CONTEXT: The attachment of free electrons to polycondensed aromatic ring molecules (PAHs) is studied for the variety of these molecules with different numbers of condensed rings and over a broad range of electron temperatures, using a multichannel quantum scattering approach. The calculations of the relevant cross sections are used in turn to model the corresponding attachment rates for each of the systems under study, and these rates are parametrized as a function of temperature using a commonly employed expression for two-body processes in the interstellar medium (ISM). AIM: The scope of this work is to use first principles to establish the influence of chemical properties on the efficiency of the electron-attachment process for PAHs. METHODS: Quantum multichannel scattering methods are employed to generate the relevant cross sections, hence the attachment rates, using integral elastic cross sections computed over a broad range of relevant energies, from threshold up to 1000 K and linking the attachment to low-energy resonant collisions. RESULTS: The rates obtained for the present molecules are found to markedly vary within the test ensemble of the present work and to be lower than the earlier values used for the entire class of PAHs anions, when modelling their evolutions in ISM environments. The effects of such differences on the evolutions of chemical networks that include both PAH and PAH- species are analysed in some detail and related to previous calculations.
The Infrared Spectra of Very Large Irregular Polycyclic Aromatic Hydrocarbons (PAHs): Observational Probes of Astronomical PAH Geometry, Size and Charge
PDRs4All: XVIII. The evolution of the PAH ionisation and PAH size distribution across the Orion Bar
NASA Ames Research Center(NASA 艾姆斯研究中心);Department of Physics & Astronomy, The University of Western Ontario(韦仕敦大学物理与天文系);Institute for Earth and Space Exploration, The University of Western Ontario(韦仕敦大学地球与太空探索研究所);Carl Sagan Center, SETI Institute(SETI 研究所卡尔·萨根中心);Department of Astronomy, University of Michigan(密歇根大学天文学系);Institut de Recherche en Astrophysique et Planétologie, Université Toulouse III - Paul Sabatier, CNRS, CNES(图卢兹第三大学-保罗·萨巴蒂尔大学、法国国家科学研究中心、法国国家空间研究中心天体物理学和行星学研究所在);School of Physics, University of Hyderabad(海得拉巴大学物理学院);Department of Astronomy, The Ohio State University(俄亥俄州立大学天文学系);Institut d’Astrophysique Spatiale, Université Paris-Saclay, CNRS(巴黎南天体物理研究所)
A machine-learning-driven dataset of 144,111 polycyclic aromatic hydrocarbon infrared spectra for interpreting aromatic infrared bands
Guangxi University(广西大学);Laboratory for Relativistic Astrophysics, Department of Physics, Guangxi University(广西大学物理学院相对论天体物理实验室);Center for Applied Mathematics of Guangxi (Guangxi University)(广西应用数学中心(广西大学))