut, Niyazi; Zuchowski, Piotr; Navarro-Almaida, David; Fuente, Asuncion; Wakelam, Valentine; Loison, Jean-Christophe; Roueff, Evelyne; Goicoechea, Javier R.; Esplugues, Gisela; Beitia-Antero, Leire; Caselli, Paola; Lattanzi, Valerio; Pineda, Jaime; Le Gal, Romane; Rodriguez-Baras, Marina; Riviere-Marichalar, Pablo

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{
  "@context": "https://schema.org/", 
  "@id": 270264, 
  "@type": "ScholarlyArticle", 
  "creator": [
    {
      "@type": "Person", 
      "affiliation": "Leiden Univ, Lab Astrophys, Leiden Observ, POB 9513, NL-2300 RA Leiden, Netherlands", 
      "name": "Rocha, Carlos M. R."
    }, 
    {
      "@type": "Person", 
      "affiliation": "CSIC, Inst Fis Fundamental IFF, Serrano 123, Madrid 28006, Spain", 
      "name": "Roncero, Octavio"
    }, 
    {
      "@type": "Person", 
      "affiliation": "Firat Univ, Dept Phys, TR-23169 Elazig, Turkiye", 
      "name": "Bulut, Niyazi"
    }, 
    {
      "@type": "Person", 
      "affiliation": "Nicolaus Copernicus Univ Torun, Inst Phys, Fac Phys Astron & Informat, Grudziadzka 5, PL-87100 Torun, Poland", 
      "name": "Zuchowski, Piotr"
    }, 
    {
      "@type": "Person", 
      "affiliation": "Univ Paris Saclay, Dept Astrophys DAp, CEA, AIM, F-91191 Gif Sur Yvette, France", 
      "name": "Navarro-Almaida, David"
    }, 
    {
      "@type": "Person", 
      "affiliation": "Observ Astron Nacl IGN, C Alfonso XII 2, Madrid 28014, Spain", 
      "name": "Fuente, Asuncion"
    }, 
    {
      "@type": "Person", 
      "affiliation": "Univ Bordeaux, Lab Astrophys Bordeaux, B18N, CNRS, Allee Geoffroy St Hilaire, F-33615 Pessac, France", 
      "name": "Wakelam, Valentine"
    }, 
    {
      "@type": "Person", 
      "affiliation": "Univ Bordeaux, Inst Sci Mol ISM, CNRS, 351 Cours Liberat, F-33400 Talence, France", 
      "name": "Loison, Jean-Christophe"
    }, 
    {
      "@type": "Person", 
      "affiliation": "Sorbonne Univ, Observ Paris, Univ PSL, CNRS,LERMA, F-92190 Meudon, France", 
      "name": "Roueff, Evelyne"
    }, 
    {
      "@type": "Person", 
      "affiliation": "CSIC, Inst Fis Fundamental IFF, Serrano 123, Madrid 28006, Spain", 
      "name": "Goicoechea, Javier R."
