Direct D-atom Incorporation in Radicals: An Overlooked Pathway for Deuterium Fractionation
Direct D-H exchange in radicals is investigated in a quasi-uniform flow employing chirped-pulse millimeter-wave spectroscopy. Inspired by the H-atom catalyzed isomerization of C _3 H _2 reported in our previous study, D-atom reactions with the propargyl (C _3 H _3 ) radical and its photoproducts wer...
| Main Authors: | , , , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
IOP Publishing
2023-01-01
|
| Series: | The Astrophysical Journal |
| Subjects: | |
| Online Access: | https://doi.org/10.3847/1538-4357/acac1d |
| _version_ | 1797697256744288256 |
|---|---|
| author | Nureshan Dias Ranil M. Gurusinghe Bernadette M. Broderick Tom J Millar Arthur G. Suits |
| author_facet | Nureshan Dias Ranil M. Gurusinghe Bernadette M. Broderick Tom J Millar Arthur G. Suits |
| author_sort | Nureshan Dias |
| collection | DOAJ |
| description | Direct D-H exchange in radicals is investigated in a quasi-uniform flow employing chirped-pulse millimeter-wave spectroscopy. Inspired by the H-atom catalyzed isomerization of C _3 H _2 reported in our previous study, D-atom reactions with the propargyl (C _3 H _3 ) radical and its photoproducts were investigated. We observed very efficient D-atom enrichment in the photoproducts through an analogous process of D addition/H elimination to C _3 H _2 isomers occurring at 40 K or below. Cyclic C _3 HD is the only deuterated isomer observed, consistent with the expected addition/elimination yielding the lowest energy product. The other expected addition/elimination product, deuterated propargyl, is not directly detected, although its presence is inferred by the observations in the latter part of the flow. There, in the high-density region of the flow, we observed both isotopomers of singly deuterated propyne attributed to stabilization of the H+C _3 H _2 D or D+C _3 H _3 adducts. The implications of these observations for the deuterium fractionation of hydrocarbon radicals in astrochemical environments is discussed with the support of a monodeuterated chemical kinetic model. |
| first_indexed | 2024-03-12T03:37:45Z |
| format | Article |
| id | doaj.art-6bf764c851d74c29bb3494b4f26005e0 |
| institution | Directory Open Access Journal |
| issn | 1538-4357 |
| language | English |
| last_indexed | 2024-03-12T03:37:45Z |
| publishDate | 2023-01-01 |
| publisher | IOP Publishing |
| record_format | Article |
| series | The Astrophysical Journal |
| spelling | doaj.art-6bf764c851d74c29bb3494b4f26005e02023-09-03T13:07:58ZengIOP PublishingThe Astrophysical Journal1538-43572023-01-0194417710.3847/1538-4357/acac1dDirect D-atom Incorporation in Radicals: An Overlooked Pathway for Deuterium FractionationNureshan Dias0Ranil M. Gurusinghe1Bernadette M. Broderick2Tom J Millar3https://orcid.org/0000-0001-5178-3656Arthur G. Suits4https://orcid.org/0000-0001-5405-8361Department of Chemistry, University of Missouri , Columbia MO 65211, USA ; suitsa@missouri.eduDepartment of Chemistry, University of Missouri , Columbia MO 65211, USA ; suitsa@missouri.eduDepartment of Chemistry, University of Missouri , Columbia MO 65211, USA ; suitsa@missouri.eduSchool of Mathematics and Physics, Queen’s University Belfast , University Road, Belfast BT7 1NN, UK ; Tom.Millar@qub.ac.ukDepartment of Chemistry, University of Missouri , Columbia MO 65211, USA ; suitsa@missouri.eduDirect D-H exchange in radicals is investigated in a quasi-uniform flow employing chirped-pulse millimeter-wave spectroscopy. Inspired by the H-atom catalyzed isomerization of C _3 H _2 reported in our previous study, D-atom reactions with the propargyl (C _3 H _3 ) radical and its photoproducts were investigated. We observed very efficient D-atom enrichment in the photoproducts through an analogous process of D addition/H elimination to C _3 H _2 isomers occurring at 40 K or below. Cyclic C _3 HD is the only deuterated isomer observed, consistent with the expected addition/elimination yielding the lowest energy product. The other expected addition/elimination product, deuterated propargyl, is not directly detected, although its presence is inferred by the observations in the latter part of the flow. There, in the high-density region of the flow, we observed both isotopomers of singly deuterated propyne attributed to stabilization of the H+C _3 H _2 D or D+C _3 H _3 adducts. The implications of these observations for the deuterium fractionation of hydrocarbon radicals in astrochemical environments is discussed with the support of a monodeuterated chemical kinetic model.https://doi.org/10.3847/1538-4357/acac1dAstrochemistryChemical abundancesIsotopic abundances |
| spellingShingle | Nureshan Dias Ranil M. Gurusinghe Bernadette M. Broderick Tom J Millar Arthur G. Suits Direct D-atom Incorporation in Radicals: An Overlooked Pathway for Deuterium Fractionation The Astrophysical Journal Astrochemistry Chemical abundances Isotopic abundances |
| title | Direct D-atom Incorporation in Radicals: An Overlooked Pathway for Deuterium Fractionation |
| title_full | Direct D-atom Incorporation in Radicals: An Overlooked Pathway for Deuterium Fractionation |
| title_fullStr | Direct D-atom Incorporation in Radicals: An Overlooked Pathway for Deuterium Fractionation |
| title_full_unstemmed | Direct D-atom Incorporation in Radicals: An Overlooked Pathway for Deuterium Fractionation |
| title_short | Direct D-atom Incorporation in Radicals: An Overlooked Pathway for Deuterium Fractionation |
| title_sort | direct d atom incorporation in radicals an overlooked pathway for deuterium fractionation |
| topic | Astrochemistry Chemical abundances Isotopic abundances |
| url | https://doi.org/10.3847/1538-4357/acac1d |
| work_keys_str_mv | AT nureshandias directdatomincorporationinradicalsanoverlookedpathwayfordeuteriumfractionation AT ranilmgurusinghe directdatomincorporationinradicalsanoverlookedpathwayfordeuteriumfractionation AT bernadettembroderick directdatomincorporationinradicalsanoverlookedpathwayfordeuteriumfractionation AT tomjmillar directdatomincorporationinradicalsanoverlookedpathwayfordeuteriumfractionation AT arthurgsuits directdatomincorporationinradicalsanoverlookedpathwayfordeuteriumfractionation |