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Polycyclic Aromatic Hydrocarbon (PAH) emission features dominate the mid-infrared spectra of star-forming galaxies and can be useful to calibrate star formation rates and diagnose ionized states of grains. However, the PAH 3.3 micron…

We have carried out an investigation of the chemical evolution of gas in different carbon-rich circumstellar environments. Previous studies have tended to invoke terrestrial flame chemistries, based on acetylene (C2H2) combustion to model…

Astrophysics of Galaxies · Physics 2015-06-15 Harpreet Dhanoa , Jonathan M. C. Rawlings

This study theoretically predicts the specific Polycyclic Aromatic Hydrocarbon (PAH) molecules to reproduce both astronomically observed Infrared Bands (IR) and Diffuse Interstellar Bands (DIB). In our recent paper, we could reproduce IR by…

Astrophysics of Galaxies · Physics 2023-11-23 Norio Ota

Propargyl alcohol (HC2CH2OH, PA) has yet to be observed in the interstellar medium (ISM) although one of its stable isomers, propenal (CH2CHCHO), has already been detected in Sagittarius B2(N) with the 100-meter Green Bank Telescope in the…

Astrophysics of Galaxies · Physics 2017-01-24 Prasanta Gorai , Ankan Das , Liton Majumdar , Sandip Kumar Chakrabarti , Bhalamurugan Sivaraman , Eric Herbst

Planet-forming disks of gas and dust around young stars contain polycyclic aromatic hydrocarbons (PAHs). We aim to characterize how the charge state of PAHs can be used as a probe of flows of gas through protoplanetary gaps. In this…

Solar and Stellar Astrophysics · Physics 2015-06-18 K. M. Maaskant , M. Min , L. B. F. M. Waters , A. G. G. M. Tielens

A novel theoretical method is developed to study the polycyclic aromatic hydrocarbon - diffuse interstellar band (PAH-DIB) hypothesis. In this method, a computer program is used to enumerate all PAH molecules with up to a specific number of…

Astrophysics · Physics 2007-05-23 Xiaofeng Tan

Hydrogen peroxide (H2O2) formation rates in a proton exchange membrane (PEM) fuel cell anode and cathode were estimated as a function of humidity and temperature by studying the oxygen reduction reaction (ORR) on a rotating ring disc…

We investigate the presence of silicon atoms adsorbed on the surface of interstellar polycyclic aromatic hydrocarbons (PAHs) to form SiPAH pi-complexes. We use quantum chemistry calculations to obtain structural, thermodynamic and mid-IR…

Astrophysics · Physics 2009-11-13 B. Joalland , A. Simon , C. J. Marsden , C. Joblin

Cyclopentadiene (CPD) is an important intermediate in the combustion of fuel and the formation of aromatics. In the present study, the kinetics and thermodynamic properties for hydrogen abstraction and addition with CPD, and the related…

Computational Physics · Physics 2019-10-25 Qian Mao , Liming Cai , Heinz Pitsch

We calibrate the integrated luminosity from the polycyclic aromatic hydrocarbon (PAH) features at 6.2\micron, 7.7\micron\ and 11.3\micron\ in galaxies as a measure of the star-formation rate (SFR). These features are strong (containing as…

Astrophysics of Galaxies · Physics 2016-02-17 Heath V. Shipley , Casey Papovich , George H. Rieke , Michael J. I. Brown , John Moustakas

We demonstrate that the formation of negative hydrogen ions (H-) occurs in a wide class of atomic and molecular collisions. In our experiments, H- emission from hydroxyl cations and acetone molecules was observed in keV-energy collisions.…

We develop the theory of radiative association of an atom and a diatomic molecule within a close-coupling framework. We apply it to the formation of H$_3^-$ after the low energy collision (below 0.5 eV) of H$_2$ with H$^-$. Using recently…

Atomic Physics · Physics 2015-05-27 M. Ayouz , Raphael Lopes , Maurice Raoult , Olivier Dulieu , V. Kokoouline

We report new computational and experimental evidence of an efficient and astrochemically relevant formation route to formaldehyde (H$_2$CO). This simplest carbonylic compound is central to the formation of complex organics in cold…

We have obtained new STIS/HST spectra to search for structure in the ultraviolet interstellar extinction curve, with particular emphasis on a search for absorption features produced by polycyclic aromatic hydrocarbons (PAHs). The presence…

We study the formation of C$_{18}$H and C$_{18}$H$_2$ by irradiating a cyclo[$18$]carbon molecule with atomic and molecular hydrogen at impact energy, $E$, in the range of 0.5-25 eV. We utilize the density-functional tight-binding method to…

Recent experimental results about the formation of molecular hydrogen on astrophysically relevant surfaces under conditions close to those encountered in the interstellar medium are analyzed using rate equations. The parameters of the rate…

Astrophysics · Physics 2009-10-31 N. Katz , I. Furman , O. Biham , V. Pirronello , G. Vidali

We present a new method to accurately describe the ionization fraction and the size distribution of polycyclic aromatic hydrocarbons (PAHs) within astrophysical sources. To this purpose, we have computed the mid-infrared emission spectra of…

Astrophysics of Galaxies · Physics 2020-03-18 A. Maragkoudakis , E. Peeters , A. Ricca

Polycyclic aromatic hydrocarbons (PAHs) appear to be ubiquitous in terrestrial atmosphere as well as in the interstellar medium (ISM). In the astrophysical context presence of PAHs is interpreted by the observations of mid-IR emission bands…

Chemical Physics · Physics 2019-03-26 Rashmi Singh , Shantanu Rastogi

Mixtures of polycylic aromatic hydrocarbons (PAHs) have been produced by means of laser pyrolysis. The main fraction of the extracted PAHs were primarily medium-sized, up to a maximum size of 38 carbon atoms per molecule. The use of…

Instrumentation and Methods for Astrophysics · Physics 2011-01-24 M. Steglich , C. Jäger , G. Rouillé , F. Huisken , H. Mutschke , Th. Henning
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