Astrochemical model to study the abundances of branched carbon-chain molecules in a hot molecular core with realistic binding energies

Abstract

Straight-chain (normal-propyl cyanide, n - C3H7CN) and branched-chain (iso-propyl cyanide, i - C3H7CN) alkyl cyanides are recently identified in the massive star-forming regions (Sgr B2(N) and Orion). These branched-chain molecules indicate that the key amino acids (side-chain structures) may also be present in a similar region. The process by which this branching could propagate towards the higher-order (butyl cyanide, C4H9CN) is an active field of research. Since the grain catalysis process could have formed a major portion of these species, considering a realistic set of binding energies are indeed essential. We employ quantum chemical calculations to estimate the binding energy of these species considering water as a substrate because water is the principal constituent of this interstellar ice. We find significantly lower binding energy values for these species than were previously used. It is noticed that the use of realistic binding energy values can significantly change the abundance of these species. The branching is more favorable for the higher-order alkyl cyanides with the new binding energies. With the inclusion of our new binding energy values and one essential destruction reaction (i - C3H7CN + H -> CH3C(CH3)CN + H2, having an activation barrier of 947 K), abundances of t - C4H9CN dramatically increased.

arXiv comment16 pages, 16 figures, 8 tables, accepted for publication in MNRAS

References in corpus (37)

• Observations of the Icy Universe
• The UMIST database for astrochemistry 2012
• A KInetic Database for Astrochemistry (KIDA)
• Detection of the Aromatic Molecule Benzonitrile ($c$-C${}_6$H${}_5$CN) in the Interstellar Medium
• Detection of Two Interstellar Polycyclic Aromatic Hydrocarbons via Spectral Matched Filtering
• A three-phase chemical model of hot cores: the formation of glycine
• Discovery of the Interstellar Chiral Molecule Propylene Oxide (CH${}_3$CHCH${}_2$O)
• Pure hydrocarbon cycles in TMC-1: Discovery of ethynyl cyclopropenylidene, cyclopentadiene and indene
• Detection of a branched alkyl molecule in the interstellar medium: iso-propyl cyanide
• Discovery of the Pure Polycyclic Aromatic Hydrocarbon Indene ($c$-C${}_9$H${}_8$) with GOTHAM Observations of TMC-1
• Exploring Molecular Complexity with ALMA (EMoCA): Deuterated complex organic molecules in Sagittarius B2(N2)
• The dust temperature distribution in prestellar cores
• A new modified-rate approach for gas-grain chemical simulations
• Discovery in space of ethanolamine, the simplest phospholipid head group
• The complex chemistry of hot cores in Sagittarius B2(N): Influence of cosmic-ray ionization and thermal history
• Discovery of two isomers of ethynyl cyclopentadiene in TMC-1: Abundances of CCH and CN derivatives of hydrocarbon cycles
• Exploring molecular complexity with ALMA (EMoCA): Simulations of branched carbon-chain chemistry in Sgr B2(N)
• First detection of the pre-biotic molecule glycolonitrile (HOCH2CN) in the interstellar medium
• An Approach to Estimate the Binding energy of Interstellar Species
• Propargylimine in the laboratory and in space: millimetre-wave spectroscopy and first detection in the ISM
• Interstellar Detection of 2-Cyanocyclopentadiene, C${}_5$H${}_5$CN, a Second Five-Membered Ring Toward TMC-1
• Identification of pre-biotic molecules containing Peptide-like bond in a hot molecular core, G10.47+0.03
• Search for Interstellar monohydric Thiols
• Composition and evolution of Interstellar Grain mantle under the effects of photo-dissociation
• Formation of water and methanol in star forming molecular clouds
• Chemical modeling for predicting the abundances of certain aldimines and amines in hot cores
• Effects of Initial Condition and Cloud Density on the Composition of the Grain Mantle
• Methyl Acetate and its singly deuterated isotopomers in the interstellar medium
• Deuterium enrichment of the interstellar grain mantle
• Deuterium Enrichment of the Interstellar Medium
• Exploring molecular complexity with ALMA (EMoCA): Complex isocyanides in Sgr B2(N)
• Chemical complexity of phosphorous bearing species in various regions of the Interstellar medium
• Chemical and radiative transfer modeling of Propylene Oxide
• The Possibility of Forming Propargyl Alcohol in the Interstellar Medium
• Effect of binding energies on the encounter desorption
• C5H9N Isomers: Pointers to Possible Branched Chain Interstellar Molecules
• A Systematic Study on the Absorption Features of Interstellar Ices in Presence of Impurities

Cited by in corpus (5)

• Detection of Interstellar $E$-1-cyano-1,3-butadiene in GOTHAM Observations of TMC-1
• Assessing realistic binding energies of some essential interstellar radicals with amorphous solid water. A fully quantum chemical approach
• A comprehensive rotational study of astronomical iso-pentane within 84 to 111 GHz
• Metallic species in interstellar medium: Astrochemical modeling
• Research on the Interstellar Medium and Star Formation in the Galaxy: An Indian Perspective