1
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Fidler AP, Chen L, McKillop AM, Weichman ML. Ultrafast dynamics of CN radical reactions with chloroform solvent under vibrational strong coupling. J Chem Phys 2023; 159:164302. [PMID: 37870135 DOI: 10.1063/5.0167410] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2023] [Accepted: 08/21/2023] [Indexed: 10/24/2023] Open
Abstract
Polariton chemistry may provide a new means to control molecular reactivity, permitting remote, reversible modification of reaction energetics, kinetics, and product yields. A considerable body of experimental and theoretical work has already demonstrated that strong coupling between a molecular vibrational mode and the confined electromagnetic field of an optical cavity can alter chemical reactivity without external illumination. However, the mechanisms underlying cavity-altered chemistry remain unclear in large part because the experimental systems examined previously are too complex for detailed analysis of their reaction dynamics. Here, we experimentally investigate photolysis-induced reactions of cyanide radicals with strongly-coupled chloroform (CHCl3) solvent molecules and examine the intracavity rates of photofragment recombination, solvent complexation, and hydrogen abstraction. We use a microfluidic optical cavity fitted with dichroic mirrors to facilitate vibrational strong coupling (VSC) of the C-H stretching mode of CHCl3 while simultaneously permitting optical access at visible wavelengths. Ultrafast transient absorption experiments performed with cavities tuned on- and off-resonance reveal that VSC of the CHCl3 C-H stretching transition does not significantly modify any measured rate constants, including those associated with the hydrogen abstraction reaction. This work represents, to the best of our knowledge, the first experimental study of an elementary bimolecular reaction under VSC. We discuss how the conspicuous absence of cavity-altered effects in this system may provide insights into the mechanisms of modified ground state reactivity under VSC and help bridge the divide between experimental results and theoretical predictions in vibrational polariton chemistry.
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Affiliation(s)
- Ashley P Fidler
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, USA
| | - Liying Chen
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, USA
| | | | - Marissa L Weichman
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, USA
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2
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Schulz A, Surkau J. Main group cyanides: from hydrogen cyanide to cyanido-complexes. REV INORG CHEM 2022. [DOI: 10.1515/revic-2021-0044] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Abstract
Homoleptic cyanide compounds exist of almost all main group elements. While the alkali metals and alkaline earth metals form cyanide salts, the cyanides of the lighter main group elements occur mainly as covalent compounds. This review gives an overview of the status quo of main group element cyanides and cyanido complexes. Information about syntheses are included as well as applications, special substance properties, bond lengths, spectroscopic characteristics and computations. Cyanide chemistry is presented mainly from the field of inorganic chemistry, but aspects of chemical biology and astrophysics are also discussed in relation to cyano compounds.
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Affiliation(s)
- Axel Schulz
- Chemie , Universität Rostock , Albert-Einstein-Straße 3a, 18059 Rostock , Mecklenburg-Vorpommern , Germany
| | - Jonas Surkau
- Chemie , Universität Rostock , Albert-Einstein-Straße 3a, 18059 Rostock , Mecklenburg-Vorpommern , Germany
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3
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Molecular Dynamics Study of the Photodissociation of ICN in Ethanol: Effect of Solvent Polarity. J SOLUTION CHEM 2021. [DOI: 10.1007/s10953-021-01094-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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4
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Morzan UN, Videla PE, Soley MB, Nibbering ETJ, Batista VS. Vibronic Dynamics of Photodissociating ICN from Simulations of Ultrafast X‐Ray Absorption Spectroscopy. Angew Chem Int Ed Engl 2020. [DOI: 10.1002/ange.202007192] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Affiliation(s)
- Uriel N. Morzan
- Condensed Matter Section The Abdus Salam International Center for Theoretical Physics Strada Costiera 11 34151 Trieste Italy
