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Gao XF, An F, Li H, Xie JC, Wang XD, Meng X, Wu B, Xie DQ, Tian SX. Probing the Potential Energy Surfaces of BrCN - by Dissociative Electron Attachment. J Phys Chem Lett 2020; 11:9110-9116. [PMID: 33049137 DOI: 10.1021/acs.jpclett.0c02991] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
State coupling certainly determines the topologic features of the molecular potential energy surface (PES) and potentially diversifies chemical reaction pathways. Here we report the new PESs of BrCN- in the low-lying electronic states that are distinctly different from the previous predictions in the short Br-CN bond region but validated by the high-resolution ion velocity imaging measurements of low-energy dissociative electron attachment (DEA) to BrCN. Besides the vibrating CN- ions produced in the fast Br-CN bond stretching motions, we confirm that the ro-vibrating CN- ions with a nearly isotropic angular distribution are produced by receiving a torque in the combinational motion of Br-CN bond bending and stretching. The latter process is closely related to the potential well of BrCN- at the first excited state A2Π3/2 that arises from the Π-Σ state couplings. Our findings not only suggest that the PESs of other anionic cyanogen halides are in dire need of reexamination but also show that ion velocity imaging of the DEA process is a powerful experimental method for evaluating the theoretical PESs of molecular anions.
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Affiliation(s)
- Xiao-Fei Gao
- Hefei National Laboratory for Physical Sciences at the Microscale, Department of Chemical Physics, University of Science and Technology of China, Hefei 230026, China
| | - Feng An
- Key Laboratory of Mesoscopic Chemistry, School of Chemistry and Chemical Engineering, Institute of Theoretical and Computational Chemistry, Nanjing University, Nanjing 210023, China
| | - Hao Li
- Hefei National Laboratory for Physical Sciences at the Microscale, Department of Chemical Physics, University of Science and Technology of China, Hefei 230026, China
| | - Jing-Chen Xie
- Hefei National Laboratory for Physical Sciences at the Microscale, Department of Chemical Physics, University of Science and Technology of China, Hefei 230026, China
| | - Xu-Dong Wang
- Hefei National Laboratory for Physical Sciences at the Microscale, Department of Chemical Physics, University of Science and Technology of China, Hefei 230026, China
| | - Xin Meng
- Hefei National Laboratory for Physical Sciences at the Microscale, Department of Chemical Physics, University of Science and Technology of China, Hefei 230026, China
| | - Bin Wu
- Hefei National Laboratory for Physical Sciences at the Microscale, Department of Chemical Physics, University of Science and Technology of China, Hefei 230026, China
| | - Dai-Qian Xie
- Key Laboratory of Mesoscopic Chemistry, School of Chemistry and Chemical Engineering, Institute of Theoretical and Computational Chemistry, Nanjing University, Nanjing 210023, China
- Collaborative Innovation Center of Chemistry for Energy Materials (iChEM), University of Science and Technology of China, Hefei 230026, China
| | - Shan Xi Tian
- Hefei National Laboratory for Physical Sciences at the Microscale, Department of Chemical Physics, University of Science and Technology of China, Hefei 230026, China
- Collaborative Innovation Center of Chemistry for Energy Materials (iChEM), University of Science and Technology of China, Hefei 230026, China
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Khiri D, Chambaud G. Reaction of CN(-) with F, Cl, O, and S Atoms: Attachment or Associative Detachment? J Phys Chem A 2015; 119:11461-70. [PMID: 26517187 DOI: 10.1021/acs.jpca.5b08867] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Highly correlated ab initio wave functions within the UCCSD(T)-F12 approach have been used to map the potential energy surfaces (PESs) describing the reactivity of the CN(-) (X(1)Σ(+)) anion with neutral atoms present in interstellar media (F, Cl, O, and S). With the H atom, for comparison, the reaction [CN(-)((1)Σ(+)) + H((2)S)] evolves along the PES of the X(2)Σ(+) electronic ground state of HCN(-) (or HNC(-)) until the crossing with the X(1)Σ(+) electronic ground state of HCN (or HNC), where electron detachment occurs. The process is rather similar to the two halogen atoms F and Cl, with some differences due to the larger electron affinity of the halogens, making possible the existence of ClCN(-) in a (2)Σ(+) state. The reaction of CN(-) with O and S atoms proceeds via a multistep mechanism. The lowest electronic state at long distance, the (3)Π state arising from the [CN(-)((1)Σ(+)) + O/S((3)P)] reaction channel, does not correlate with the X(1)Σ(+) ground state of the XCN(-) anion (X = O or S). This (3)Π state and its bent components cross at medium RXC (RXN) distances the X(1)Σ(+) ground state of XCN(-) or XNC(-), and at shorter distances the X(2)Π state of the neutral XCN or XNC where the extra electron can detach. With both O and S atoms, it is shown that the spin-orbit couplings can efficiently lead the [CN(-)((1)Σ(+)) + O/S((3)P)] reaction toward the stable X(1)Σ(+) ground state of XCN(-) and XNC(-).
