Volume 245, 2023

Experimental radiative cooling rates of a polycyclic aromatic hydrocarbon cation

Abstract

Several small Polycyclic Aromatic Hydrocarbons (PAHs) have been identified recently in the Taurus Molecular Cloud (TMC-1) using radio telescope observations. Reproducing the observed abundances of these molecules has been a challenge for astrochemical models. Rapid radiative cooling of PAHs by Recurrent Fluorescence (RF), the emission of optical photons from thermally populated electronically excited states, has been shown to efficiently stabilize small PAHs following ionization, augmenting their resilience in astronomical environments and helping to rationalize their observed high abundances. Here, we use a novel method to experimentally determine the radiative cooling rate of the cation of 1-cyanonaphthalene (C10H7CN, 1-CNN), the neutral species of which has been identified in TMC-1. Laser-induced dissociation rates and kinetic energy release distributions of 1-CNN cations isolated in a cryogenic electrostatic ion-beam storage ring are analysed to track the time evolution of the vibrational energy distribution of the initially hot ion ensemble as it cools. The measured cooling rate is in good agreement with the previously calculated RF rate coefficient. Improved measurements and models of the RF mechanism are needed to interpret astronomical observations and refine predictions of the stabilities of interstellar PAHs.

Graphical abstract: Experimental radiative cooling rates of a polycyclic aromatic hydrocarbon cation

Associated articles

Article information

Article type
Paper
Submitted
10 1 2023
Accepted
06 2 2023
First published
06 2 2023
This article is Open Access
Creative Commons BY license

Faraday Discuss., 2023,245, 352-367

Experimental radiative cooling rates of a polycyclic aromatic hydrocarbon cation

J. E. Navarro Navarrete, J. N. Bull, H. Cederquist, S. Indrajith, M. Ji, H. T. Schmidt, H. Zettergren, B. Zhu and M. H. Stockett, Faraday Discuss., 2023, 245, 352 DOI: 10.1039/D3FD00005B

This article is licensed under a Creative Commons Attribution 3.0 Unported Licence. You can use material from this article in other publications without requesting further permissions from the RSC, provided that the correct acknowledgement is given.

Read more about how to correctly acknowledge RSC content.

Social activity

Spotlight

Advertisements