- Department of Chemistry Yale University P.O. Box 208107 New Haven CT 06520-8107 USA
| | - Pablo E. Videla
- Department of Chemistry Yale University P.O. Box 208107 New Haven CT 06520-8107 USA
- Energy Sciences Institute Yale University P.O. Box 27394 West Haven CT 06516-7394 USA
| | - Micheline B. Soley
- Department of Chemistry Yale University P.O. Box 208107 New Haven CT 06520-8107 USA
- Department of Chemistry and Chemical Biology Harvard University 12 Oxford Street Cambridge MA 02138 USA
- Yale Quantum Institute Yale University P.O. Box 208334 New Haven CT 06520-8263 USA
| | - Erik T. J. Nibbering
- Max Born Institute for Nonlinear Optics and Short Pulse Spectroscopy Max Born Strasse 2A 12489 Berlin Germany
| | - Victor S. Batista
- Department of Chemistry Yale University P.O. Box 208107 New Haven CT 06520-8107 USA
- Energy Sciences Institute Yale University P.O. Box 27394 West Haven CT 06516-7394 USA
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5
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Morzan UN, Videla PE, Soley MB, Nibbering ETJ, Batista VS. Vibronic Dynamics of Photodissociating ICN from Simulations of Ultrafast X-Ray Absorption Spectroscopy. Angew Chem Int Ed Engl 2020; 59:20044-20048. [PMID: 32691867 PMCID: PMC7693200 DOI: 10.1002/anie.202007192] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2020] [Revised: 06/23/2020] [Indexed: 11/07/2022]
Abstract
Ultrafast UV-pump/soft-X-ray-probe spectroscopy is a subject of great interest since it can provide detailed information about dynamical photochemical processes with ultrafast resolution and atomic specificity. Here, we focus on the photodissociation of ICN in the 1 Π1 excited state, with emphasis on the transient response in the soft-X-ray spectral region as described by the ab initio spectral lineshape averaged over the nuclear wavepacket probability density. We find that the carbon K-edge spectral region reveals a rich transient response that provides direct insights into the dynamics of frontier orbitals during the I-CN bond cleavage process. The simulated UV-pump/soft-X-ray-probe spectra exhibit detailed dynamical information, including a time-domain signature for coherent vibration associated with the photogenerated CN fragment.
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Affiliation(s)
- Uriel N. Morzan
- Condensed Matter SectionThe Abdus Salam International Center for Theoretical PhysicsStrada Costiera 1134151TriesteItaly
- Department of ChemistryYale UniversityP.O. Box 208107New HavenCT06520-8107USA
| | - Pablo E. Videla
- Department of ChemistryYale UniversityP.O. Box 208107New HavenCT06520-8107USA
- Energy Sciences InstituteYale UniversityP.O. Box 27394West HavenCT06516-7394USA
| | - Micheline B. Soley
- Department of ChemistryYale UniversityP.O. Box 208107New HavenCT06520-8107USA
- Department of Chemistry and Chemical BiologyHarvard University12 Oxford StreetCambridgeMA02138USA
- Yale Quantum InstituteYale UniversityP.O. Box 208334New HavenCT06520-8263USA
| | - Erik T. J. Nibbering
- Max Born Institute for Nonlinear Optics and Short Pulse SpectroscopyMax Born Strasse 2A12489BerlinGermany
| | - Victor S. Batista
- Department of ChemistryYale UniversityP.O. Box 208107New HavenCT06520-8107USA
- Energy Sciences InstituteYale UniversityP.O. Box 27394West HavenCT06516-7394USA
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6
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Abstract
The dynamics of chemical reactions in liquid solutions are now amenable to direct study using ultrafast laser spectroscopy techniques and advances in computer simulation methods. The surrounding solvent affects the chemical reaction dynamics in numerous ways, which include: (i) formation of complexes between reactants and solvent molecules; (ii) modifications to transition state energies and structures relative to the reactants and products; (iii) coupling between the motions of the reacting molecules and the solvent modes, and exchange of energy; (iv) solvent caging of reactants and products; and (v) structural changes to the solvation shells in response to the changing chemical identity of the solutes, on timescales which may be slower than the reactive events. This article reviews progress in the study of bimolecular chemical reaction dynamics in solution, concentrating on reactions which occur on ground electronic states. It illustrates this progress with reference to recent experimental and computational studies, and considers how the various ways in which a solvent affects the chemical reaction dynamics can be unravelled. Implications are considered for research in fields such as mechanistic synthetic chemistry.
