1
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Yuan Y, Tsai P. Photodissociation dynamics of acetaldehyde at 267 nm: A computational study of the
CO
‐forming channels. J CHIN CHEM SOC-TAIP 2023. [DOI: 10.1002/jccs.202300036] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/03/2023]
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2
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Tsai PY, Palazzetti F. Photodissociation dynamics of CO-forming channel of methyl formate at 193 nm: a computational study. Mol Phys 2021. [DOI: 10.1080/00268976.2021.1977405] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Affiliation(s)
- Po-Yu Tsai
- Department of Chemistry, National Chung Hsing University, Taichung, Taiwan
| | - Federico Palazzetti
- Department of Chemistry, Biology and Biotechnology, University of Perugia, Perugia, Italy
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3
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Lin K, Tso C, Kasai T. Beyond the rule of transition state: Identification of roaming routes in some cases of carbonyl compounds. J CHIN CHEM SOC-TAIP 2021. [DOI: 10.1002/jccs.202100039] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- King‐Chuen Lin
- Department of Chemistry National Taiwan University Taipei Taiwan
- Institute of Atomic and Molecular Sciences Academia Sinica Taipei Taiwan
| | - Cheng‐Jui Tso
- Department of Chemistry National Taiwan University Taipei Taiwan
| | - Toshio Kasai
- Department of Chemistry National Taiwan University Taipei Taiwan
- Institute of Scientific and Industrial Research Osaka University Osaka Japan
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4
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Palazzetti F, Tsai PY. Photodissociation Dynamics of CO-Forming Channels on the Ground-State Surface of Methyl Formate at 248 nm: Direct Dynamics Study and Assessment of Generalized Multicenter Impulsive Models. J Phys Chem A 2021; 125:1198-1220. [PMID: 33507759 DOI: 10.1021/acs.jpca.0c10464] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
The photodissociation dynamics of methyl formate in the electronic ground state S0, initiated by a 248 nm-wavelength laser, is studied by direct dynamics simulations. We analyze five channels, where four of them have as products CH3OH + CO, one leading to the formation of three fragments, H2CO + H2 + CO, and a channel characterized by a roaming transition state. The analysis of energy distribution among the degrees of freedom of the product and the comparison with experimental results previously published by other groups provide the ingredients to distinguish the examined dissociation pathways. The interpretation of the results proves that the characterization of dissociation mechanisms must rely on a dynamics approach involving multiple electronic states, including considerations on the features of the S1/S0 conical intersection. Here, we also assess the generalized multicenter impulsive model, GMCIM, that has been designed for dissociation processes with exit barriers, and the energy distribution in the products is predicted on the basis of information from the saddle points and the intrinsic reaction coordinates. Main features, advantages, limits, and future perspectives of the method are reported and discussed.
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Affiliation(s)
- Federico Palazzetti
- Dipartimento di Chimica, Biologia e Biotecnologie, Università degli Studi di Perugia, Perugia 06123, Italy
| | - Po-Yu Tsai
- Department of Chemistry, National Chung Hsing University, Taichung 402, Taiwan
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5
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Lin KC, Muthiah B, Chang HP, Kasai T, Chang YP. Halogen-related photodissociation in atmosphere: characterisation of atomic halogen, molecular halogen, and hydrogen halide. INT REV PHYS CHEM 2020. [DOI: 10.1080/0144235x.2020.1822590] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Affiliation(s)
- King-Chuen Lin
- Department of Chemistry, National Taiwan University, Taipei, Taiwan
- Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei, Taiwan
| | | | - Hsiu-Pu Chang
- Department of Chemistry, National Taiwan University, Taipei, Taiwan
| | - Toshio Kasai
- Department of Chemistry, National Taiwan University, Taipei, Taiwan
- Institute of Scientific and Industrial Research, Osaka University, Osaka, Japan
| | - Yuan-Pin Chang
- Department of Chemistry, National Sun Yat-sen University, Kaohsiung, Taiwan
- Aerosol Science Research Center, National Sun Yat-sen University, Kaohsiung, Taiwan
- Department of Medicinal and Applied Chemistry, Kaohsiung Medical University, Kaohsiung, Taiwan
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6
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Che DC, Nakamura M, Chang HP, Lin KC, Kasai T, Aquilanti V, Palazzetti F. UV Photodissociation of Halothane in a Focused Molecular Beam: Space-Speed Slice Imaging of Competitive Bond Breaking into Spin-Orbit-Selected Chlorine and Bromine Atoms. J Phys Chem A 2020; 124:5288-5296. [PMID: 32498517 DOI: 10.1021/acs.jpca.0c02800] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A molecular beam of halothane (2-bromo-2-chloro-1,1,1-trifluoroethane) is focused by a hexapolar electrostatic field and photolyzed by UV laser radiation at 234 nm. Angular and speed distributions of chlorine and bromine photofragments emitted from halothane are measured for both spin-orbit states independently. Although the dissociation energy of the C-Cl bond is larger than that of C-Br, the relative yield of Cl to Br was found to be approximately 2. Measured speed and angular distributions of atomic fragments show distinct kinetic energy release and scattering characteristics: for bromine, observed fast and aligned fragments exhibit a signature of a direct mode of dissociation for the C-Br bond, via the electronically excited potential energy surface denoted nσ*(C-Br), of repulsive nature; for chlorine, a variation in the features is observed for the dissociation pathway through nσ*(C-Cl), from a modality similar to the bromine case, leading to fragments with appreciable kinetic energy release and pronounced directionality, to a modality involving slow products, nearly isotopically distributed. The origin of this behavior can be attributed to nonadiabatic interaction operating between the nσ*(C-Br) and nσ*(C-Cl) surfaces. These results are not only relevant for a detailed understanding of adiabatic versus diabatic coupling mechanisms in the manifold of excited states populated by photon absorption, but they also point out the possibility of selectively inducing specific dissociation pathways, even when involving energetically unfavorable outcomes, such as, in this case, the prevailing rupture of the stronger C-Cl bond against that of the weaker C-Br bond.
