Photodissociation transition states characterized by chirped pulse millimeter wave spectroscopy
© 2020 National Academy of Sciences. All rights reserved. The 193-nm photolysis of CH2CHCN illustrates the capability of chirped-pulse Fourier transform millimeter-wave spectroscopy to characterize transition states. We investigate the HCN, HNC photofragments in highly excited vibrational states usi...
| Main Authors: | , , , , , , , , |
|---|---|
| Andre forfattere: | |
| Format: | Article |
| Sprog: | English |
| Udgivet: |
Proceedings of the National Academy of Sciences
2021
|
| Online adgang: | https://hdl.handle.net/1721.1/136575 |
| _version_ | 1826194899543785472 |
|---|---|
| author | Prozument, Kirill Baraban, Joshua H Changala, P Bryan Park, G Barratt Shaver, Rachel G Muenter, John S Klippenstein, Stephen J Chernyak, Vladimir Y Field, Robert W |
| author2 | Massachusetts Institute of Technology. Department of Chemistry |
| author_facet | Massachusetts Institute of Technology. Department of Chemistry Prozument, Kirill Baraban, Joshua H Changala, P Bryan Park, G Barratt Shaver, Rachel G Muenter, John S Klippenstein, Stephen J Chernyak, Vladimir Y Field, Robert W |
| author_sort | Prozument, Kirill |
| collection | MIT |
| description | © 2020 National Academy of Sciences. All rights reserved. The 193-nm photolysis of CH2CHCN illustrates the capability of chirped-pulse Fourier transform millimeter-wave spectroscopy to characterize transition states. We investigate the HCN, HNC photofragments in highly excited vibrational states using both frequency and intensity information. Measured relative intensities of J = 1–0 rotational transition lines yield vibrational-level population distributions (VPD). These VPDs encode the properties of the parent molecule transition state at which the fragment molecule was born. A Poisson distribution formalism, based on the generalized Franck–Condon principle, is proposed as a framework for extracting information about the transition-state structure from the observed VPD. We employ the isotopologue CH2CDCN to disentangle the unimolecular 3-center DCN elimination mechanism from other pathways to HCN. Our experimental results reveal a previously unknown transition state that we tentatively associate with the HCN eliminated via a secondary, bimolecular reaction. |
| first_indexed | 2024-09-23T10:03:57Z |
| format | Article |
| id | mit-1721.1/136575 |
| institution | Massachusetts Institute of Technology |
| language | English |
| last_indexed | 2024-09-23T10:03:57Z |
| publishDate | 2021 |
| publisher | Proceedings of the National Academy of Sciences |
| record_format | dspace |
| spelling | mit-1721.1/1365752023-02-28T20:34:48Z Photodissociation transition states characterized by chirped pulse millimeter wave spectroscopy Prozument, Kirill Baraban, Joshua H Changala, P Bryan Park, G Barratt Shaver, Rachel G Muenter, John S Klippenstein, Stephen J Chernyak, Vladimir Y Field, Robert W Massachusetts Institute of Technology. Department of Chemistry © 2020 National Academy of Sciences. All rights reserved. The 193-nm photolysis of CH2CHCN illustrates the capability of chirped-pulse Fourier transform millimeter-wave spectroscopy to characterize transition states. We investigate the HCN, HNC photofragments in highly excited vibrational states using both frequency and intensity information. Measured relative intensities of J = 1–0 rotational transition lines yield vibrational-level population distributions (VPD). These VPDs encode the properties of the parent molecule transition state at which the fragment molecule was born. A Poisson distribution formalism, based on the generalized Franck–Condon principle, is proposed as a framework for extracting information about the transition-state structure from the observed VPD. We employ the isotopologue CH2CDCN to disentangle the unimolecular 3-center DCN elimination mechanism from other pathways to HCN. Our experimental results reveal a previously unknown transition state that we tentatively associate with the HCN eliminated via a secondary, bimolecular reaction. 2021-10-27T20:36:04Z 2021-10-27T20:36:04Z 2020 2020-09-22T16:14:46Z Article http://purl.org/eprint/type/JournalArticle https://hdl.handle.net/1721.1/136575 en 10.1073/PNAS.1911326116 Proceedings of the National Academy of Sciences of the United States of America Article is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use. application/pdf Proceedings of the National Academy of Sciences PNAS |
| spellingShingle | Prozument, Kirill Baraban, Joshua H Changala, P Bryan Park, G Barratt Shaver, Rachel G Muenter, John S Klippenstein, Stephen J Chernyak, Vladimir Y Field, Robert W Photodissociation transition states characterized by chirped pulse millimeter wave spectroscopy |
| title | Photodissociation transition states characterized by chirped pulse millimeter wave spectroscopy |
| title_full | Photodissociation transition states characterized by chirped pulse millimeter wave spectroscopy |
| title_fullStr | Photodissociation transition states characterized by chirped pulse millimeter wave spectroscopy |
| title_full_unstemmed | Photodissociation transition states characterized by chirped pulse millimeter wave spectroscopy |
| title_short | Photodissociation transition states characterized by chirped pulse millimeter wave spectroscopy |
| title_sort | photodissociation transition states characterized by chirped pulse millimeter wave spectroscopy |
| url | https://hdl.handle.net/1721.1/136575 |
| work_keys_str_mv | AT prozumentkirill photodissociationtransitionstatescharacterizedbychirpedpulsemillimeterwavespectroscopy AT barabanjoshuah photodissociationtransitionstatescharacterizedbychirpedpulsemillimeterwavespectroscopy AT changalapbryan photodissociationtransitionstatescharacterizedbychirpedpulsemillimeterwavespectroscopy AT parkgbarratt photodissociationtransitionstatescharacterizedbychirpedpulsemillimeterwavespectroscopy AT shaverrachelg photodissociationtransitionstatescharacterizedbychirpedpulsemillimeterwavespectroscopy AT muenterjohns photodissociationtransitionstatescharacterizedbychirpedpulsemillimeterwavespectroscopy AT klippensteinstephenj photodissociationtransitionstatescharacterizedbychirpedpulsemillimeterwavespectroscopy AT chernyakvladimiry photodissociationtransitionstatescharacterizedbychirpedpulsemillimeterwavespectroscopy AT fieldrobertw photodissociationtransitionstatescharacterizedbychirpedpulsemillimeterwavespectroscopy |