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Affiliation(s)
- Andrew J Orr-Ewing
- School of Chemistry, University of Bristol, Cantock's Close, Bristol BS8 1TS, UK.
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7
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Baldini E, Palmieri T, Rossi T, Oppermann M, Pomarico E, Auböck G, Chergui M. Interfacial Electron Injection Probed by a Substrate-Specific Excitonic Signature. J Am Chem Soc 2017; 139:11584-11589. [PMID: 28762734 DOI: 10.1021/jacs.7b06322] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Ultrafast interfacial electron transfer in sensitized solar cells has mostly been probed by visible-to-terahertz radiation, which is sensitive to the free carriers in the conduction band of the semiconductor substrate. Here, we demonstrate the use of deep-ultraviolet continuum pulses to probe the interfacial electron transfer, by detecting a specific excitonic transition in both N719-sensitized anatase TiO2 and wurtzite ZnO nanoparticles. Our results are compared to those obtained on bare nanoparticles upon above-gap excitation. We show that the signal upon electron injection from the N719 dye into TiO2 is dominated by long-range Coulomb screening of the final states of the excitonic transitions, whereas in sensitized ZnO it is dominated by phase-space filling. The present approach offers a possible route to detecting interfacial electron transfer in a broad class of systems, including other transition metal oxides or sensitizers.
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Affiliation(s)
- Edoardo Baldini
- Laboratory of Ultrafast Spectroscopy, ISIC and Lausanne Centre for Ultrafast Science (LACUS), École Polytechnique Fédérale de Lausanne , CH-1015 Lausanne, Switzerland
| | - Tania Palmieri
- Laboratory of Ultrafast Spectroscopy, ISIC and Lausanne Centre for Ultrafast Science (LACUS), École Polytechnique Fédérale de Lausanne , CH-1015 Lausanne, Switzerland
| | - Thomas Rossi
- Laboratory of Ultrafast Spectroscopy, ISIC and Lausanne Centre for Ultrafast Science (LACUS), École Polytechnique Fédérale de Lausanne , CH-1015 Lausanne, Switzerland
| | - Malte Oppermann
- Laboratory of Ultrafast Spectroscopy, ISIC and Lausanne Centre for Ultrafast Science (LACUS), École Polytechnique Fédérale de Lausanne , CH-1015 Lausanne, Switzerland
| | - Enrico Pomarico
- Laboratory of Ultrafast Spectroscopy, ISIC and Lausanne Centre for Ultrafast Science (LACUS), École Polytechnique Fédérale de Lausanne , CH-1015 Lausanne, Switzerland
| | - Gerald Auböck
- Laboratory of Ultrafast Spectroscopy, ISIC and Lausanne Centre for Ultrafast Science (LACUS), École Polytechnique Fédérale de Lausanne , CH-1015 Lausanne, Switzerland
| | - Majed Chergui
- Laboratory of Ultrafast Spectroscopy, ISIC and Lausanne Centre for Ultrafast Science (LACUS), École Polytechnique Fédérale de Lausanne , CH-1015 Lausanne, Switzerland
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8
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Coulter P, Grubb MP, Koyama D, Sazanovich IV, Greetham GM, Orr-Ewing AJ. Recombination, Solvation and Reaction of CN Radicals Following Ultraviolet Photolysis of ICN in Organic Solvents. J Phys Chem A 2015; 119:12911-23. [DOI: 10.1021/acs.jpca.5b10716] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Philip Coulter
- School
of Chemistry, University of Bristol, Cantock’s Close, Bristol BS8 1TS, U.K
| | - Michael P. Grubb
- School
of Chemistry, University of Bristol, Cantock’s Close, Bristol BS8 1TS, U.K
| | - Daisuke Koyama
- School
of Chemistry, University of Bristol, Cantock’s Close, Bristol BS8 1TS, U.K
