Hindering an ion-neutral reaction using vibrational excitation: The ν7 rovibrational band of c-C3H2+

Markus, Charles R.

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https://hdl.handle.net/2142/104286 Copy

Description

Title

Hindering an ion-neutral reaction using vibrational excitation: The ν7 rovibrational band of c-C3H2+

Author(s)

Markus, Charles R.

Contributor(s)

• Schlemmer, Stephan
• Brünken, Sandra
• Gauss, Jürgen
• Lipparini, Filippo
• Banhatti, Shreyak
• Schmid, Philipp C.
• Salomon, Thomas
• Asvany, Oskar

Issue Date

2019-06-19

Keyword(s)

Ions

Abstract

Ion-neutral reactions often occur rapidly at Langevin rate constants of $\sim 10^{-9}$~cm$^{3}$s$^{-1}$, even at low temperatures, which is why they are able to drive the chemistry of interstellar space. The reaction C$_3$H$_2^+ +$ H$_2\rightarrow $ C$_3$H$_3^+$ + H does not follow this trend, and has been known to occur at a much slower rate of $\sim 2\times 10^{-13}$~cm$^{3}$s$^{-1}$.\footnote{I. Savi\'c and D. Gerlich, \textit{Phys. Chem. Chem. Phys.}, \textbf{7}, 1026--1035, (2005).} It was recently observed that when C$_3$H$_2^+$ ions were resonantly excited by mid-IR light in a multipole ion trap held at 8~K, they were less likely to react with H$_2$ to form C$_3$H$_3^+$. Here, possible mechanisms behind this inhibited reaction process are discussed. Additionally, this effect can be utilized as a new form of action spectroscopy by counting the number of formed product ions as a function of the excitation wavelength, which was used here to measure 91 rovibrational transitions in the $\nu_7$ asymmetric C-H stretch band of the cyclic C$_3$H$_2^+$ isomer. The new frequencies were used to determine accurate molecular constants that are compared to high-level \textit{ab initio} calculations.

Publisher

International Symposium on Molecular Spectroscopy

Type of Resource

text

Language

eng

Permalink

http://hdl.handle.net/2142/104286

DOI

https://doi.org/10.15278/isms.2019.WF05

Copyright and License Information

Copyright 2019 Charles R. Markus

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