Reaction Networks For Interstellar Chemical Modelling: Improvements and Challenges

Abstract

We survey the current situation regarding chemical modelling of the synthesis of molecules in the interstellar medium. The present state of knowledge concerning the rate coefficients and their uncertainties for the major gas-phase processes -- ion-neutral reactions, neutral-neutral reactions, radiative association, and dissociative recombination -- is reviewed. Emphasis is placed on those reactions that have been identified, by sensitivity analyses, as 'crucial' in determining the predicted abundances of the species observed in the interstellar medium. These sensitivity analyses have been carried out for gas-phase models of three representative, molecule-rich, astronomical sources: the cold dense molecular clouds TMC-1 and L134N, and the expanding circumstellar envelope IRC +10216. Our review has led to the proposal of new values and uncertainties for the rate coefficients of many of the key reactions. The impact of these new data on the predicted abundances in TMC-1 and L134N is reported. Interstellar dust particles also influence the observed abundances of molecules in the interstellar medium. Their role is included in gas-grain, as distinct from gas-phase only, models. We review the methods for incorporating both accretion onto, and reactions on, the surfaces of grains in such models, as well as describing some recent experimental efforts to simulate and examine relevant processes in the laboratory. These efforts include experiments on the surface-catalysed recombination of hydrogen atoms, on chemical processing on and in the ices that are known to exist on the surface of interstellar grains, and on desorption processes, which may enable species formed on grains to return to the gas-phase.

Accepted for publication in Space Science Reviews

References in corpus (21)

• Complex Chemistry in Star-Forming Regions: An Expanded Gas-Grain Warm-up Chemical Model
• Formation of methyl formate and other organic species in the warm-up phase of hot molecular cores
• Non-thermal desorption from interstellar dust grains via exothermic surface reactions
• Understanding adsorption of hydrogen atoms on graphene
• Polycylcic Aromatic Hydrocarbons (PAH's) in dense cloud chemistry
• Laboratory evidence for efficient water formation in interstellar ices
• Photodesorption of water ice: a molecular dynamics study
• Formation of hydrogen peroxide and water from the reaction of cold hydrogen atoms with solid oxygen at 10K
• The effect of uncertainties on chemical models of dark clouds
• Oxygen Chemistry in the Circumstellar Envelope of the Carbon-Rich Star IRC+10216
• A new modified-rate approach for gas-grain chemical simulations
• Desorption of CO and O2 interstellar ice analogs
• Density-enhanced gas and dust shells in a new chemical model for IRC+10216
• Cold CO in circumstellar disks: On the effects of photodesorption and vertical mixing
• Chemistry in Protoplanetary Disks: A Sensitivity Analysis
• H-atom bombardment of CO2, HCOOH and CH3CHO containing ices
• Mobility of D atoms on porous amorphous water ice surfaces under interstellar conditions
• Monte Carlo simulations of H2 formation on stochastically heated grains
• Kinetic Monte Carlo Studies of Hydrogen Abstraction from Graphite
• A sensitivity study of the neutral-neutral reactions C + C3 and C + C5 in cold dense interstellar clouds
• A kinetic Monte Carlo study of desorption of H2 from graphite (0001)

Cited by in corpus (67)