| | - Igor V. Sazanovich
- Central
Laser Facility, Research Complex at Harwell, Science and Technology
Facilities Council, Rutherford Appleton Laboratory, Harwell Oxford, Didcot,
Oxfordshire, OX11 0QX, U.K
| | - Gregory M. Greetham
- Central
Laser Facility, Research Complex at Harwell, Science and Technology
Facilities Council, Rutherford Appleton Laboratory, Harwell Oxford, Didcot,
Oxfordshire, OX11 0QX, U.K
| | - Andrew J. Orr-Ewing
- School
of Chemistry, University of Bristol, Cantock’s Close, Bristol BS8 1TS, U.K
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9
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Koyama D, Coulter P, Grubb MP, Greetham GM, Clark IP, Orr-Ewing AJ. Reaction Dynamics of CN Radicals in Acetonitrile Solutions. J Phys Chem A 2015; 119:12924-34. [DOI: 10.1021/acs.jpca.5b10720] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Daisuke Koyama
- School
of Chemistry, University of Bristol, Cantock’s Close, Bristol BS8 1TS, U.K
| | - Philip Coulter
- School
of Chemistry, University of Bristol, Cantock’s Close, Bristol BS8 1TS, U.K
| | - Michael P. Grubb
- School
of Chemistry, University of Bristol, Cantock’s Close, Bristol BS8 1TS, U.K
| | - Gregory M. Greetham
- Central
Laser Facility, Research Complex at Harwell, Science and Technology
Facilities Council, Rutherford Appleton Laboratory, Harwell Oxford, Didcot, Oxfordshire OX11 0QX, U.K
| | - Ian P. Clark
- Central
Laser Facility, Research Complex at Harwell, Science and Technology
Facilities Council, Rutherford Appleton Laboratory, Harwell Oxford, Didcot, Oxfordshire OX11 0QX, U.K
| | - Andrew J. Orr-Ewing
- School
of Chemistry, University of Bristol, Cantock’s Close, Bristol BS8 1TS, U.K
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10
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11
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Dunning GT, Preston TJ, Greaves SJ, Greetham GM, Clark IP, Orr-Ewing AJ. Vibrational Excitation of Both Products of the Reaction of CN Radicals with Acetone in Solution. J Phys Chem A 2015; 119:12090-101. [PMID: 26192334 PMCID: PMC4685429 DOI: 10.1021/acs.jpca.5b05624] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Transient electronic and vibrational absorption spectroscopy unravel the mechanisms and dynamics of bimolecular reactions of CN radicals with acetone in deuterated chloroform solutions. The CN radicals are produced by ultrafast ultraviolet photolysis of dissolved ICN. Two reactive forms of CN radicals are distinguished by their electronic absorption bands: "free" (uncomplexed) CN radicals, and "solvated" CN radicals that are complexed with solvent molecules. The lifetimes of the free CN radicals are limited to a few picoseconds following their photolytic production because of geminate recombination to ICN and INC, complexation with CDCl3 molecules, and reaction with acetone. The acetone reaction occurs with a rate coefficient of (8.0 ± 0.5) × 10(10) M(-1) s(-1) and transient vibrational spectra in the C═N and C═O stretching regions reveal that both the nascent HCN and 2-oxopropyl (CH3C(O)CH2) radical products are vibrationally excited. The rate coefficient for the reaction of solvated CN with acetone is 40 times slower than for free CN, with a rate coefficient of (2.0 ± 0.9) × 10(9) M(-1) s(-1) obtained from the rise in the HCN product v1(C═N stretch) IR absorption band. Evidence is also presented for CN complexes with acetone that are more strongly bound than the CN-CDCl3 complexes because of CN interactions with the carbonyl group. The rates of reactions of these more strongly associated radicals are slower still.