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Affiliation(s)
- D Khiri
- Université de Tunis El Manar , Laboratoire de Spectroscopie Atomique Moléculaire et Applications LSAMA, Tunis, Tunisia.,Université Paris-Est Marne-la-Vallée , Laboratoire MSME, UMR-8208 CNRS, Cité Descartes, Champs-sur-Marne, 77454 Marne-la-Vallée, France
| | - G Chambaud
- Université Paris-Est Marne-la-Vallée , Laboratoire MSME, UMR-8208 CNRS, Cité Descartes, Champs-sur-Marne, 77454 Marne-la-Vallée, France
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Weber JM. The interaction of negative charge with carbon dioxide – insight into solvation, speciation and reductive activation from cluster studies. INT REV PHYS CHEM 2014. [DOI: 10.1080/0144235x.2014.969554] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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Opoku-Agyeman B, Case AS, Lehman JH, Lineberger WC, McCoy AB. Nonadiabatic photofragmentation dynamics of BrCN-. J Chem Phys 2014; 141:084305. [PMID: 25173012 DOI: 10.1063/1.4892981] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
The photofragmentation dynamics of BrCN(-) in the 270-355 nm and the 430-600 nm wavelength regions is explored both experimentally and theoretically. In the case of excitation between 430 nm and 600 nm, it is found that the molecular ion accesses two dissociation channels with a measured 60:40 branching ratio that is nearly constant over this range of photon energies. The dominant product channel corresponds to Br(-) + CN, while the second channel correlates to spin-orbit excited Br(*) with CN(-). A larger wavelength dependence of the branching ratio is observed at shorter wavelengths, where the fraction of Br(-) based products ranges from 80% to 95% at 355 nm and 270 nm, respectively. These branching ratios are reproduced and the mechanisms are explored by quantum dynamics calculations based on ground and excited state potential energy surfaces for BrCN(-), evaluated at the SO-MRCISD level of theory. It is found that the electronic states that correlate to the two observed product channels are coupled through the spin-orbit terms in the electronic Hamiltonian. The strength of this coupling displays a strong dependence on the Br-CN angle. Specifically, after promotion to the excited state that is energetically accessible with 430-600 nm photons, it is found that when the wave packet accesses Br-CN separations of between 4 Å and 6 Å, predominantly the Br(-) + CN products are formed when the Br-CN angle is smaller than 120°. For larger values of the Br-CN angle, the Br(*) + CN(-) channel dominates. At the shorter wavelength excitation, the dynamics is complicated by a pair of states that correlate to electronically excited CN(*) + Br(-) products that borrow oscillator strength from the bright state, leading to an increase in the amount of Br(-) relative to CN(-). The implications of these findings are discussed and compared to the experimentally measured product branching ratios for the photodissociation of BrCN(-).
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Affiliation(s)
- Bernice Opoku-Agyeman
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, Ohio 43210, USA
| | - Amanda S Case
- JILA and Department of Chemistry and Biochemistry, University of Colorado, Boulder, Colorado 80309, USA
| | - Julia H Lehman
- JILA and Department of Chemistry and Biochemistry, University of Colorado, Boulder, Colorado 80309, USA
| | - W Carl Lineberger
- JILA and Department of Chemistry and Biochemistry, University of Colorado, Boulder, Colorado 80309, USA
| | - Anne B McCoy
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, Ohio 43210, USA
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Martin JP, Case AS, Gu Q, Darr JP, McCoy AB, Lineberger WC. Photofragmentation dynamics of ICN−(CO2)n clusters following visible excitation. J Chem Phys 2013; 139:064315. [DOI: 10.1063/1.4817664] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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