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Affiliation(s)
- Dock-Chil Che
- Department of Chemistry, Graduate School of Science, Osaka University, Toyonaka, Osaka 560-0043, Japan
| | - Masaaki Nakamura
- Department of Chemistry, National Taiwan University, Taipei 10617, Taiwan
| | - Hsiu-Pu Chang
- Department of Chemistry, National Taiwan University, Taipei 10617, Taiwan
| | - King-Chuen Lin
- Department of Chemistry, National Taiwan University, Taipei 10617, Taiwan.,Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei 10617, Taiwan
| | - Toshio Kasai
- Department of Chemistry, National Taiwan University, Taipei 10617, Taiwan.,Institute of Scientific and Industrial Research, Osaka University, Ibaraki, Osaka 567-0047, Japan
| | - Vincenzo Aquilanti
- Dipartimento di Chimica, Biologia e Biotecnologie, Università di Perugia, Perugia 06123, Italy.,Istituto di Struttura della Materia, Consiglio Nazionale delle Ricerche, Rome 00016, Italy
| | - Federico Palazzetti
- Dipartimento di Chimica, Biologia e Biotecnologie, Università di Perugia, Perugia 06123, Italy
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7
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Roaming Dynamics and Conformational Memory in Photolysis of Formic Acid at 193 nm Using Time-resolved Fourier-transform Infrared Emission Spectroscopy. Sci Rep 2020; 10:4769. [PMID: 32179782 PMCID: PMC7075954 DOI: 10.1038/s41598-020-61642-7] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2019] [Accepted: 11/28/2019] [Indexed: 11/09/2022] Open
Abstract
In photodissociation of trans-formic acid (HCOOH) at 193 nm, we have observed two molecular channels of CO + H2O and CO2 + H2 by using 1 μs-resolved Fourier-transform infrared emission spectroscopy. With the aid of spectral simulation, the CO spectra are rotationally resolved for each vibrational state (v = 1-8). Each of the resulting vibrational and rotational population distributions is characteristic of two Boltzmann profiles with different temperatures, originating from either transition state pathway or OH-roaming to form the same CO + H2O products. The H2O roaming co-product is also spectrally simulated to understand the interplay with the CO product in the internal energy partitioning. Accordingly, this work has evaluated the internal energy disposal for the CO and H2O roaming products; especially the vibrational-state dependence of the roaming signature is reported for the first time. Further, given a 1 μs resolution, the temporal dependence of the CO/CO2 product ratio at v ≥ 1 rises from 3 to 10 of study, thereby characterizing the effect of conformational memory and well reconciling with the disputed results reported previously between absorption and emission methods.
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8
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Lanfri L, Wang YL, Pham TV, Nguyen NT, Paci MB, Lin MC, Lee YP. Infrared Emission from Photodissociation of Methyl Formate [HC(O)OCH3] at 248 and 193 nm: Absence of Roaming Signature. J Phys Chem A 2019; 123:6130-6143. [PMID: 31267746 DOI: 10.1021/acs.jpca.9b04129] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Lucia Lanfri
- Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Ala I - 2do
Piso Ciudad Universitaria, Pabellón, Argentina
| | - Yen-Lin Wang
- Department of Applied Chemistry and Institute of Molecular Science, National Chiao Tung University, Hsinchu 30010, Taiwan
| | - Tien V. Pham
- Department of Applied Chemistry and Institute of Molecular Science, National Chiao Tung University, Hsinchu 30010, Taiwan
- School of Chemical Engineering, Hanoi University of Science and Technology, Hanoi, Vietnam
| | - Nghia Trong Nguyen
- School of Chemical Engineering, Hanoi University of Science and Technology, Hanoi, Vietnam
- Center for Emergent Functional Matter Science, National Chiao Tung University, Hsinchu 30010, Taiwan
| | - Maxi Burgos Paci
- Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Ala I - 2do
Piso Ciudad Universitaria, Pabellón, Argentina
| | - M. C. Lin
- Department of Applied Chemistry and Institute of Molecular Science, National Chiao Tung University, Hsinchu 30010, Taiwan
- Center for Emergent Functional Matter Science, National Chiao Tung University, Hsinchu 30010, Taiwan
| | - Yuan-Pern Lee
- Department of Applied Chemistry and Institute of Molecular Science, National Chiao Tung University, Hsinchu 30010, Taiwan
- Center for Emergent Functional Matter Science, National Chiao Tung University, Hsinchu 30010, Taiwan
- Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei 10617, Taiwan
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9
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Sutradhar S, Samanta BR, Fernando R, Reisler H. Spectroscopy and Two-Photon Dissociation of Jet-Cooled Pyruvic Acid. J Phys Chem A 2019; 123:5906-5917. [DOI: 10.1021/acs.jpca.9b04166] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Subhasish Sutradhar
- Department of Chemistry, University of Southern California, Los Angeles, California 90089-0482, United States
| | - Bibek R. Samanta
- Department of Chemistry, University of Southern California, Los Angeles, California 90089-0482, United States
| | - Ravin Fernando
- Department of Chemistry, University of Southern California, Los Angeles, California 90089-0482, United States
| | - Hanna Reisler
- Department of Chemistry, University of Southern California, Los Angeles, California 90089-0482, United States
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10
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Ma Y, Liu J, Li F, Wang F, Kitsopoulos TN. Roaming Dynamics in the Photodissociation of Formic Acid at 230 nm. J Phys Chem A 2019; 123:3672-3677. [PMID: 30969120 DOI: 10.1021/acs.jpca.9b00724] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Roaming dynamics is observed in the photodissociation of formic acid (HCOOH) at 230 nm by using the slice imaging method. In combination with rotational state selective (2 + 1) resonance-enhanced multiphoton ionization of the CO fragments, the speed distributions of the CO fragments exhibit a low recoil velocity at low rotational levels of J = 9 and 20, while the velocity distributions of CO at high rotational levels of J = 30 and 48 show a relatively large recoil velocity. The experimental results indicate that the roaming of OH radical should be related with the formation of CO + H2O channel at the present photolysis energy. Unlike the roaming pathways occurring in H2CO that can be described by loose flat potential, our CO speed distribution analysis suggests the presence of a "tight" flat potential in the roaming dynamics of HCOOH molecules.
