Laboratory Synthesis of Molecular Hydrogen on Surfaces of Astrophysical Interest

Pirronello, V.; Liu, Chi; Shen, Liyong; Vidali, Gianfranco

doi:10.1086/310464

Cited by 174 publications

(229 citation statements)

References 19 publications

Supporting

Mentioning

225

Contrasting

Unclassified

Order By: Relevance

“…Garrod et al (2007) have previously proposed a formula in their models that can be used to describe the chemical desorption (or reactive desorption). They derived the probability of A24, page 4 of 6 Bergeron et al (2008); (c) Al-Halabi & van Dishoeck (2007), Amiaud et al (2007); (d) Pirronello et al (1997); (e) Amiaud et al (2006) for low coverage; ( f ) Minissale et al (2015); (g) Dulieu et al (2013); (h) Speedy et al (1996), Fraser et al (2001 energy derived of 5800 K with pre-factor of 10 15 s −1 here corrected to have a pre-factor of 10 12 s −1 ; (i) Noble et al (2012a); ( (2)) that include division between the degree of freedom and the fraction of kinetic energy after bounce ( is mass dependent). In red we show the equal share of energy and the constant value of .…”

Section: Theoretical Estimate Of the Desorption Efficiencymentioning

confidence: 99%

Dust as interstellar catalyst

Minissale

Dulieu

Cazaux

et al. 2015

A&A

184

227

View full text Add to dashboard Cite

Context. The presence of dust in the interstellar medium has profound consequences on the chemical composition of regions where stars are forming. Recent observations show that many species formed onto dust are populating the gas phase, especially in cold environments where UV-and cosmic-ray-induced photons do not account for such processes. Aims. The aim of this paper is to understand and quantify the process that releases solid species into the gas phase, the so-called chemical desorption process, so that an explicit formula can be derived that can be included in astrochemical models. Methods. We present a collection of experimental results of more than ten reactive systems. For each reaction, different substrates such as oxidized graphite and compact amorphous water ice were used. We derived a formula for reproducing the efficiencies of the chemical desorption process that considers the equipartition of the energy of newly formed products, followed by classical bounce on the surface. In part II of this study we extend these results to astrophysical conditions. Results. The equipartition of energy correctly describes the chemical desorption process on bare surfaces. On icy surfaces, the chemical desorption process is much less efficient, and a better description of the interaction with the surface is still needed. Conclusions. We show that the mechanism that directly transforms solid species into gas phase species is efficient for many reactions.

show abstract

Section: Theoretical Estimate Of the Desorption Efficiencymentioning

confidence: 99%

Dust as interstellar catalyst

Minissale

Dulieu

Cazaux

et al. 2015

A&A

184

227

View full text Add to dashboard Cite

show abstract

“…Burke and Hollenbach (1983), Hollenbach and McKee (1989), and Buch and Zhang (1991) make theoretical estimates of the T and T gr dependence of S and . Lin and Vidali (1996) and Pirronello et al (1997aPirronello et al ( , 1997b have recently reported new laboratory measurements of S.…”

Section: H 2 Formation Destruction and Heatingmentioning

confidence: 99%

Photodissociation regions in the interstellar medium of galaxies

Hollenbach

Tielens²

1999

Rev. Mod. Phys.

751

712

View full text Add to dashboard Cite

The interstellar medium of galaxies is the reservoir out of which stars are born and into which stars inject newly created elements as they age. The physical properties of the interstellar medium are governed in part by the radiation emitted by these stars. Far-ultraviolet (6 eVϽh Ͻ13.6 eV) photons from massive stars dominate the heating and influence the chemistry of the neutral atomic gas and much of the molecular gas in galaxies. Predominantly neutral regions of the interstellar medium in which the heating and chemistry are regulated by far ultraviolet photons are termed PhotoDissociation Regions (PDRs). These regions are the origin of most of the non-stellar infrared (IR) and the millimeter and submillimeter CO emission from galaxies. The importance of PDRs has become increasingly apparent with advances in IR and submillimeter astronomy. The IR emission from PDRs includes fine structure lines of C, C ϩ , and O; rovibrational lines of H 2 ; rotational lines of CO; broad mid-IR features of polycyclic aromatic hydrocarbons; and a luminous underlying IR continuum from interstellar dust. The transition of H to H 2 and C ϩ to CO occurs within PDRs. Comparison of observations with theoretical models of PDRs enables one to determine the density and temperature structure, the elemental abundances, the level of ionization, and the radiation field. PDR models have been applied to interstellar clouds near massive stars, planetary nebulae, red giant outflows, photoevaporating planetary disks around newly formed stars, diffuse clouds, the neutral intercloud medium, and molecular clouds in the interstellar radiation field-in summary, much of the interstellar medium in galaxies. Theoretical PDR models explain the observed correlations of the [CII] 158 m with the CO Jϭ1 -0 emission, the CO Jϭ1 -0 luminosity with the interstellar molecular mass, and the [CII] 158 m plus [OI] 63 m luminosity with the IR continuum luminosity. On a more global scale, PDR models predict the existence of two stable neutral phases of the interstellar medium, elucidate the formation and destruction of star-forming molecular clouds, and suggest radiation-induced feedback mechanisms that may regulate star formation rates and the column density of gas through giant molecular clouds. [S0034-6861(99)01001-6] CONTENTS

show abstract

“…In the experiments of Pirronnello et al, [16][17][18] a model grain surface was irradiated with a beam of H and D atoms and HD molecules were produced. A temperature scan was performed, and the results were analyzed in terms of rate equations.…”

Section: Resultsmentioning

confidence: 99%

Grain Formation Modulated by Molecular Hydrogen Evaporation in the Interstellar Medium

2009

View full text Add to dashboard Cite

A mechanism for grain growth and formation in the interstellar medium is proposed. In this mechanism, hydrogen molecules act as moderators. The process begins when they physisorb to the surface of the grain. Then, when a collision with a heavy atom occurs, the bonding energy is carried away by the evaporation of hydrogen molecules. Estimates are made of the number of hydrogen molecules bound to the surface of a grain that would be sufficient to facilitate this mechanism at 13 K for amorphous carbon and 8 K for a silicate grain.

show abstract

Laboratory Synthesis of Molecular Hydrogen on Surfaces of Astrophysical Interest

Cited by 174 publications

References 19 publications

Dust as interstellar catalyst

Dust as interstellar catalyst

Photodissociation regions in the interstellar medium of galaxies

Grain Formation Modulated by Molecular Hydrogen Evaporation in the Interstellar Medium

Contact Info

Product

Resources

About