Probing cis-trans isomerization in the S1 state of C2H2 via H-atom action and hot band-pumped IR-UV double resonance spectroscopies
We report novel experimental strategies that should prove instrumental in extending the vibrational and rotational assignments of the S1 state of acetylene, C[subscript 2]H[subscript 2], in the region of the cis-trans isomerization barrier. At present, the assignments are essentially complete up to...
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| Format: | Article |
| Language: | en_US |
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American Institute of Physics (AIP)
2017
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| Online Access: | http://hdl.handle.net/1721.1/106799 https://orcid.org/0000-0002-7609-4205 |
| _version_ | 1826207764329791488 |
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| author | Changala, P. Bryan Baraban, Joshua H. Merer, Anthony J. Field, Robert W. Baraban, Joshua Herschel Field, Robert W |
| author2 | Massachusetts Institute of Technology. Department of Chemistry |
| author_facet | Massachusetts Institute of Technology. Department of Chemistry Changala, P. Bryan Baraban, Joshua H. Merer, Anthony J. Field, Robert W. Baraban, Joshua Herschel Field, Robert W |
| author_sort | Changala, P. Bryan |
| collection | MIT |
| description | We report novel experimental strategies that should prove instrumental in extending the vibrational and rotational assignments of the S1 state of acetylene, C[subscript 2]H[subscript 2], in the region of the cis-trans isomerization barrier. At present, the assignments are essentially complete up to ∼500 cm[superscript −1] below the barrier. Two difficulties arise when the assignments are continued to higher energies. One is that predissociation into C[subscript 2]H + H sets in roughly 1100 cm[superscript −1] below the barrier; the resulting quenching of laser-induced fluorescence (LIF) reduces its value for recording spectra in this region. The other difficulty is that tunneling through the barrier causes a staggering in the K-rotational structure of isomerizing vibrational levels. The assignment of these levels requires data for K values up to at least 3. Given the rotational selection rule K' − ℓ" = ± 1, such data must be obtained via excited vibrational levels of the ground state with ℓ" > 0. In this paper, high resolution H-atom resonance-enhanced multiphoton ionization spectra are demonstrated to contain predissociated bands which are almost invisible in LIF spectra, while preliminary data using a hyperthermal pulsed nozzle show that ℓ" = 2 states can be selectively populated in a jet, giving access to K' = 3 states in IR-UV double resonance. |
| first_indexed | 2024-09-23T13:54:35Z |
| format | Article |
| id | mit-1721.1/106799 |
| institution | Massachusetts Institute of Technology |
| language | en_US |
| last_indexed | 2024-09-23T13:54:35Z |
| publishDate | 2017 |
| publisher | American Institute of Physics (AIP) |
| record_format | dspace |
| spelling | mit-1721.1/1067992022-10-01T17:57:06Z Probing cis-trans isomerization in the S1 state of C2H2 via H-atom action and hot band-pumped IR-UV double resonance spectroscopies Changala, P. Bryan Baraban, Joshua H. Merer, Anthony J. Field, Robert W. Baraban, Joshua Herschel Field, Robert W Massachusetts Institute of Technology. Department of Chemistry Field, Robert W Changala, P. Bryan Baraban, Joshua Herschel Field, Robert W We report novel experimental strategies that should prove instrumental in extending the vibrational and rotational assignments of the S1 state of acetylene, C[subscript 2]H[subscript 2], in the region of the cis-trans isomerization barrier. At present, the assignments are essentially complete up to ∼500 cm[superscript −1] below the barrier. Two difficulties arise when the assignments are continued to higher energies. One is that predissociation into C[subscript 2]H + H sets in roughly 1100 cm[superscript −1] below the barrier; the resulting quenching of laser-induced fluorescence (LIF) reduces its value for recording spectra in this region. The other difficulty is that tunneling through the barrier causes a staggering in the K-rotational structure of isomerizing vibrational levels. The assignment of these levels requires data for K values up to at least 3. Given the rotational selection rule K' − ℓ" = ± 1, such data must be obtained via excited vibrational levels of the ground state with ℓ" > 0. In this paper, high resolution H-atom resonance-enhanced multiphoton ionization spectra are demonstrated to contain predissociated bands which are almost invisible in LIF spectra, while preliminary data using a hyperthermal pulsed nozzle show that ℓ" = 2 states can be selectively populated in a jet, giving access to K' = 3 states in IR-UV double resonance. United States. Department of Energy (Grant No. DE-FG0287ER13671) Chinese Academy of Sciences (Distinguished Visiting Professorship) Natural Sciences and Engineering Research Council of Canada (NSERC) 2017-01-31T15:11:31Z 2017-01-31T15:11:31Z 2015-08 2015-07 Article http://purl.org/eprint/type/JournalArticle 0021-9606 1089-7690 http://hdl.handle.net/1721.1/106799 Changala, P. Bryan, Joshua H. Baraban, Anthony J. Merer, and Robert W. Field. “Probing Cis-Trans Isomerization in the S1 State of C2H2 via H-Atom Action and Hot Band-Pumped IR-UV Double Resonance Spectroscopies.” J. Chem. Phys. 143, no. 8 (August 28, 2015): 084310. © 2015 AIP Publishing LLC. https://orcid.org/0000-0002-7609-4205 en_US http://dx.doi.org/10.1063/1.4929588 Journal of Chemical Physics 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 Institute of Physics (AIP) Prof. Field via Erja Kajosalo |
| spellingShingle | Changala, P. Bryan Baraban, Joshua H. Merer, Anthony J. Field, Robert W. Baraban, Joshua Herschel Field, Robert W Probing cis-trans isomerization in the S1 state of C2H2 via H-atom action and hot band-pumped IR-UV double resonance spectroscopies |
| title | Probing cis-trans isomerization in the S1 state of C2H2 via H-atom action and hot band-pumped IR-UV double resonance spectroscopies |
| title_full | Probing cis-trans isomerization in the S1 state of C2H2 via H-atom action and hot band-pumped IR-UV double resonance spectroscopies |
| title_fullStr | Probing cis-trans isomerization in the S1 state of C2H2 via H-atom action and hot band-pumped IR-UV double resonance spectroscopies |
| title_full_unstemmed | Probing cis-trans isomerization in the S1 state of C2H2 via H-atom action and hot band-pumped IR-UV double resonance spectroscopies |
| title_short | Probing cis-trans isomerization in the S1 state of C2H2 via H-atom action and hot band-pumped IR-UV double resonance spectroscopies |
| title_sort | probing cis trans isomerization in the s1 state of c2h2 via h atom action and hot band pumped ir uv double resonance spectroscopies |
| url | http://hdl.handle.net/1721.1/106799 https://orcid.org/0000-0002-7609-4205 |
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