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Affiliation(s)
- Yujie Ma
- Department of Chemistry and Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials, Collaborative Innovation Centre of Chemistry for Energy Materials , Fudan University , Shanghai 200433 , P. R. China
| | - Jiaxing Liu
- Department of Chemistry and Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials, Collaborative Innovation Centre of Chemistry for Energy Materials , Fudan University , Shanghai 200433 , P. R. China
| | - Fangfang Li
- Department of Chemistry and Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials, Collaborative Innovation Centre of Chemistry for Energy Materials , Fudan University , Shanghai 200433 , P. R. China
| | - Fengyan Wang
- Department of Chemistry and Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials, Collaborative Innovation Centre of Chemistry for Energy Materials , Fudan University , Shanghai 200433 , P. R. China
| | - Theofanis N Kitsopoulos
- Department of Dynamics at Surfaces, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany; Institute of Electronic Structure and Laser, FORTH, Heraklion, Greece; Department of Chemistry , University of Crete , Heraklion , Greece
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11
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Ekanayake N, Severt T, Nairat M, Weingartz NP, Farris BM, Kaderiya B, Feizollah P, Jochim B, Ziaee F, Borne K, Raju P K, Carnes KD, Rolles D, Rudenko A, Levine BG, Jackson JE, Ben-Itzhak I, Dantus M. H 2 roaming chemistry and the formation of H 3+ from organic molecules in strong laser fields. Nat Commun 2018; 9:5186. [PMID: 30518927 PMCID: PMC6281587 DOI: 10.1038/s41467-018-07577-0] [Citation(s) in RCA: 52] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2018] [Accepted: 11/06/2018] [Indexed: 11/11/2022] Open
Abstract
Roaming mechanisms, involving the brief generation of a neutral atom or molecule that stays in the vicinity before reacting with the remaining atoms of the precursor, are providing valuable insights into previously unexplained chemical reactions. Here, the mechanistic details and femtosecond time-resolved dynamics of H3+ formation from a series of alcohols with varying primary carbon chain lengths are obtained through a combination of strong-field laser excitation studies and ab initio molecular dynamics calculations. For small alcohols, four distinct pathways involving hydrogen migration and H2 roaming prior to H3+ formation are uncovered. Despite the increased number of hydrogens and possible combinations leading to H3+ formation, the yield decreases as the carbon chain length increases. The fundamental mechanistic findings presented here explore the formation of H3+, the most important ion in interstellar chemistry, through H2 roaming occurring in ionic species. H2 roaming is associated with H3+ formation when certain organic molecules are exposed to strong laser fields. Here, the mechanistic details and time-resolved dynamics of H3+ formation from a series of alcohols were obtained and found that the product yield decreases as the carbon chain length increases.
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Affiliation(s)
- Nagitha Ekanayake
- Department of Chemistry, Michigan State University, East Lansing, MI, 48824, USA
| | - Travis Severt
- J. R. Macdonald Laboratory, Physics Department, Kansas State University, Manhattan, KS, 66506, USA
| | - Muath Nairat
- Department of Chemistry, Michigan State University, East Lansing, MI, 48824, USA
| | - Nicholas P Weingartz
- Department of Chemistry, Michigan State University, East Lansing, MI, 48824, USA
| | - Benjamin M Farris
- Department of Chemistry, Michigan State University, East Lansing, MI, 48824, USA
| | - Balram Kaderiya
- J. R. Macdonald Laboratory, Physics Department, Kansas State University, Manhattan, KS, 66506, USA
| | - Peyman Feizollah
- J. R. Macdonald Laboratory, Physics Department, Kansas State University, Manhattan, KS, 66506, USA
| | - Bethany Jochim
- J. R. Macdonald Laboratory, Physics Department, Kansas State University, Manhattan, KS, 66506, USA
| | - Farzaneh Ziaee
- J. R. Macdonald Laboratory, Physics Department, Kansas State University, Manhattan, KS, 66506, USA
| | - Kurtis Borne
- J. R. Macdonald Laboratory, Physics Department, Kansas State University, Manhattan, KS, 66506, USA
| | - Kanaka Raju P
- J. R. Macdonald Laboratory, Physics Department, Kansas State University, Manhattan, KS, 66506, USA
| | - Kevin D Carnes
- J. R. Macdonald Laboratory, Physics Department, Kansas State University, Manhattan, KS, 66506, USA
| | - Daniel Rolles
- J. R. Macdonald Laboratory, Physics Department, Kansas State University, Manhattan, KS, 66506, USA
| | - Artem Rudenko
- J. R. Macdonald Laboratory, Physics Department, Kansas State University, Manhattan, KS, 66506, USA
| | - Benjamin G Levine
- Department of Chemistry, Michigan State University, East Lansing, MI, 48824, USA
| | - James E Jackson
- Department of Chemistry, Michigan State University, East Lansing, MI, 48824, USA
| | - Itzik Ben-Itzhak
- J. R. Macdonald Laboratory, Physics Department, Kansas State University, Manhattan, KS, 66506, USA
| | - Marcos Dantus
- Department of Chemistry, Michigan State University, East Lansing, MI, 48824, USA. .,Department of Physics and Astronomy, Michigan State University, East Lansing, MI, 48824, USA.
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12
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Coutinho ND, Sanches-Neto FO, Carvalho-Silva VH, de Oliveira HCB, Ribeiro LA, Aquilanti V. Kinetics of the OH+HCl→H 2 O+Cl reaction: Rate determining roles of stereodynamics and roaming and of quantum tunneling. J Comput Chem 2018; 39:2508-2516. [PMID: 30365178 DOI: 10.1002/jcc.25597] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2018] [Revised: 08/15/2018] [Accepted: 08/20/2018] [Indexed: 02/03/2023]
Abstract
The OH + HCl → H2 O + Cl reaction is one of the most studied four-body systems, extensively investigated by both experimental and theoretical approaches. Here, as a continuation of our previous work on the OH + HBr and OH + HI reactions, which manifest an anti-Arrhenius behavior that was explained by stereodynamic and roaming effects, we extend the strategy to understand the transition to the sub-Arrhenius behavior occurring for the HCl case. As previously, we perform first-principles on-the-fly Born-Oppenheimer molecular dynamics calculations, thermalized at four temperatures (50, 200, 350, and 500 K), but this time we also apply a high-level transition-state-theory, modified to account for tunneling conditions. We find that the theoretical rate constants calculated with Bell tunneling corrections are in good agreement with extensive experimental data available for this reaction in the ample temperature range: (i) simulations show that the roles of molecular orientation in promoting this reaction and of roaming in finding the favorable path are minor than in the HBr and HI cases, and (ii) dominating is the effect of quantum mechanical penetration through the energy barrier along the reaction path on the potential energy surface. The discussion of these results provides clarification of the origin on different non-Arrhenius mechanisms observed along this series of reactions. © 2018 Wiley Periodicals, Inc.
