AI 中文总结
本研究针对仲氢基质中的芳香腈开展实验室与理论研究，明确其光解离主要通道，产物可辅助解读JWST对光解离区芳香物质的中红外观测。
AI 中文摘要
受近期在金牛座分子云1中探测到多种芳香腈的启发，我们报告了对单取代和双取代氰基苯在固态仲氢基质中的振动光谱与光化学的实验室及理论研究。我们对比了苯甲腈（氰基苯）与三种二氰基苯异构体在193 nm激发下的光化学，还报告了氘代苯甲腈（d₅-氰基苯）的光化学，以此确定苯甲腈光解离的主要产物。所有腈类光解中观测到的主要产物为HCN和HNC，它们很可能由CN自由基从para-H₂中抽取氢原子生成，这表明主要光解离通道涉及环与腈基之间键的断裂，生成苯基（或氰基苯基）自由基与CN。我们还观测到与苯光解时类似的次级光产物，本研究结果或有助于解读詹姆斯·韦布空间望远镜（JWST）近期对光解离区中芳香物质的中红外观测。
英文摘要
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 cyano-substituted 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 (d$_5$-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-H$_2$ 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 mid-infrared observations of aromatics in photodissociation regions.
CommentsAccepted for publication in The Astrophysical Journal
