Document Type
Article
Publication Date
9-21-2026
Abstract
Motivated by recent detections of several aromatic nitriles in Taurus Molecular Cloud 1, we report laboratory and theoretical investigations of the vibrational spectroscopy and photochemistry of singly and doubly cyanosubstituted benzene in solid para-hydrogen matrices. We compare the photochemistry of cyanobenzene (benzonitrile) and three dicyanobenzene isomers initiated by excitations at 193 nm. In addition, we report the photochemistry of deuterated cyanobenzene (d5-cyanobenzene), enabling us to determine the major products produced during the cyanobenzene photodissociation. The major products observed in the photolysis of all the nitriles are HCN and HNC, which are likely produced by hydrogen abstraction from para-hydrogen by the CN radical. This indicates that the major photodissociation channel involves cleavage of the bond between the ring and the nitrile group, forming the phenyl (or cyanophenyl) radical + CN. We observe secondary photoproducts similar to those found during benzene photolysis. Our findings may aid the interpretation of recent JWST midinfrared observations of aromatics in photodissociation regions.
Recommended Citation
Sam McGrath et al 2026 ApJ 1009 98 https://doi.org/10.3847/1538-4357/ae9752
Copyright
The authors
Creative Commons License
This work is licensed under a Creative Commons Attribution 4.0 License.
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Comments
This article was originally published in The Astrophysical Journal, volume 1009, issue 2, in 2026. https://doi.org/10.3847/1538-4357/ae9752