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Affiliation(s)
- Nayara D Coutinho
- Instituto de Química, Universidade de Brasília, Caixa Postal 4478, 70904-970, Brasília, Brazil
| | - Flavio O Sanches-Neto
- Grupo de Química Teórica e Estrutural de Anápolis, Ciências Exatas e Tecnológicas, Universidade Estadual de Goiás, CP 459, 75001-970, Anápolis, GO, Brazil
| | | | - Heibbe C B de Oliveira
- Instituto de Química, Universidade de Brasília, Caixa Postal 4478, 70904-970, Brasília, Brazil
| | - Luiz A Ribeiro
- Institute of Physics, University of Brasilia, Brasilia, 70910-900, Brazil
| | - Vincenzo Aquilanti
- Dipartimento di Chimica, Biologia e Biotecnologie, Università di Perugia, Via Elce di Sotto 8, 06123, Perugia, Italy.,Istituto di Struttura della Materia, Consiglio Nazionale delle Ricerche, Area dela Ricerca di Roma Tor Vergata, Via del Fosso del Cavaliere, 00133, Rome, Italy
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13
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Lin KC, Tsai PY, Chao MH, Nakamura M, Kasai T, Lombardi A, Palazzetti F, Aquilanti V. Roaming signature in photodissociation of carbonyl compounds. INT REV PHYS CHEM 2018. [DOI: 10.1080/0144235x.2018.1488951] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Affiliation(s)
- King-Chuen Lin
- Department of Chemistry, National Taiwan University, Taipei, Taiwan (ROC)
- Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei, Taiwan (ROC)
| | - Po-Yu Tsai
- Department of Chemistry, National Chung-Hsing University, Taichung, Taiwan (ROC)
| | - Meng-Hsuan Chao
- Department of Chemistry, National Taiwan University, Taipei, Taiwan (ROC)
| | - Masaaki Nakamura
- Department of Chemistry, National Taiwan University, Taipei, Taiwan (ROC)
| | - Toshio Kasai
- Department of Chemistry, National Taiwan University, Taipei, Taiwan (ROC)
- Institute of Scientific and Industrial Research, Osaka University, Osaka, Japan
| | - Andrea Lombardi
- Dipartimento di Chimica, Biologia e Biotecnologie, Università di Perugia, Perugia, Italy
- Consortium for Computational Molecular and Materials Sciences (CMS)2, Perugia, Italy
| | - Federico Palazzetti
- Dipartimento di Chimica, Biologia e Biotecnologie, Università di Perugia, Perugia, Italy
- Scuola Normale Superiore di Pisa, Pisa, Italy
| | - Vincenzo Aquilanti
- Dipartimento di Chimica, Biologia e Biotecnologie, Università di Perugia, Perugia, Italy
- Istituto di Struttura della Materia, Consiglio Nazionale delle Ricerche, Rome, Italy
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14
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Tsai PY. A generalized unimolecular impulsive model for curved reaction path. J Chem Phys 2018; 148:234101. [PMID: 29935512 DOI: 10.1063/1.5030488] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
This work aims to introduce a generalized impulsive model for unimolecular dissociation processes. This model allows us to take into account the curvature of the reaction path explicitly. It is a generalization of the previously developed multi-center impulsive model [P.-Y. Tsai and K.-C. Lin, J. Phys. Chem. A 119, 29 (2015)]. Several limitations of conventional impulsive models are eliminated by this study: (1) Unlike conventional impulsive models, in which a single molecular geometry is responsible for the impulse determination, the gradients on the whole dissociation path are taken into account. The model can treat dissociation pathways with large curvatures and loose saddle points. (2) The method can describe the vibrational excitation of polyatomic fragments due to the bond formation by multi-center impulse. (3) The available energy in conventional impulsive models is separated into uncoupled statistical and impulsive energy reservoirs, while the interplay between these reservoirs is allowed in the new model. (4) The quantum state correlation between fragments can be preserved in analysis. Dissociations of several molecular systems including the roaming pathways of formaldehyde, nitrate radical, acetaldehyde, and glyoxal are chosen as benchmarks. The predicted photofragment energy and vector distributions are consistent with the experimental results reported previously. In these examples, the capability of the new model to treat the curved dissociation path, loose saddle points, polyatomic fragments, and multiple-body dissociation is verified. As a cheaper computational tool with respect to ab initio on-the-fly direct dynamic simulations, this model can provide detailed information on the energy disposal, quantum state correlation, and stereodynamics in unimolecular dissociation processes.
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Affiliation(s)
- Po-Yu Tsai
- Department of Chemistry, National Chung Hsing University, Taichung 402, Taiwan
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15
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Kasai T, Che DC, Tsai PY, Nakamura M, Muthiah B, Lin KC. Roaming and chaotic behaviors in collisional and photo-initiated molecular-beam reactions: a role of classical vs. quantum nonadiabatic dynamics. RENDICONTI LINCEI. SCIENZE FISICHE E NATURALI 2018. [DOI: 10.1007/s12210-018-0709-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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16
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Falcinelli S, Vecchiocattivi F, Alagia M, Schio L, Richter R, Stranges S, Catone D, Arruda MS, Mendes LAV, Palazzetti F, Aquilanti V, Pirani F. Double photoionization of propylene oxide: A coincidence study of the ejection of a pair of valence-shell electrons. J Chem Phys 2018; 148:114302. [PMID: 29566526 DOI: 10.1063/1.5024408] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Propylene oxide, a favorite target of experimental and theoretical studies of circular dichroism, was recently discovered in interstellar space, further amplifying the attention to its role in the current debate on protobiological homochirality. In the present work, a photoelectron-photoion-photoion coincidence technique, using an ion-imaging detector and tunable synchrotron radiation in the 18.0-37.0 eV energy range, permits us (i) to observe six double ionization fragmentation channels, their relative yields being accounted for about two-thirds by the couple (C2H4+, CH2O+) and one-fifth by (C2H3+, CH3O+); (ii) to measure thresholds for their openings as a function of photon energy; and (iii) to unravel a pronounced bimodality for a kinetic-energy-released distribution, fingerprint of competitive non-adiabatic mechanisms.
