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Sola IR, García-Vela A. Absolute control over the quantum yield of a photodissociation reaction mediated by nonadiabatic couplings. Chem Sci 2024:d4sc03235g. [PMID: 39220160 PMCID: PMC11350398 DOI: 10.1039/d4sc03235g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2024] [Accepted: 08/19/2024] [Indexed: 09/04/2024] Open
Abstract
Control of molecular reaction dynamics with laser pulses has been developed in the last decades. Among the different magnitudes whose control has been actively pursued, the branching ratio between different product channels constitutes the clearest signature of quantum control. In polyatomic molecules, the dynamics in the excited state is quagmired by non-adiabatic couplings, which are not directly affected by the laser, making control over the branching ratio a very demanding challenge. Here we present a control scheme for the CH3I photodissociation in the A band, that modifies the quantum yield of the two fragmentation channels of the process. The scheme relies on the optimized preparation of an initial superposition of vibrational states in the ground potential, which further interfere upon the excitation with a broad pump pulse. This interference can suppress any of the channels, regardless of its dominance, and can be achieved over the whole spectral range of the A band. Furthermore, it can be accomplished without strong fields or direct intervention during the dynamics in the excited states: the whole control is predetermined from the outset. The present work thus opens the possibility of extensive and universal control of the channel branching ratio in complex photodissociation processes.
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Affiliation(s)
- Ignacio R Sola
- Departamento de Química Física, Universidad Complutense de Madrid (and Unidad Asociada I+D+I al CSIC) 28040 Madrid Spain
| | - Alberto García-Vela
- Instituto de Física Fundamental, Consejo Superior de Investigaciones Científicas Serrano 123 28006 Madrid Spain
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2
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Fang M, Zhao X, Liu Y, Shao Y, Chen N, Luo M, Zhang L, Liu Q, Ma L, Xu D, Hou X. Occurrence, evolution and degradation of heavy haze events in Beijing traced by iodine-127 and iodine-129 in aerosols. CHINESE CHEM LETT 2022. [DOI: 10.1016/j.cclet.2022.02.073] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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3
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Hafliðason A, Jiang MX, Kvaran Á. Photo- and autoionization processes of superexcited iodine atoms in MPI of CH3I and HI. Chem Phys 2021. [DOI: 10.1016/j.chemphys.2020.111016] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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Yang CH, Bhattacharyya S, Liu L, Fang WH, Liu K. Real-time tracking of the entangled pathways in the multichannel photodissociation of acetaldehyde. Chem Sci 2020; 11:6423-6430. [PMID: 34094106 PMCID: PMC8159351 DOI: 10.1039/d0sc00063a] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
The roaming mechanism, an unconventional reaction path, was discovered more than a decade ago in the studies of formaldehyde photodissociation, H2CO → H2 + CO. Since then, observations of roaming have been claimed in numerous photochemical processes. A closer examination of the presented data, however, revealed that evidence for roaming is not always unequivocal, and some of the conclusions could be misleading. We report here an in-depth, joint experimental and theoretical study of the title reaction. By tracking the time-evolution of the pair-correlated product state distributions, we decipher the competing, interwoven reaction pathways that lead to the radical (CH3 + HCO) and molecular (CH4 + CO) products. Possible roaming pathways are then elucidated and a more precise descriptor of the phenomenon is delineated.
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Affiliation(s)
- Chung-Hsin Yang
- Institute of Atomic and Molecular Sciences (IAMS), Academia Sinica P. O. Box 23-166 Taipei Taiwan 10617
| | - Surjendu Bhattacharyya
- Institute of Atomic and Molecular Sciences (IAMS), Academia Sinica P. O. Box 23-166 Taipei Taiwan 10617
| | - Lihong Liu
- Key Laboratory of Theoretical and Computational Photochemistry, Ministry of Education, Department of Chemistry, Beijing Normal University Beijing 100875 P. R. China
| | - Wei-Hai Fang
- Key Laboratory of Theoretical and Computational Photochemistry, Ministry of Education, Department of Chemistry, Beijing Normal University Beijing 100875 P. R. China
| | - Kopin Liu
- Institute of Atomic and Molecular Sciences (IAMS), Academia Sinica P. O. Box 23-166 Taipei Taiwan 10617 .,State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, CAS Dalian 116023 P. R. China.,Aerosol Science Research Center, National Sun Yat-sen University Kaohsiung Taiwan 80424
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Hafliðason A, Glodic P, Koumarianou G, Samartzis PC, Kvaran Á. Two-color studies of CH 3Br excitation dynamics with MPI and slice imaging. Phys Chem Chem Phys 2019; 21:10391-10401. [PMID: 31065628 DOI: 10.1039/c8cp06376a] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Two-color pump-probe experiments were performed to explore the multiphoton dynamics of CH3Br at high excitation energies of 8-10 eV, involving two-photon resonant excitations to a number of np and nd Rydberg states (pump) followed by REMPI detection (probe) of the Br, Br* and CH3(X) photoproducts. Slice images of Br+ and CH3+ ions were recorded in pump-only, probe-only and pump and probe experiments. Kinetic-energy release spectra (KERs), as well as spatial anisotropy parameters, were extracted from the images to identify the processes and the dynamics involved. Predissociation channels, following the two-photon resonant excitations and non-resonant photodissociation forming CH3(X) and Br/Br*, were identified and characterized. Furthermore, the probe excitations for CH3(X) involved near-resonant excitations to lower energy 5s Rydberg states of CH3Br. In three-photon excitation processes, a striking contrast is seen between excitations via the p/d and the s Rydberg states. Involvement of high-energy interactions between Rydberg and ion-pair states is identified.