    }, 
    {
      "@type": "Person", 
      "affiliation": "Observ Astron Nacl IGN, C Alfonso XII 2, Madrid 28014, Spain", 
      "name": "Esplugues, Gisela"
    }, 
    {
      "@type": "Person", 
      "affiliation": "Observ Astron Nacl IGN, C Alfonso XII 2, Madrid 28014, Spain", 
      "name": "Beitia-Antero, Leire"
    }, 
    {
      "@type": "Person", 
      "affiliation": "Max Planck Inst Extraterr Phys, Ctr Astrochem Studies, Giessenbachstr 1, D-85748 Garching, Germany", 
      "name": "Caselli, Paola"
    }, 
    {
      "@type": "Person", 
      "affiliation": "Max Planck Inst Extraterr Phys, Ctr Astrochem Studies, Giessenbachstr 1, D-85748 Garching, Germany", 
      "name": "Lattanzi, Valerio"
    }, 
    {
      "@type": "Person", 
      "affiliation": "Max Planck Inst Extraterr Phys, Ctr Astrochem Studies, Giessenbachstr 1, D-85748 Garching, Germany", 
      "name": "Pineda, Jaime"
    }, 
    {
      "@type": "Person", 
      "name": "Le Gal, Romane"
    }, 
    {
      "@type": "Person", 
      "affiliation": "Observ Astron Nacl IGN, C Alfonso XII 2, Madrid 28014, Spain", 
      "name": "Rodriguez-Baras, Marina"
    }, 
    {
      "@type": "Person", 
      "affiliation": "Observ Astron Nacl IGN, C Alfonso XII 2, Madrid 28014, Spain", 
      "name": "Riviere-Marichalar, Pablo"
    }
  ], 
  "datePublished": "2023-01-01", 
  "description": "<p>Context. Carbon monosulphide (CS) is among the few sulphur-bearing species that have been widely observed in all environments, including in the most extreme, such as diffuse clouds. Moreover, CS has been widely used as a tracer of the gas density in the interstellar medium in our Galaxy and external galaxies. Therefore, a complete understanding of its chemistry in all environments is of paramount importance for the study of interstellar matter.</p>\n<p>Aims. Our group is revising the rates of the main formation and destruction mechanisms of CS. In particular, we focus on those involving open-shell species for which the classical capture model might not be sufficiently accurate. In this paper, we revise the rates of reactions CH + S -&gt; CS + H and C-2 + S -&gt; CS + C. These reactions are important CS formation routes in some environments such as dark and diffuse warm gas.</p>\n<p>Methods. We performed ab initio calculations to characterize the main features of all the electronic states correlating to the open shell reactants. For CH+S, we calculated the full potential energy surfaces (PESs) for the lowest doublet states and the reaction rate constant with a quasi-classical method. For C-2+S, the reaction can only take place through the three lower triplet states, which all present deep insertion wells. A detailed study of the long-range interactions for these triplet states allowed us to apply a statistic adiabatic method to determine the rate constants.</p>\n<p>Results. Our detailed theoretical study of the CH + S -&gt; CS + H reaction shows that its rate is nearly independent of the temperature in a range of 10-500 K, with an almost constant value of 5.5 x 10(-11) cm(3) s(-1) at temperatures above 100 K. This is a factor of about 2-3 lower than the value obtained with the capture model. The rate of the reaction C-2 + S -&gt; CS + C does depend on the temperature, and takes values close to 2.0 x 10(-10) cm(3) s-(1) at low temperatures, which increase to similar to 5.0 x 10(-10) cm(3) s(-1) for temperatures higher than 200 K. In this case, our detailed modeling - taking into account the electronic and spin states - provides a rate that is higher than the one currently used by factor of approximately 2.</p>\n<p>Conclusions. These reactions were selected based on their inclusion of open-shell species with many degenerate electronic states, and, unexpectedly, the results obtained in the present detailed calculations provide values that differ by a factor of about 2-3 from the simpler classical capture method. We updated the sulphur network with these new rates and compare our results in the prototypical case of TMC1 (CP). We find a reasonable agreement between model predictions and observations with a sulphur depletion factor of 20 relative to the sulphur cosmic abundance. However, it is not possible to fit the abundances of all sulphur-bearing molecules better than a factor of 10 at the same chemical time.</p>", 
  "headline": "Gas phase Elemental abundances in Molecular cloudS (GEMS) VIII. Unlocking the CS chemistry: The CH plus S \u2192 CS + H and C<sub>2</sub> + S \u2192 CS plus C reactions", 
  "identifier": 270264, 
  "image": "https://aperta.ulakbim.gov.tr/static/img/logo/aperta_logo_with_icon.svg", 
  "license": "http://www.opendefinition.org/licenses/cc-by", 
  "name": "Gas phase Elemental abundances in Molecular cloudS (GEMS) VIII. Unlocking the CS chemistry: The CH plus S \u2192 CS + H and C<sub>2</sub> + S \u2192 CS plus C reactions", 
  "url": "https://aperta.ulakbim.gov.tr/record/270264"
}