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Affiliation(s)
- Stefano Falcinelli
- Dipartimento di Ingegneria Civile ed Ambientale, Università di Perugia, Via G. Duranti 93, 06125 Perugia, Italy
| | - Franco Vecchiocattivi
- Dipartimento di Ingegneria Civile ed Ambientale, Università di Perugia, Via G. Duranti 93, 06125 Perugia, Italy
| | - Michele Alagia
- IOM-CNR Tasc, Km 163.5, Area Science Park, 34149 Basovizza, Trieste, Italy
| | - Luca Schio
- IOM-CNR Tasc, Km 163.5, Area Science Park, 34149 Basovizza, Trieste, Italy
| | - Robert Richter
- Elettra-Sincrotrone Trieste, Area Science Park, 34149 Basovizza, Trieste, Italy
| | - Stefano Stranges
- IOM-CNR Tasc, Km 163.5, Area Science Park, 34149 Basovizza, Trieste, Italy
| | - Daniele Catone
- Istituto di Struttura della Materia (CNR-ISM), Area della Ricerca di Roma Tor Vergata, Via del Fosso del Cavaliere, 100-00133 Roma, Italy
| | - Manuela S Arruda
- Dipartimento di Chimica, Biologia e Biotecnologie, Università di Perugia, Via Elce di Sotto 8, 06123 Perugia, Italy
| | - Luiz A V Mendes
- Instituto de Fìsica, Universidade Federal da Bahia, Campus Universitario de Ondina, 40210-340 Salvador, BA, Brazil
| | - Federico Palazzetti
- Dipartimento di Chimica, Biologia e Biotecnologie, Università di Perugia, Via Elce di Sotto 8, 06123 Perugia, Italy
| | - Vincenzo Aquilanti
- Istituto di Struttura della Materia (CNR-ISM), Area della Ricerca di Roma Tor Vergata, Via del Fosso del Cavaliere, 100-00133 Roma, Italy
| | - Fernando Pirani
- Dipartimento di Chimica, Biologia e Biotecnologie, Università di Perugia, Via Elce di Sotto 8, 06123 Perugia, Italy
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17
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Abstract
The phenomenon of roaming in chemical reactions has now become both commonly observed in experiment and extensively supported by theory and simulations. Roaming occurs in highly-excited molecules when the trajectories of atomic motion often bypass the minimum energy pathway and produce reaction in unexpected ways from unlikely geometries. The prototypical example is the unimolecular dissociation of formaldehyde (H2CO), in which the "normal" reaction proceeds through a tight transition state to yield H2 + CO but for which a high fraction of dissociations take place via a "roaming" mechanism in which one H atom moves far from the HCO, almost to dissociation, and then returns to abstract the second H atom. We review below the theories and simulations that have recently been developed to address and understand this new reaction phenomenon.
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Affiliation(s)
- Joel M Bowman
- Department of Chemistry and Cherry L. Emerson Center for Scientific Computation, Emory University Atlanta, Georgia 30322, USA.
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18
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Nakamura M, Yang SJ, Lin KC, Kasai T, Che DC, Lombardi A, Palazzetti F, Aquilanti V. Stereodirectional images of molecules oriented by a variable-voltage hexapolar field: Fragmentation channels of 2-bromobutane electronically excited at two photolysis wavelengths. J Chem Phys 2017; 147:013917. [DOI: 10.1063/1.4981025] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Affiliation(s)
- Masaaki Nakamura
- Department of Chemistry, National Taiwan University, Taipei 10617, Taiwan
| | - Shiun-Jr Yang
- Department of Chemistry, National Taiwan University, Taipei 10617, Taiwan
| | - King-Chuen Lin
- Department of Chemistry, National Taiwan University, Taipei 10617, Taiwan
- Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei 10617, Taiwan
| | - Toshio Kasai
- Department of Chemistry, National Taiwan University, Taipei 10617, Taiwan
- Institute of Scientific and Industrial Research, Osaka University, Ibaraki, Osaka 567-0047, Japan
| | - Dock-Chil Che
- Department of Chemistry, Graduate School of Science, Osaka University, Toyonaka, Osaka 560-0043, Japan
| | - Andrea Lombardi
- Università di Perugia, Dipartimento di Chimica, Biologia e Biotecnologie, 06123 Perugia, Italy
| | - Federico Palazzetti
- Università di Perugia, Dipartimento di Chimica, Biologia e Biotecnologie, 06123 Perugia, Italy
| | - Vincenzo Aquilanti
- Università di Perugia, Dipartimento di Chimica, Biologia e Biotecnologie, 06123 Perugia, Italy
- Istituto di Struttura della Materia, Consiglio Nazionale delle Ricerche, 00016 Rome, Italy
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19
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Coutinho ND, Aquilanti V, Silva VHC, Camargo AJ, Mundim KC, de Oliveira HCB. Stereodirectional Origin of anti-Arrhenius Kinetics for a Tetraatomic Hydrogen Exchange Reaction: Born-Oppenheimer Molecular Dynamics for OH + HBr. J Phys Chem A 2016; 120:5408-17. [PMID: 27205872 DOI: 10.1021/acs.jpca.6b03958] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Among four-atom processes, the reaction OH + HBr → H2O + Br is one of the most studied experimentally: its kinetics has manifested an unusual anti-Arrhenius behavior, namely, a marked decrease of the rate constant as the temperature increases, which has intrigued theoreticians for a long time. Recently, salient features of the potential energy surface have been characterized and most kinetic aspects can be considered as satisfactorily reproduced by classical trajectory simulations. Motivation of the work reported in this paper is the investigation of the stereodirectional dynamics of this reaction as the prominent reason for the peculiar kinetics: we started in a previous Letter ( J. Phys. Chem. Lett. 2015 , 6 , 1553 - 1558 ) a first-principles Born-Oppenheimer "canonical" molecular dynamics approach. Trajectories are step-by-step generated on a potential energy surface quantum mechanically calculated on-the-fly and are thermostatically equilibrated to correspond to a specific temperature. Here, refinements of the method permitted a major increase of the number of trajectories and the consideration of four temperatures -50, +200, +350, and +500 K, for which the sampling of initial conditions allowed us to characterize the stereodynamical effect. The role is documented of the adjustment of the reactants' mutual orientation to encounter the entrance into the "cone of acceptance" for reactivity. The aperture angle of this cone is dictated by a range of directions of approach compatible with the formation of the specific HOH angle of the product water molecule; and consistently the adjustment is progressively less effective the higher the kinetic energy. Qualitatively, this emerging picture corroborates experiments on this reaction, involving collisions of aligned and oriented molecular beams, and covering a range of energies higher than the thermal ones. The extraction of thermal rate constants from this molecular dynamics approach is discussed and the systematic sampling of the canonical ensemble is indicated as needed for quantitative comparison with the kinetic experiments.