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Affiliation(s)
- Arnar Hafliðason
- Science Institute, University of Iceland, Dunhagi 3, 107 Reykjavík, Iceland.
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Marggi Poullain S, Chicharro DV, Navarro E, Rubio-Lago L, González-Vázquez J, Bañares L. Photodissociation dynamics of bromoiodomethane from the first and second absorption bands. A combined velocity map and slice imaging study. Phys Chem Chem Phys 2018; 20:3490-3503. [PMID: 29335697 DOI: 10.1039/c7cp07077b] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Ion imaging is applied to disentangle the selective bond cleavage in the photodissociation of bromoiodomethane from the two first absorption bands.
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Affiliation(s)
- Sonia Marggi Poullain
- Departamento de Qumica Fsica I
- Facultad de Ciencias Qumicas
- Universidad Complutense de Madrid
- 28040 Madrid
- Spain
| | - David V. Chicharro
- Departamento de Qumica Fsica I
- Facultad de Ciencias Qumicas
- Universidad Complutense de Madrid
- 28040 Madrid
- Spain
| | - Eduardo Navarro
- Departamento de Qumica Fsica I
- Facultad de Ciencias Qumicas
- Universidad Complutense de Madrid
- 28040 Madrid
- Spain
| | - Luis Rubio-Lago
- Departamento de Qumica Fsica I
- Facultad de Ciencias Qumicas
- Universidad Complutense de Madrid
- 28040 Madrid
- Spain
| | - Jesús González-Vázquez
- Departamento de Qumica
- Módulo 13
- Facultad de Ciencias
- Universidad Autónoma de Madrid
- 28049 Madrid
| | - Luis Bañares
- Departamento de Qumica Fsica I
- Facultad de Ciencias Qumicas
- Universidad Complutense de Madrid
- 28040 Madrid
- Spain
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Vaida ME, Bernhardt TM. Surface-Aligned Femtochemistry: Molecular Reaction Dynamics on Oxide Surfaces. SPRINGER SERIES IN CHEMICAL PHYSICS 2014. [DOI: 10.1007/978-3-319-02051-8_10] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/04/2022]
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Hayakawa S, Tsujinaka T, Fujihara A. Dissociation mechanisms of excited CH3X (X = Cl, Br, and I) formed via high-energy electron transfer using alkali metal targets. J Chem Phys 2012; 137:184308. [PMID: 23163372 DOI: 10.1063/1.4765103] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
High-energy electron transfer dissociation (HE-ETD) on collisions with alkali metal targets (Cs, K, and Na) was investigated for CH(3)X(+) (X = Cl, Br, and I) ions by a charge inversion mass spectrometry. Relative peak intensities of the negative ions formed via HE-ETD strongly depend on the precursor ions and the target alkali metals. The dependency is explained by the exothermicities of the respective dissociation processes. Peak shapes of the negative ions, especially of the X(-) ions, which comprise a triangle and a trapezoid, also strongly depend on the precursor ions and the target alkali metals. The trapezoidal part of the I(-) peak observed with the Na target is more dominant and much broader than that with the Cs target. This dependence on the targets shows an inverse relation between the peak width and the available energy, which corresponds to the exothermicity assuming formation of fragment pair in their ground internal states. From a comparison of the kinetic energy release value calculated from the trapezoidal shape of I(-) with the available energy of the near-resonant level on the CH(3)I potential energy curve reported by ab initio calculations, the trapezoidal part is attributed to the dissociation to CH(3) + I((2)P(3/2)) via the repulsive (3)Q(1) state of CH(3)I, which is not dominant in the photo-dissociation of CH(3)I. The observation of trapezoid shape of the CH(2)I(-) peak with the Cs target indicates spontaneous dissociation via repulsive potential from the (3)R(2) Rydberg state, although the correlation between the (3)R(2) Rydberg state and relevant repulsive states has not been reported by any theoretical calculation.
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Affiliation(s)
- Shigeo Hayakawa
- Department of Chemistry, Graduate School of Science, Osaka Prefecture University, 1-1, Gakuencho, Nakaku, Sakai, Osaka 599-8531, Japan.
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Yu Z, Cheng M, Xu X, Yu D, Du Y, Zhu Q. Vibrational state distributions following the photodissociation of CF3I near 304nm. Chem Phys Lett 2010. [DOI: 10.1016/j.cplett.2010.02.044] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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10
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Vaida ME, Bernhardt TM. Surface-Aligned Femtochemistry: Real-Time Dynamics of Photoinduced I2Formation from CD3I on MgO(100). Chemphyschem 2010; 11:804-7. [DOI: 10.1002/cphc.200900920] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Hua L, Shen H, Hu C, Zhang B. Photoelectron imaging of atomic chlorine and bromine following photolysis of CH2BrCl. J Chem Phys 2008; 129:244308. [DOI: 10.1063/1.3047756] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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12
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Zhang XP, Lee WB, Lin KC. Nonadiabatic Transition in the A-Band Photodissociation of Ethyl Iodide from 294 to 308 nm by Using Velocity Imaging Detection. J Phys Chem A 2008; 113:35-9. [DOI: 10.1021/jp805118w] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Xiao-Peng Zhang
- Department of Chemistry, National Taiwan University, Taipei 106, and Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei 106, Taiwan
| | - Wei-Bin Lee
- Department of Chemistry, National Taiwan University, Taipei 106, and Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei 106, Taiwan
| | - King-Chuen Lin
- Department of Chemistry, National Taiwan University, Taipei 106, and Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei 106, Taiwan
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Hu C, Pei S, Chang C, Liu K. On the use of photoelectron spectroscopy to probe the dynamics of a dissociative intermediate state. Mol Phys 2008. [DOI: 10.1080/00268970701843758] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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