Direct observation of long-lived cyanide anions in superexcited states

The cyanide anion (CN − ) has been identified in cometary coma, interstellar medium, planetary atmosphere and circumstellar envelopes, but its origin and abundance are still disputed. An isolated CN − is stabilized in the vibrational states up to ν = 17 of the electronic ground-state 1 Σ + , but it...

Full description

Saved in:
Bibliographic Details
Published in:Communications chemistry 2021-02, Vol.4 (1), p.13-6, Article 13
Main Authors: Gao, Xiao-Fei, Xie, Jing-Chen, Li, Hao, Meng, Xin, Wu, Yong, Tian, Shan Xi
Format: Article
Language:English
Subjects:
639/638/169/894
639/638/440/949
Anions
Atomic energy levels
Chemistry
Chemistry and Materials Science
Chemistry/Food Science
Comet heads
Comets
Cyanogen
Electron attachment
Electron states
Electrons
Interstellar chemistry
Interstellar matter
Interstellar space
Planetary atmospheres
Stellar envelopes
Vibrational states
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:The cyanide anion (CN − ) has been identified in cometary coma, interstellar medium, planetary atmosphere and circumstellar envelopes, but its origin and abundance are still disputed. An isolated CN − is stabilized in the vibrational states up to ν = 17 of the electronic ground-state 1 Σ + , but it is not thought to survive in the electronic or vibrational states above the electron autodetachment threshold, namely, in superexcited states. Here we report the direct observation of long-lived CN − yields of the dissociative electron attachment to cyanogen bromide (BrCN), and confirm that some of the CN − yields are distributed in the superexcited vibrational states ν ≥ 18 ( 1 Σ + ) or the superexcited electronic states 3 Σ + and 3 Π. The triplet state can be accessed directly in the impulsive dissociation of BrCN − or by an intersystem transition from the superexcited vibrational states of CN − . The exceptional stability of CN − in the superexcited states profoundly influences its abundance and is potentially related to the production of other compounds in interstellar space. Cyanide anions exist in interstellar space, but the vibrationally or electronically excited states above the electron autodetachment threshold of CN - are assumed to have no contributions to cosmic CN - . Here, the authors report long-lived, superexcited CN - from the dissociative electron attachment to cyanogen bromide.
ISSN:2399-3669
2399-3669
DOI:10.1038/s42004-021-00450-0