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Affiliation(s)
- Nayara D Coutinho
- Instituto de Química, Universidade de Brasília , 4478, 70904-970 Brasília, Brazil
| | - Vincenzo Aquilanti
- Dipartimento di Chimica, Biologia e Biotecnologie, Università di Perugia , Via Elce di Sotto 8, 06123, Perugia, Italy.,Instituto de Física, Universidade Federal da Bahia , 40210 Salvador, Brazil.,Istituto di Struttura della Materia, Consiglio Nazionale delle Ricerche , 00016 Rome, Italy
| | - Valter H C Silva
- Grupo de Química Teórica e Estrutural de Anápolis, Ciências Exatas e Tecnológicas, Universidade Estadual de Goiás , 0459, 75001-970 Anápolis, GO Brazil
| | - Ademir J Camargo
- Grupo de Química Teórica e Estrutural de Anápolis, Ciências Exatas e Tecnológicas, Universidade Estadual de Goiás , 0459, 75001-970 Anápolis, GO Brazil
| | - Kleber C Mundim
- Instituto de Química, Universidade de Brasília , 4478, 70904-970 Brasília, Brazil
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20
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Sun Z, Yang C, Zheng Y. Laser-induced dissociation dynamics of triatomic molecule in electronic excited states: A full-dimensional quantum mechanics study. J Chem Phys 2016; 143:224309. [PMID: 26671377 DOI: 10.1063/1.4936832] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
We present a detailed theoretical approach to investigate the laser-induced dissociation dynamics of a triatomic molecule on its electronic excited state in full dimensional case. In this method, the time evolution of the time-dependent system is propagated via combined the split operator method and the expansion of Chebyshev polynomials (or short-time Chebyshev propagation) and the system wave functions are expanded in terms of molecular rotational bases. As an example of the application of this formalism, the dissociation dynamics of H3(+)→H2(+)+H induced by ultrashort UV laser pulses are investigated on new Born-Oppenheimer potential energy surfaces. Our numerical results show that the signals of dissociation products will be easier to observe as the increasing of field strength. Driving by a 266 nm laser beam, the calculated central value of kinetic-energy-release is 2.04 eV which shows excellent agreement with the experimental estimation of 2.1 eV. When the H3(+) ion is rotationally excited, the spatial distribution of product fragments will become well converged.
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Affiliation(s)
- Zhaopeng Sun
- School of Physics, Shandong University, Jinan 250100, China
| | - Chuanlu Yang
- School of Physics and Optoelectronic Engineering, Ludong University, Yantai 264025, China
| | - Yujun Zheng
- School of Physics, Shandong University, Jinan 250100, China
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21
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Lombardi A, Palazzetti F, Aquilanti V, Li HK, Tsai PY, Kasai T, Lin KC. Rovibrationally Excited Molecules on the Verge of a Triple Breakdown: Molecular and Roaming Mechanisms in the Photodecomposition of Methyl Formate. J Phys Chem A 2016; 120:5155-62. [DOI: 10.1021/acs.jpca.6b00723] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Affiliation(s)
- Andrea Lombardi
- Dipartimento
di Chimica, Biologia e Biotecnologie, Università di Perugia, Via Elce
di Sotto 8, 06123 Perugia, Italy
| | - Federico Palazzetti
- Dipartimento
di Chimica, Biologia e Biotecnologie, Università di Perugia, Via Elce
di Sotto 8, 06123 Perugia, Italy
| | - Vincenzo Aquilanti
- Dipartimento
di Chimica, Biologia e Biotecnologie, Università di Perugia, Via Elce
di Sotto 8, 06123 Perugia, Italy
- Istituto
di Struttura della Materia, Consiglio Nazionale delle Ricerche, Rome, Italy
- Instituto
de Fisica, Universidade Federal da Bahia, Salvador, Brazil
| | - Hou-Kuan Li
- Department
of Chemistry, National Taiwan University, Taipei 106, Taiwan
| | - Po-Yu Tsai
- Department
of Chemistry, National Taiwan University, Taipei 106, Taiwan
| | - Toshio Kasai
- Department
of Chemistry, National Taiwan University, Taipei 106, Taiwan
| | - King-Chuen Lin
- Department
of Chemistry, National Taiwan University, Taipei 106, Taiwan
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22
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Houston PL, Conte R, Bowman JM. Roaming Under the Microscope: Trajectory Study of Formaldehyde Dissociation. J Phys Chem A 2016; 120:5103-14. [DOI: 10.1021/acs.jpca.6b00488] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Paul L. Houston
- School
of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, Georgia 30332, United States
- Department
of Chemistry and Chemical Biology, Cornell University, Baker Laboratory, Ithaca, New York 14852, United States
| | - Riccardo Conte
- Department
of Chemistry and Cherry L. Emerson Center for Scientific Computation, Emory University, Atlanta, Georgia 30322, United States
- Dipartimento
di Chimica, Università degli Studi di Milano, 20133 Milano, Italy
| | - Joel M. Bowman
- Department
of Chemistry and Cherry L. Emerson Center for Scientific Computation, Emory University, Atlanta, Georgia 30322, United States
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23
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Lin KC. Regulation of nonadiabatic processes in the photolysis of some carbonyl compounds. Phys Chem Chem Phys 2016; 18:6980-95. [DOI: 10.1039/c5cp07012k] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
An energy scheme involving So → S1 excitation, followed by dissociation channels via diabatic coupling, internal conversion, transition state and roaming mechanisms.
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Affiliation(s)
- King-Chuen Lin
- Department of Chemistry
- National Taiwan University
- Taipei 106
- Taiwan
- Institute of Atomic and Molecular Sciences
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24
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Stephansen AB, Larsen MAB, Sølling TI. The involvement of triplet receiver states in the ultrafast excited state processes of small esters. Phys Chem Chem Phys 2016; 18:24484-97. [DOI: 10.1039/c6cp04046b] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The photoinduced processes of methyl formate and methyl acetate have been probed by femtosecond time-resolved mass spectrometry and photoelectron spectroscopy experiments supported by quantum chemical calculations.
