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Chen Z, Li Z, Xie J, Zhang P, Tong T, Wang Y, Hu J, Wörner HJ, Tian SX. Direct Observation of Anionic Yields from the Liquid-Vapor Interface by Electron Irradiation. J Phys Chem Lett 2024; 15:5607-5611. [PMID: 38758196 DOI: 10.1021/acs.jpclett.4c00521] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/18/2024]
Abstract
Dissociative electron attachment (DEA) is widely believed to play a high-profile role in ionizing radiation damages of bioorganic molecules, and its fundamentals are mainly learned from the gas-phase studies. However, the DEA process in aqueous solution is still in debate. Here we provide experimental evidence about the DEA processes of liquid methanol by using electron-impact-time-delayed mass spectrometry. In contrast to the gas- and solid-phase DEAs, methoxide ion CH3O- is the predominant product from the liquid interface. Furthermore, this anion can be produced with both the primary low-energy electrons and the inelastically scattered and secondary low-energy electrons. On the contrary, the primary low-energy electrons in the liquid bulk are more likely to be solvated, rather than directly participating in the DEA process. Our study provides new insights into radiation chemistry, particularly of bioorganic relevance.
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Affiliation(s)
- Ziwei Chen
- Department of Chemical Physics, University of Science and Technology of China, Hefei 230026, China
| | - Ziyuan Li
- Department of Chemical Physics, University of Science and Technology of China, Hefei 230026, China
| | - Jingchen Xie
- Department of Chemical Physics, University of Science and Technology of China, Hefei 230026, China
| | - Pengju Zhang
- Laboratory for Physical Chemistry, ETH Zürich, Vladimir-Prelog-Weg 2, 8093 Zürich, Switzerland
| | - Tiantian Tong
- Department of Chemical Physics, University of Science and Technology of China, Hefei 230026, China
| | - Yue Wang
- Department of Chemical Physics, University of Science and Technology of China, Hefei 230026, China
| | - Jie Hu
- Hefei National Research Center for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei 230026, China
| | - Hans Jakob Wörner
- Laboratory for Physical Chemistry, ETH Zürich, Vladimir-Prelog-Weg 2, 8093 Zürich, Switzerland
| | - Shan Xi Tian
- Department of Chemical Physics, University of Science and Technology of China, Hefei 230026, China
- Hefei National Research Center for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei 230026, China
- Hefei National Laboratory, University of Science and Technology of China, Hefei 230088, China
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2
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Nag P, Ranković M, Polášek M, Čurík R, Slaughter DS, Fedor J. Contrasting Dynamics in Isoelectronic Anions Formed by Electron Attachment. J Phys Chem Lett 2024; 15:895-902. [PMID: 38241169 PMCID: PMC10839900 DOI: 10.1021/acs.jpclett.3c03460] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2023] [Revised: 01/09/2024] [Accepted: 01/12/2024] [Indexed: 01/21/2024]
Abstract
Cyanogen NCCN and cyanoacetylene HCCCN are isoelectronic molecules, and as such, they have many similar properties. We focus on the bond cleavage in these induced by the dissociative electron attachment. In both molecules, resonant electron attachment produces CN- with very similar energy dependence. We investigate the very different dissociation dynamics, in each of the two molecules, revealed by velocity map imaging of this common fragment. Different dynamics are manifested both in the excess energy partitioning and in the angular distributions of fragments. Based on the comparison with electron energy loss spectra, which provide information about possible parent states of the resonances (both optically allowed and forbidden excited states of the neutral target), we ascribe the observed effect to the distortion of the nuclear frame during the formation of core-excited resonance in cyanoacetylene. The proposed mechanism also explains a puzzling difference in the magnitude of the CN- cross section in the two molecules which has been so far unexplained.
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Affiliation(s)
- P. Nag
- J.
Heyrovský Institute of Physical Chemistry, The Czech Academy of Sciences, Dolejškova 3, 18223 Prague, Czech
Republic
| | - M. Ranković
- J.
Heyrovský Institute of Physical Chemistry, The Czech Academy of Sciences, Dolejškova 3, 18223 Prague, Czech
Republic
| | - M. Polášek
- J.
Heyrovský Institute of Physical Chemistry, The Czech Academy of Sciences, Dolejškova 3, 18223 Prague, Czech
Republic
| | - R. Čurík
- J.
Heyrovský Institute of Physical Chemistry, The Czech Academy of Sciences, Dolejškova 3, 18223 Prague, Czech
Republic
| | - D. S. Slaughter
- Chemical
Sciences Division, Lawrence Berkeley National
Laboratory, Berkeley, California 94720, United States
| | - J. Fedor
- J.
Heyrovský Institute of Physical Chemistry, The Czech Academy of Sciences, Dolejškova 3, 18223 Prague, Czech
Republic
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3
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Xie J, Fan M, Tian SX. Dissociation Dynamics of Anionic Nitrogen Dioxide in the Low-Lying Resonant States. J Phys Chem Lett 2023; 14:598-603. [PMID: 36633551 DOI: 10.1021/acs.jpclett.2c03697] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
Experimental studies of the dynamics near the molecular dissociation threshold are frequently frustrated, due to the small cross sections and the demand for identification of close-lying electronic states or nuclear motions with multiple degrees of freedom. Using the high-resolution anion velocity map imaging technique, here we report a dynamics study of the dissociations of anionic nitrogen dioxide in low-lying resonant states formed by electron attachment [e- + NO2 (X2A1) → NO2- → NO (X2Π) + O- (2P)]. The long-term puzzling issues about the near-threshold dissociations of NO2- are settled. We suggest that three low-lying resonant states (1B1, 3B1, and 3B2) of NO2- contribute to the production of O- at attachment energies of <5 eV. Furthermore, B1 and B2 symmetries of the resonant states lead to different anisotropies of the O- angular distribution. At the relatively high electron attachment energies, a prompt fragmentation in the molecular bent conformation competes with an indirect dissociation in the straightened conformation.
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Affiliation(s)
- Jingchen Xie
- Department of Chemical Physics, Collaborative Innovation Center of Chemistry for Energy Materials (iChEM), University of Science and Technology of China, Hefei230026, China
| | - Mengyuan Fan
- Department of Chemical Physics, Collaborative Innovation Center of Chemistry for Energy Materials (iChEM), University of Science and Technology of China, Hefei230026, China
| | - Shan Xi Tian
- Department of Chemical Physics, Collaborative Innovation Center of Chemistry for Energy Materials (iChEM), University of Science and Technology of China, Hefei230026, China
- Hefei National Research Center for Physical Sciences at Microscale, University of Science and Technology of China, Hefei230026, China
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