Spectroscopic characterization of isomerization transition states
Transition state theory is central to our understanding of chemical reaction dynamics. We demonstrate a method for extracting transition state energies and properties from a characteristic pattern found in frequency-domain spectra of isomerizing systems. This pattern—a dip in the spacings of certain...
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| Format: | Article |
| Language: | en_US |
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American Association for the Advancement of Science (AAAS)
2017
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| Online Access: | http://hdl.handle.net/1721.1/107170 https://orcid.org/0000-0002-7609-4205 |
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| author | Mellau, Georg Ch. Stanton, John F. Merer, Anthony J. Baraban, Joshua Herschel Changala, P. Bryan Field, Robert W |
| author2 | Massachusetts Institute of Technology. Department of Chemistry |
| author_facet | Massachusetts Institute of Technology. Department of Chemistry Mellau, Georg Ch. Stanton, John F. Merer, Anthony J. Baraban, Joshua Herschel Changala, P. Bryan Field, Robert W |
| author_sort | Mellau, Georg Ch. |
| collection | MIT |
| description | Transition state theory is central to our understanding of chemical reaction dynamics. We demonstrate a method for extracting transition state energies and properties from a characteristic pattern found in frequency-domain spectra of isomerizing systems. This pattern—a dip in the spacings of certain barrier-proximal vibrational levels—can be understood using the concept of effective frequency, ω[superscript]eff. The method is applied to the cis-trans conformational change in the S[subscript 1] state of C[subscript 2]H[Subscript 2] and the bond-breaking HCN-HNC isomerization. In both cases, the barrier heights derived from spectroscopic data agree extremely well with previous ab initio calculations. We also show that it is possible to distinguish between vibrational modes that are actively involved in the isomerization process and those that are passive bystanders. |
| first_indexed | 2024-09-23T12:05:44Z |
| format | Article |
| id | mit-1721.1/107170 |
| institution | Massachusetts Institute of Technology |
| language | en_US |
| last_indexed | 2024-09-23T12:05:44Z |
| publishDate | 2017 |
| publisher | American Association for the Advancement of Science (AAAS) |
| record_format | dspace |
| spelling | mit-1721.1/1071702022-09-28T00:05:06Z Spectroscopic characterization of isomerization transition states Mellau, Georg Ch. Stanton, John F. Merer, Anthony J. Baraban, Joshua Herschel Changala, P. Bryan Field, Robert W Massachusetts Institute of Technology. Department of Chemistry Field, Robert W Baraban, Joshua Herschel Changala, P. Bryan Field, Robert W Transition state theory is central to our understanding of chemical reaction dynamics. We demonstrate a method for extracting transition state energies and properties from a characteristic pattern found in frequency-domain spectra of isomerizing systems. This pattern—a dip in the spacings of certain barrier-proximal vibrational levels—can be understood using the concept of effective frequency, ω[superscript]eff. The method is applied to the cis-trans conformational change in the S[subscript 1] state of C[subscript 2]H[Subscript 2] and the bond-breaking HCN-HNC isomerization. In both cases, the barrier heights derived from spectroscopic data agree extremely well with previous ab initio calculations. We also show that it is possible to distinguish between vibrational modes that are actively involved in the isomerization process and those that are passive bystanders. National Science Foundation (U.S.) (NSF Graduate Research Fellowship DGE 1144083) Alexander von Humboldt-Stiftung (Feodor Lynen fellowship) United States. Department of Energy (Grant DE-FG0287ER136) 2017-03-02T21:43:26Z 2017-03-02T21:43:26Z 2015-12 Article http://purl.org/eprint/type/JournalArticle 0036-8075 1095-9203 http://hdl.handle.net/1721.1/107170 Baraban, Joshua H., P. Bryan Changala, Georg Ch. Mellau, John F. Stanton, Anthony J. Merer and Robert W. Field. “Spectroscopic Characterization of Isomerization Transition States.” Science 350, no. 6266 (December 10, 2015): 1338–1342. https://orcid.org/0000-0002-7609-4205 en_US http://dx.doi.org/10.1126/science.aac9668 Science Creative Commons Attribution-Noncommercial-Share Alike http://creativecommons.org/licenses/by-nc-sa/4.0/ application/pdf American Association for the Advancement of Science (AAAS) Prof. Field via Erja Kajosalo |
| spellingShingle | Mellau, Georg Ch. Stanton, John F. Merer, Anthony J. Baraban, Joshua Herschel Changala, P. Bryan Field, Robert W Spectroscopic characterization of isomerization transition states |
| title | Spectroscopic characterization of isomerization transition states |
| title_full | Spectroscopic characterization of isomerization transition states |
| title_fullStr | Spectroscopic characterization of isomerization transition states |
| title_full_unstemmed | Spectroscopic characterization of isomerization transition states |
| title_short | Spectroscopic characterization of isomerization transition states |
| title_sort | spectroscopic characterization of isomerization transition states |
| url | http://hdl.handle.net/1721.1/107170 https://orcid.org/0000-0002-7609-4205 |
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