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Affiliation(s)
- A. B. Stephansen
- Department of Chemistry
- Københavns Universitet Det Natur- og Biovidenskabelige Fakultet
- København Ø
- Denmark
| | - M. A. B. Larsen
- Department of Chemistry
- Københavns Universitet Det Natur- og Biovidenskabelige Fakultet
- København Ø
- Denmark
| | - T. I. Sølling
- Department of Chemistry
- Københavns Universitet Det Natur- og Biovidenskabelige Fakultet
- København Ø
- Denmark
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25
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Jiménez E, Antiñolo M, Ballesteros B, Canosa A, Albaladejo J. First evidence of the dramatic enhancement of the reactivity of methyl formate (HC(O)OCH3) with OH at temperatures of the interstellar medium: a gas-phase kinetic study between 22 K and 64 K. Phys Chem Chem Phys 2016; 18:2183-91. [DOI: 10.1039/c5cp06369h] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The gas phase chemistry of neutral-neutral reactions of interest in the interstellar medium (ISM) is poorly understood.
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Affiliation(s)
- E. Jiménez
- Departamento de Química Física
- Facultad de Ciencias y Tecnologías Químicas
- Universidad de Castilla-La Mancha
- 13071 Ciudad Real
- Spain
| | - M. Antiñolo
- Departamento de Química Física
- Facultad de Ciencias y Tecnologías Químicas
- Universidad de Castilla-La Mancha
- 13071 Ciudad Real
- Spain
| | - B. Ballesteros
- Departamento de Química Física
- Facultad de Ciencias y Tecnologías Químicas
- Universidad de Castilla-La Mancha
- 13071 Ciudad Real
- Spain
| | - A. Canosa
- Département de Physique Moléculaire
- Institut de Physique de Rennes
- UMR CNRS-UR1 6251
- Université de Rennes 1
- 35042 Rennes Cedex
| | - J. Albaladejo
- Departamento de Química Física
- Facultad de Ciencias y Tecnologías Químicas
- Universidad de Castilla-La Mancha
- 13071 Ciudad Real
- Spain
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26
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Nakamura M, Tsai PY, Kasai T, Lin KC, Palazzetti F, Lombardi A, Aquilanti V. Dynamical, spectroscopic and computational imaging of bond breaking in photodissociation: roaming and role of conical intersections. Faraday Discuss 2015; 177:77-98. [PMID: 25625792 DOI: 10.1039/c4fd00174e] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Recent experimental and theoretical advances in the study of the dissociation of excited molecules are revealing unexpected mechanisms, when their outcomes are tackled by combining (i) space-time ion imaging of translational features, with (ii) spectroscopic probing of rotational and vibrational distributions; crucial is the assistance of (iii) the quantum chemistry of structural investigations of rearrangements of chemical bonds, and of (iv) the simulations of molecular dynamics to follow the evolution of selective bond stretching and breaking. Here we present results of such an integrated approach to methyl formate, HCOOCH3, the simplest of esters; the main focus is on the rotovibrationally excited CO (v=1) product and in general on the energy distribution in the fragments. Previous laser studies of dissociation into CO and CH3OH at a sequence of various wavelengths discovered signatures of a roaming mechanism by the late arrival of CO (v=0) products in time-of-flight ion imaging. Subsequent detailed investigations as a function of excitation energy provided the assessment of the threshold, which opens for triple breakdown into CO and further fragments H and CH3O, as spectroscopically characterized by ion imaging and FTIR respectively. Accompanying quantum mechanical electronic structure calculations and classical molecular dynamics simulations clarify the origin of these fragments through "roaming" pathways involving incipient radical intermediates at energies below the triple fragmentation threshold: a specific role is played by nonadiabatic transitions at a conical intersection between ground and excited states; alternative pathways focalize our attention to regions of the potential energy surfaces other than those in the neighbourhoods of saddle points along minimum energy paths: eventually this leads us to look for avenues in reaction kinetics beyond those of venerable transition state theories.
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Affiliation(s)
- Masaaki Nakamura
- Department of Chemistry, National Taiwan University, Taipei 106, Taiwan.
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27
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Coutinho ND, Silva VHC, de Oliveira HCB, Camargo AJ, Mundim KC, Aquilanti V. Stereodynamical Origin of Anti-Arrhenius Kinetics: Negative Activation Energy and Roaming for a Four-Atom Reaction. J Phys Chem Lett 2015; 6:1553-8. [PMID: 26263312 DOI: 10.1021/acs.jpclett.5b00384] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
The OH + HBr → H2O + Br reaction, prototypical of halogen-atom liberating processes relevant to mechanisms for atmospheric ozone destruction, attracted frequent attention of experimental chemical kinetics: the nature of the unusual reactivity drop from low to high temperatures eluded a variety of theoretical efforts, ranking this one among the most studied four-atom reactions. Here, inspired by oriented molecular-beams experiments, we develop a first-principles stereodynamical approach. Thermalized sets of trajectories, evolving on a multidimensional potential energy surface quantum mechanically generated on-the-fly, provide a map of most visited regions at each temperature. Visualizations of rearrangements of bonds along trajectories and of the role of specific angles of reactants' mutual approach elucidate the mechanistic change from the low kinetic energy regime (where incident reactants reorient to find the propitious alignment leading to reaction) to high temperature (where speed hinders adjustment of directionality and roaming delays reactivity).
