Astrochemical model to study the abundances of branched carbon-chain molecules in a hot molecular core with realistic binding energies
Journal article, 2022

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 favourable 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 + H-2 , having an activation barrier of 947 K), abundances of t - C4H9CN dramatically increased.

ISM: abundances

ISM: molecules

molecular processes

astrochemistry

ISM: evolution

Author

Satyam Srivastav

Banaras Hindu University

Milan Sil

S.N. Bose National Centre for Basic Sciences (SNBNCBS)

Prasanta Gorai

Chalmers, Space, Earth and Environment, Astronomy and Plasmaphysics

Amit Pathak

Banaras Hindu University

Bhalamurugan Sivaraman

Physical Research Laboratory

Ankan Das

Institute of Astronomy Space and Earth Science

Monthly Notices of the Royal Astronomical Society

0035-8711 (ISSN) 1365-2966 (eISSN)

Vol. 515 3 3524-3538

Subject Categories

Biochemistry and Molecular Biology

Theoretical Chemistry

Organic Chemistry

DOI

10.1093/mnras/stac1904

More information

Latest update

8/26/2022