Proton Transfer in Concentrated Aqueous Hydroxide Visualized using Ultrafast Infrared Spectroscopy
While it is generally recognized that the hydroxide ion can rapidly diffuse through aqueous solution due to its ability to accept a proton from a neighboring water molecule, a description of the OH− solvation structure and mechanism of proton transfer to the ion remains controversial. In this report...
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| Format: | Article |
| Language: | en_US |
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American Chemical Society
2012
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| Online Access: | http://hdl.handle.net/1721.1/69657 |
| _version_ | 1826188178350931968 |
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| author | Roberts, Sean Thomas Ramasesha, Krupa Petersen, Poul B. Mandal, Aritra Tokmakoff, Andrei |
| author2 | Massachusetts Institute of Technology. Department of Chemistry |
| author_facet | Massachusetts Institute of Technology. Department of Chemistry Roberts, Sean Thomas Ramasesha, Krupa Petersen, Poul B. Mandal, Aritra Tokmakoff, Andrei |
| author_sort | Roberts, Sean Thomas |
| collection | MIT |
| description | While it is generally recognized that the hydroxide ion can rapidly diffuse through aqueous solution due to its ability to accept a proton from a neighboring water molecule, a description of the OH− solvation structure and mechanism of proton transfer to the ion remains controversial. In this report, we present the results of femtosecond infrared spectroscopy measurements of the O−H stretching transition of dilute HOD dissolved in NaOD/D2O. Pump−probe, photon echo peak shift, and two-dimensional infrared spectroscopy experiments performed as a function of deuteroxide concentration are used to assign spectral signatures that arise from the OH− ion and its solvation shell. A spectral feature that decays on a 110 fs time scale is assigned to the relaxation of transiently formed configurations wherein a proton is equally shared between a HOD molecule and an OD− ion. Over picosecond waiting times, features appear in 2D IR spectra that are indicative of the exchange of population between OH− ions and HOD molecules due to deuteron transfer. The construction of a spectral model that includes spectral relaxation, chemical exchange, and thermalization processes, and self-consistently treats all of our data, allows us to qualitatively explain the results of our experiments and gives a lower bound of 3 ps for the deuteron transfer kinetics. |
| first_indexed | 2024-09-23T07:55:44Z |
| format | Article |
| id | mit-1721.1/69657 |
| institution | Massachusetts Institute of Technology |
| language | en_US |
| last_indexed | 2024-09-23T07:55:44Z |
| publishDate | 2012 |
| publisher | American Chemical Society |
| record_format | dspace |
| spelling | mit-1721.1/696572022-09-30T01:02:33Z Proton Transfer in Concentrated Aqueous Hydroxide Visualized using Ultrafast Infrared Spectroscopy Roberts, Sean Thomas Ramasesha, Krupa Petersen, Poul B. Mandal, Aritra Tokmakoff, Andrei Massachusetts Institute of Technology. Department of Chemistry Tokmakoff, Andrei Tokmakoff, Andrei Roberts, Sean Thomas Ramasesha, Krupa Petersen, Poul B. Mandal, Aritra While it is generally recognized that the hydroxide ion can rapidly diffuse through aqueous solution due to its ability to accept a proton from a neighboring water molecule, a description of the OH− solvation structure and mechanism of proton transfer to the ion remains controversial. In this report, we present the results of femtosecond infrared spectroscopy measurements of the O−H stretching transition of dilute HOD dissolved in NaOD/D2O. Pump−probe, photon echo peak shift, and two-dimensional infrared spectroscopy experiments performed as a function of deuteroxide concentration are used to assign spectral signatures that arise from the OH− ion and its solvation shell. A spectral feature that decays on a 110 fs time scale is assigned to the relaxation of transiently formed configurations wherein a proton is equally shared between a HOD molecule and an OD− ion. Over picosecond waiting times, features appear in 2D IR spectra that are indicative of the exchange of population between OH− ions and HOD molecules due to deuteron transfer. The construction of a spectral model that includes spectral relaxation, chemical exchange, and thermalization processes, and self-consistently treats all of our data, allows us to qualitatively explain the results of our experiments and gives a lower bound of 3 ps for the deuteron transfer kinetics. United States. Dept. of Energy (Contract No. DE-FG02-99ER14988) American Chemical Society (Petroleum Research Fund) Henry & Camille Dreyfus Foundation Carlsberg Foundation 2012-03-14T20:28:04Z 2012-03-14T20:28:04Z 2011-02 2011-01 Article http://purl.org/eprint/type/JournalArticle 1089-5639 1520-5215 http://hdl.handle.net/1721.1/69657 Roberts, Sean T. et al. “Proton Transfer in Concentrated Aqueous Hydroxide Visualized Using Ultrafast Infrared Spectroscopy.” The Journal of Physical Chemistry A 115.16 (2011): 3957–3972. en_US http://dx.doi.org/10.1021/jp108474p Journal of Physical Chemistry A 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 American Chemical Society Prof. Tokmakoff via Erja Kajosalo |
| spellingShingle | Roberts, Sean Thomas Ramasesha, Krupa Petersen, Poul B. Mandal, Aritra Tokmakoff, Andrei Proton Transfer in Concentrated Aqueous Hydroxide Visualized using Ultrafast Infrared Spectroscopy |
| title | Proton Transfer in Concentrated Aqueous Hydroxide Visualized using Ultrafast Infrared Spectroscopy |
| title_full | Proton Transfer in Concentrated Aqueous Hydroxide Visualized using Ultrafast Infrared Spectroscopy |
| title_fullStr | Proton Transfer in Concentrated Aqueous Hydroxide Visualized using Ultrafast Infrared Spectroscopy |
| title_full_unstemmed | Proton Transfer in Concentrated Aqueous Hydroxide Visualized using Ultrafast Infrared Spectroscopy |
| title_short | Proton Transfer in Concentrated Aqueous Hydroxide Visualized using Ultrafast Infrared Spectroscopy |
| title_sort | proton transfer in concentrated aqueous hydroxide visualized using ultrafast infrared spectroscopy |
| url | http://hdl.handle.net/1721.1/69657 |
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