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Affiliation(s)
- Nayara D Coutinho
- †Unidade Universitária de Ciências Exatas e Tecnológicas, 75001-970, Anápolis, and Unidade de Ipameri, Ipameri, Universidade Estadual de Goiás, 75780-000 Goiás, Brazil
- ‡Instituto de Química, Universidade de Brasília, Caixa Postal 4478, 70904-970 Brasília, Brazil
| | - Valter H C Silva
- †Unidade Universitária de Ciências Exatas e Tecnológicas, 75001-970, Anápolis, and Unidade de Ipameri, Ipameri, Universidade Estadual de Goiás, 75780-000 Goiás, Brazil
| | - Heibbe C B de Oliveira
- ‡Instituto de Química, Universidade de Brasília, Caixa Postal 4478, 70904-970 Brasília, Brazil
| | - Ademir J Camargo
- †Unidade Universitária de Ciências Exatas e Tecnológicas, 75001-970, Anápolis, and Unidade de Ipameri, Ipameri, Universidade Estadual de Goiás, 75780-000 Goiás, Brazil
| | - Kleber C Mundim
- ‡Instituto de Química, Universidade de Brasília, Caixa Postal 4478, 70904-970 Brasília, Brazil
| | - Vincenzo Aquilanti
- §Dipartimento di Chimica, Biologia e Biotecnologie, Università di Perugia, Via Elce di Sotto 8, 06123 Perugia, Italy
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28
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Li HK, Tsai PY, Hung KC, Kasai T, Lin KC. Communication: Photodissociation of CH3CHO at 308 nm: Observation of H-roaming, CH3-roaming, and transition state pathways together along the ground state surface. J Chem Phys 2015; 142:041101. [DOI: 10.1063/1.4906457] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Hou-Kuan Li
- Department of Chemistry, National Taiwan University, Taipei 106, Taiwan and Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei 106, Taiwan
| | - Po-Yu Tsai
- Department of Chemistry, National Taiwan University, Taipei 106, Taiwan and Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei 106, Taiwan
| | - Kai-Chan Hung
- Department of Chemistry, National Taiwan University, Taipei 106, Taiwan and Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei 106, Taiwan
| | - Toshio Kasai
- Department of Chemistry, National Taiwan University, Taipei 106, Taiwan and Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei 106, Taiwan
| | - King-Chuen Lin
- Department of Chemistry, National Taiwan University, Taipei 106, Taiwan and Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei 106, Taiwan
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29
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Tsai PY, Lin KC. Insight into photofragment vector correlation by a multi-center impulsive model. Phys Chem Chem Phys 2015; 17:19592-601. [DOI: 10.1039/c5cp03079j] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A multi-center impulsive model has been recently developed to characterize the dynamic feature of fragment vector correlation in photodissociation of formaldehyde, H2CO → CO + H2, via both transition state and roaming pathways.
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Affiliation(s)
- Po-Yu Tsai
- Department of Chemistry
- National Chung Hsing University
- Taichung 402
- Taiwan
| | - King-Chuen Lin
- Department of Chemistry
- National Taiwan University
- and Institute of Atomic and Molecular Sciences
- Taipei 106
- Taiwan
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30
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Tsai PY, Li HK, Kasai T, Lin KC. Roaming as the dominant mechanism for molecular products in the photodissociation of large aliphatic aldehydes. Phys Chem Chem Phys 2015; 17:23112-20. [DOI: 10.1039/c5cp03408f] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Photodissociation of isobutyraldehyde (C3H7CHO) at 248 nm is investigated using time-resolved Fourier-transform infrared emission spectroscopy to demonstrate the growing importance of the roaming pathway with increasing molecular size of aliphatic aldehydes.
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Affiliation(s)
- Po-Yu Tsai
- Department of Chemistry
- National Chung Hsing University
- Taichung 402
- Taiwan
| | - Hou-Kuan Li
- Department of Chemistry
- National Taiwan University
- and Institute of Atomic and Molecular Sciences
- Academia Sinica
- Taipei 106
| | - Toshio Kasai
- Department of Chemistry
- National Taiwan University
- and Institute of Atomic and Molecular Sciences
- Academia Sinica
- Taipei 106
| | - King-Chuen Lin
- Department of Chemistry
- National Taiwan University
- and Institute of Atomic and Molecular Sciences
- Academia Sinica
- Taipei 106
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31
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Tsai PY, Lin KC. Insight into the Photodissociation Dynamical Feature of Conventional Transition State and Roaming Pathways by an Impulsive Model. J Phys Chem A 2014; 119:29-38. [DOI: 10.1021/jp511000t] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Po-Yu Tsai
- Department
of Chemistry, National Taiwan University, and Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei 106, Taiwan
| | - King-Chuen Lin
- Department
of Chemistry, National Taiwan University, and Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei 106, Taiwan
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32
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Affiliation(s)
- Joel M. Bowman
- Department of Chemistry, Emory University, Atlanta, GA, USA
- Cherry L. Emerson Center for Scientific Computation, Emory University, Atlanta, GA, USA
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33
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Hung KC, Tsai PY, Li HK, Lin KC. Photodissociation of CH3CHO at 248 nm by time-resolved Fourier-transform infrared emission spectroscopy: Verification of roaming and triple fragmentation. J Chem Phys 2014; 140:064313. [DOI: 10.1063/1.4862266] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
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34
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Tsai PY, Hung KC, Li HK, Lin KC. Photodissociation of Propionaldehyde at 248 nm: Roaming Pathway as an Increasingly Important Role in Large Aliphatic Aldehydes. J Phys Chem Lett 2014; 5:190-195. [PMID: 26276201 DOI: 10.1021/jz402329g] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Time-resolved Fourier transform infrared emission spectroscopy is employed in the photolysis of propionaldehyde (CH3CH2CHO) at 248 nm to characterize the role of the roaming pathway. High-resolution spectra of CO are analyzed to yield a single Boltzmann rotational distribution for each vibrational level (ν = 1-4) with small rotational and large vibrational energy disposals. A roaming saddle point is found containing two far separated moieties of HCO and CH3CH2 with a weak interaction between them. Quasiclassical trajectory calculations on this configuration yield the CO energy flow behavior, consistent with the findings. The rate constant along the roaming pathway is evaluated to be larger by >1-2 orders of magnitude than those along tight transition state or three-body dissociation pathways. This work implies that the roaming mechanism plays an increasingly important role in aliphatic aldehydes as the molecular size becomes larger.
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Affiliation(s)
- Po-Yu Tsai
- Department of Chemistry, National Taiwan University and Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei 106, Taiwan
| | - Kai-Chan Hung
- Department of Chemistry, National Taiwan University and Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei 106, Taiwan
| | - Hou-Kuan Li
- Department of Chemistry, National Taiwan University and Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei 106, Taiwan
| | - King-Chuen Lin
- Department of Chemistry, National Taiwan University and Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei 106, Taiwan
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35
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Kasai T, Che DC, Okada M, Tsai PY, Lin KC, Palazzetti F, Aquilanti V. Directions of chemical change: experimental characterization of the stereodynamics of photodissociation and reactive processes. Phys Chem Chem Phys 2014; 16:9776-90. [DOI: 10.1039/c4cp00464g] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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