The Study Of Direct D Atom Incorporation In Radicals At Low Temperature Probed By Chirped Pulse Mm-wave Spectroscopy

Dias, Nureshan

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https://hdl.handle.net/2142/111334 Copy

Description

Title

The Study Of Direct D Atom Incorporation In Radicals At Low Temperature Probed By Chirped Pulse Mm-wave Spectroscopy

Author(s)

Dias, Nureshan

Contributor(s)

• Suits, Arthur
• Broderick, Bernadette M.
• Gurusinghe, Ranil

Issue Date

2021-06-23

Keyword(s)

Dynamics and kinetics

Abstract

We are utilizing chirped pulse mm-wave spectroscopy in quasi-uniform supersonic flows at low temperature to probe isomer-specific product branching and kinetics. Earlier we have studied the photodissociation of the propargyl radical and monitored the branching between the three isomers of \chem{C_3H_2} and noted efficient conversion of \chem{H_2CCC} and HCCCH to the cyclic form induced by H addition/elimination, a process termed H-catalyzed isomerization. We will show that by adding a D atom source to the flow we observe very efficient D atom enrichment in the products through an analogous process of D addition/H elimination to \chem{C_3H_2} isomers occurring at 40K or below. Cyclic \chem{C_3HD} is the only deuterated isomer observed consistent with the expected addition/elimination yielding the lowest energy product. In the high-density region of the flow, we also observe singly deuterated propyne formed following stabilization of the D + \chem{C_3H_3} adduct, and both isotopomers \chem{CH_2DCCH} and \chem{CH_3CCD} are observed in nearly equal abundance. The implications of this for deuterium fractionation in astrochemical environments will be further discussed with the support of monodeuterated dark cloud model developed by Millar et al. Recent results for low temperature radical-radical reactions relevant to planetary atmospheres will also be highlighted.

Publisher

International Symposium on Molecular Spectroscopy

Type of Resource

Text

Language

eng

Permalink

http://hdl.handle.net/2142/111334

DOI

10.15278/isms.2021.WC11

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