Formation Pathways of Cyanocoronene (C24H11CN) in the Interstellar Medium and its Detectability with JWST
4 affiliations
- 1Manipal Centre for Natural Sciences
- 2Manipal Academy of Higher Education
- 3Department of Physics
- 4Banaras Hindu University
Abstract
Cyanocoronene, the currently known largest cyano-substituted polycyclic aromatic hydrocarbon (PAH), has recently been discovered in the molecular cloud TMC-1. In this work, we investigate its possible formation pathways using density functional theory (DFT) together with multireference CASSCF and NEVPT2 quantum chemical calculations. Six distinct formation mechanisms are explored, including HAVA-type growth pathways as well as alternative bottomup routes. To facilitate astronomical searches, anharmonic infrared spectra of cyanocoronene are computed and compared with continuum-subtracted JWST/NIRSpec observations. Our calculations indicate that, among the bottom-up growth pathways considered, early incorporation of the nitrile group generally facilitates subsequent PAH growth, while direct cyanation of an already formed coronene framework is also energetically favorable, exhibiting a submerged barrier. Comparison of the theoretical spectra with the available JWST observations does not reveal any convincing spectral signatures attributable to cyanocoronene in the different astrophysical environments examined.
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BibTeX
@misc{vakuda2026formation,
title = {{Formation Pathways of Cyanocoronene (C24H11CN) in the Interstellar Medium and its Detectability with JWST}},
author = {Sharadhi Vakuda and Suranjan Shil and P. Shalima and Shivani Mishra and Amit Pathak and suranjan shil},
howpublished = {ChemRxiv},
year = {2026},
month = oct,
doi = {10.26434/chemrxiv.15010191/v1},
url = {https://chemrxiv.org/doi/full/10.26434/chemrxiv.15010191/v1},
note = {CC BY},
}
RIS
TY - UNPB
TI - Formation Pathways of Cyanocoronene (C24H11CN) in the Interstellar Medium and its Detectability with JWST
AU - Sharadhi Vakuda
AU - Suranjan Shil
AU - P. Shalima
AU - Shivani Mishra
AU - Amit Pathak
AU - suranjan shil
PY - 2026
DA - 2026/10/09
PB - ChemRxiv
DO - 10.26434/chemrxiv.15010191/v1
UR - https://chemrxiv.org/doi/full/10.26434/chemrxiv.15010191/v1
AB - Cyanocoronene, the currently known largest cyano-substituted polycyclic aromatic hydrocarbon (PAH), has recently been discovered in the molecular cloud TMC-1. In this work, we investigate its possible formation pathways using density functional theory (DFT) together with multireference CASSCF and NEVPT2 quantum chemical calculations. Six distinct formation mechanisms are explored, including HAVA-type growth pathways as well as alternative bottomup routes. To facilitate astronomical searches, anharmonic infrared spectra of cyanocoronene are computed and compared with continuum-subtracted JWST/NIRSpec observations. Our calculations indicate that, among the bottom-up growth pathways considered, early incorporation of the nitrile group generally facilitates subsequent PAH growth, while direct cyanation of an already formed coronene framework is also energetically favorable, exhibiting a submerged barrier. Comparison of the theoretical spectra with the available JWST observations does not reveal any convincing spectral signatures attributable to cyanocoronene in the different astrophysical environments examined.
ER -