• The UMIST database for astrochemistry 2012
• A KInetic Database for Astrochemistry (KIDA)
• Photodissociation and photoionisation of atoms and molecules of astrophysical interest
• The 2014 KIDA network for interstellar chemistry
• Interstellar water chemistry: from laboratory to observations
• Chemistry of Dark Clouds: Databases, Networks, and Models
• Astrochemistry and compositions of planetary systems
• KROME - a package to embed chemistry in astrophysical simulations
• On the reservoir of sulphur in dark clouds : chemistry and elemental abundance reconciled
• VULCAN: an Open-Source, Validated Chemical Kinetics Python Code for Exoplanetary Atmospheres
• Chemical evolution of turbulent protoplanetary disks and the Solar nebula
• Atom addition reactions in interstellar ice analogues
• Oxygen depletion in dense molecular clouds: a clue to a low O2 abundance?
• The IRAM-30m line survey of the Horsehead PDR: II. First detection of the l-C3H+ hydrocarbon cation
• The interstellar gas-phase chemistry of HCN and HNC
• Thermal desorption characteristics of CO, O2 and CO2 on non-porous water, crystalline water and silicate surfaces at sub-monolayer and multilayer coverages
• Interstellar chemistry of nitrogen hydrides in dark clouds
• A Simple and Accurate Network for Hydrogen and Carbon Chemistry in the ISM
• Elemental nitrogen partitioning in dense interstellar clouds
• The interstellar chemistry of H2C3O isomers
• The gas-phase chemistry of carbon chains in dark cloud chemical models
• New method to study ion-molecule reactions at low temperatures and application to the H${}_2^{+}$ + H${}_2$ $\to$ H${}_3^{+}$ + H reaction
• Polysulfanes on interstellar grains as a possible reservoir of interstellar sulphur
• The chemistry of disks around T Tauri and Herbig Ae/Be stars
• The ALMA-PILS survey: First detection of nitrous acid (HONO) in the interstellar medium
• Survival of interstellar molecules to prestellar dense core collapse and early phases of disk formation
• Revised Models of Interstellar Nitrogen Isotopic Fractionation
• Efficient Surface Formation Route of Interstellar Hydroxylamine through NO Hydrogenation II: the multilayer regime in interstellar relevant ices
• Carbon-Chain Chemistry in the Interstellar Medium
• Review of OCS gas-phase reactions in dark cloud chemical models
• Isocyanogen formation in the cold interstellar medium
• Photodissociation and chemistry of N${}_2$ in the circumstellar envelope of carbon-rich AGB stars
• Nautilus multi-grain model: Importance of cosmic-ray-induced desorption in determining the chemical abundances in the ISM
• Methyl Acetate and its singly deuterated isotopomers in the interstellar medium
• Interactions of adsorbed CO${}_2$ on water ice at low temperatures
• The complex organic molecular content in the L1517B starless core
• Machine Learning of Interstellar Chemical Inventories
• A new model of the chemistry of ionizing radiation in solids: CIRIS
• Non-Equilibrium Chemistry and Destruction of CO by X-ray Flares
• Multipole-moment effects in ion-molecule reactions at low temperatures: part I -- Ion-dipole enhancement of the rate coefficients of the He${}^{+}$ + NH${}_3$ and He${}^{+}$ + ND${}_3$ reactions at collision energies near $0$ K
• Sulphur and carbon isotopes towards Galactic centre clouds
• Destruction of dimethyl ether and methyl formate by collisions with He${}^{+}$
• A new protonated molecule discovered in TMC-1: HCCNCH+
• The efficiency of photodissociation for molecules in interstellar ices
• Is there any linkage between interstellar aldehyde and alcohol?
• Thermal Rate Coefficients for the Astrochemical Process C + CH${}^{+}$ $\to$ C${}_2^{+}$ + H by Ring Polymer Molecular Dynamics
• A Mini-Chemical Scheme with Net Reactions for 3D GCMs I.: Thermochemical Kinetics
• The Possibility of Forming Propargyl Alcohol in the Interstellar Medium
• Chemical and radiative transfer modeling of Propylene Oxide
• Influence of galactic arm scale dynamics on the molecular composition of the cold and dense ISM I. Observed abundance gradients in dense clouds
• Denoising Diffusion Probabilistic Models to Predict the Density of Molecular Clouds
• Sensitivity Analysis of Aromatic Chemistry to Gas-Phase Kinetics in a Dark Molecular Cloud Model
• Recommended Thermal Rate Coefficients for the C + H${}_3^{+}$ Reaction and Some Astrochemical Implications
• Towards the impact of GMC collisions on the star formation rate
• A sequential acid-base (SAB) mechanism in the interstellar medium: The emergence of cis formic acid in dark molecular clouds
• Chemical compositions of five Planck cold clumps
• A recent update of gas-phase chemical reactions and molecular lines in CLOUDY: its effects on millimeter and sub-millimeter molecular line predictions
• Low-Temperature Kinetics for the N + NO reaction: Experiment Guides the Way
• The HIFI spectral survey of AFGL 2591 (CHESS). III. Chemical structure of the protostellar envelope
• HYACINTH: HYdrogen And Carbon chemistry in the INTerstellar medium in Hydro simulations
• Impact of an Active Sgr A* on the Synthesis of Water and Organic Molecules Throughout the Milky Way
• Spin-orbit transitions in the N${}^{+}$(${}^3{P}_{J_A}$) + H${}_2$ $\to$ NH${}^{+}$($X^2\Pi$, ${}^4{\Sigma }^{-}$)+ H(${}^{2}S$) reaction, using adiabatic and mixed quantum-adiabatic statistical approaches
• Electron collision studies on the CH${}_2^{+}$ molecular ion
• Rotational Excitation of Vinyl Cyanide by Collisions with Helium Atoms at Low Temperature
• Chemical properties of two dense cores in a Planck Galactic Cold Clump G168.72-15.48
• Chemical evolution of a protoplanetary disk
• A Large-scale Approach to Modelling Molecular Biosignatures: The Diatomics