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The hydroxyl radical, OH, is an important component of many natural and technological plasmas but there is little available information on processes involving its collisions with low-energy electrons. Low-energy electron collisions with OH…

Atomic Physics · Physics 2019-09-04 Kalyan Chakrabarti , Vincenzo Laporta , Jonathan Tennyson

We report on laboratory measurements of molecular hydrogen formation and recombination on an olivine slab as a function of surface temperature under conditions relevant to those encountered in the interstellar medium. On the basis of our…

Astrophysics · Physics 2009-10-30 V. Pirronello , O. Biham , C. Liu , L. Shen , G. Vidali

Even though water is the main constituent in interstellar icy mantles, its chemical origin is not well understood. Three different formation routes have been proposed following hydrogenation of O, O2, or O3, but experimental evidence is…

Astrophysics · Physics 2009-11-13 S. Ioppolo , H. M. Cuppen , C. Romanzin , E. F. van Dishoeck , H. Linnartz

Context: Molecular hydrogen ($\rm{H_2}$) is crucial in galaxy formation and evolution, serving as the main fuel for star formation (SF). In metal-enriched environments, $\rm{H_2}$ primarily forms on interstellar dust grain surfaces.…

Experimental results on the formation of molecular hydrogen on amorphous silicate surfaces are presented for the first time and analyzed using a rate equation model. The energy barriers for the relevant diffusion and desorption processes…

Gas-phase processes were long thought to be the key formation mechanisms for complex organic molecules in star-forming regions. However, recent experimental and theoretical evidence has cast doubt on the efficiency of such processes.…

Astrophysics · Physics 2009-11-13 Robin T. Garrod , Susanna L. Widicus Weaver , Eric Herbst

Semi-empirical molecular dynamics is used to simulate several gaseous atomic hydrogen interactions with hydrocarbon grains in space: recoil, adsorption, diffusion, chemisorption and recombination into molecular hydrogen. Their probabilities…

Astrophysics · Physics 2009-11-10 Renaud Papoular

In order to improve the understanding of the low temperature combustion of ethanol, high-level ab initio calculations were performed for elementary reactions involving hydroxyethylperoxy radicals. These radicals come from the addition of…

Chemical Physics · Physics 2009-04-21 René Fournet , Pierre-Alexandre Glaude , Roda Bounaceur , Michel Molière

We study the evolution of molecular hydrogen on the grain surfaces and in the gas phase using both the rate equation (which tracks the average number of molecules) and the master equation (which tracks the expectation values of molecules).…

Astrophysics · Physics 2009-11-10 K. Acharyya , Sandip K. Chakrabarti , S. Chakrabarti

A study of a reacting boundary layer flow with heat transfer at conditions typical for configurations at elevated pressures has been performed using a set of direct numerical simulations. Effects of wall temperatures are investigated,…

Fluid Dynamics · Physics 2021-02-16 Nikolaos Perakis , Oskar Haidn , Matthias Ihme

Methanol (CH3OH) is thought to form on interstellar ice dust via successive hydrogenation reactions. The reaction between CH3 and OH radicals could also conceivably generate methanol at temperatures above approximately 20 K, at which…

Astrophysics of Galaxies · Physics 2026-01-12 Arisa Iguchi , Hiroshi Hidaka , Atsuki Ishibashi , Masashi Tsuge , Yasuhiro Oba , Naoki Watanabe

We investigate the formation of the recently detected HNSO molecule using quantum chemical calculations on ices and astrochemical models in tandem. Our results indicate that HNSO is efficiently produced on grain surfaces through reactions…

We use a set of cosmological simulations combined with radiative transfer calculations to investigate the distribution of neutral hydrogen in the post-reionization Universe. We assess the contributions from the metagalactic ionizing…

Cosmology and Nongalactic Astrophysics · Physics 2013-08-27 Alireza Rahmati , Andreas H. Pawlik , Milan Raičević , Joop Schaye

We modelled recent observations of UV absorption of HD and \HH\ in the Milky Way and toward damped/sub-damped Lyman alpha systems at z=0.18 and z $>$ 1.7. N(HD)/N(\HH) ratios reflect the separate self-shieldings of HD and \HH\ and the…

Astrophysics of Galaxies · Physics 2015-06-23 H. S. Liszt

As part of a far-infrared (FIR) spectral scan with Herschel/PACS, we present the first detection of the hydroxyl radical (OH) towards the Orion Bar photodissociation region (PDR). Five OH rotational Lambda-doublets involving energy levels…

Astrophysics of Galaxies · Physics 2015-05-28 J. R. Goicoechea , C. Joblin , A. Contursi , O. Berne , J. Cernicharo , M. Gerin , J. Le Bourlot , E. A. Bergin , T. A. Bell , M. Rollig

Many astrochemical models today explicitly consider the species that comprise the bulk of interstellar dust grain ice-mantles separately from those in the top few monolayers. Bombardment of these ices by ionizing radiation - whether in the…

Astrophysics of Galaxies · Physics 2019-05-29 Christopher N. Shingledecker , Anton Vasyunin , Eric Herbst , Paola Caselli

The efficiency of silicon solar cells gradually decreases in various environments, with humidity being a key factor contributing to this decline through moisture-induced degradation (MID) involving multiple mechanisms including encapsulant…

Materials Science · Physics 2026-03-13 Bo Li , Feifei Zhang , Yu Pang , Jinyu Hu , Huiyan Zhao , Guocai Liu , Chao He , Xingtao An

The energy to desorb atomic oxygen from an interstellar dust grain surface, $E_{\rm des}$, is an important controlling parameter in gas-grain models; its value impacts the temperature range over which oxygen resides on a dust grain.…

Astrophysics of Galaxies · Physics 2015-06-23 Jiao He , Jianming Shi , Tyler Hopkins , Gianfranco Vidali , Michael J. Kaufman

Explaining the formation pathways of amides on ice-grain mantels is crucial to understanding the prebiotic chemistry in an interstellar medium. In this computational study, we explore different radical-neutral formation pathways for some of…

Astrophysics of Galaxies · Physics 2024-07-10 Gabriela Silva-Vera , Giulia M. Bovolenta , Namrata Rani , Sebastian Vera , Stefan Vogt-Geisse

Understanding the degradation mechanisms of aliphatic polymers by thermal oxidation and radio-oxidation is very important in order to assess their lifetime in a variety of industrial applications. We focus here on polyethylene as a…

Soft Condensed Matter · Physics 2021-07-01 Yunho Ahn , Xavier Colin , Guido Roma