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Affiliation(s)
- Greg T Dunning
- School of Chemistry, University of Bristol , Cantock's Close, Bristol BS8 1TS, U.K
| | - Thomas J Preston
- School of Chemistry, University of Bristol , Cantock's Close, Bristol BS8 1TS, U.K
| | - Stuart J Greaves
- School of Engineering and Physical Sciences, Heriot-Watt University , Edinburgh EH14 4AS, U.K
| | - Gregory M Greetham
- Central Laser Facility, Research Complex at Harwell, Science and Technology Facilities Council, Rutherford Appleton Laboratory , Harwell Oxford, Didcot, Oxfordshire OX11 0QX, U.K
| | - Ian P Clark
- Central Laser Facility, Research Complex at Harwell, Science and Technology Facilities Council, Rutherford Appleton Laboratory , Harwell Oxford, Didcot, Oxfordshire OX11 0QX, U.K
| | - Andrew J Orr-Ewing
- School of Chemistry, University of Bristol , Cantock's Close, Bristol BS8 1TS, U.K
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12
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Affiliation(s)
- Andrew J. Orr-Ewing
- School of Chemistry, University of Bristol, Bristol BS8 1TS, United Kingdom;
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13
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Orr-Ewing AJ. Perspective: Bimolecular chemical reaction dynamics in liquids. J Chem Phys 2014; 140:090901. [PMID: 24606343 DOI: 10.1063/1.4866761] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Bimolecular reactions in the gas phase exhibit rich and varied dynamical behaviour, but whether a profound knowledge of the mechanisms of isolated reactive collisions can usefully inform our understanding of reactions in liquid solutions remains an open question. The fluctuating environment in a liquid may significantly alter the motions of the reacting particles and the flow of energy into the reaction products after a transition state has been crossed. Recent experimental and computational studies of exothermic reactions of CN radicals with organic molecules indicate that many features of the gas-phase dynamics are retained in solution. However, observed differences may also provide information on the ways in which a solvent modifies fundamental chemical mechanisms. This perspective examines progress in the use of time-resolved infra-red spectroscopy to study reaction dynamics in liquids, discusses how existing theories can guide the interpretation of experimental data, and suggests future challenges for this field of research.
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Affiliation(s)
- Andrew J Orr-Ewing
- School of Chemistry, University of Bristol, Cantock's Close, Bristol BS8 1TS, United Kingdom
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14
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Zhang Y, Oliver TAA, Das S, Roy A, Ashfold MNR, Bradforth SE. Exploring the Energy Disposal Immediately After Bond-Breaking in Solution: The Wavelength-Dependent Excited State Dissociation Pathways of para-Methylthiophenol. J Phys Chem A 2013; 117:12125-37. [DOI: 10.1021/jp405160n] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Yuyuan Zhang
- Department
of Chemistry, University of Southern California, Los Angeles, California 90089-0482, United States
| | - Thomas A. A. Oliver
- School of Chemistry, Cantocks Close, University of Bristol, Bristol BS8 1TS, U.K
| | - Saptaparna Das
- Department
of Chemistry, University of Southern California, Los Angeles, California 90089-0482, United States
| | - Anirban Roy
- Department
of Chemistry, University of Southern California, Los Angeles, California 90089-0482, United States
| | | | - Stephen E. Bradforth
- Department
of Chemistry, University of Southern California, Los Angeles, California 90089-0482, United States
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15
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Zhang Y, Oliver TAA, Ashfold MNR, Bradforth SE. Contrasting the excited state reaction pathways of phenol and para-methylthiophenol in the gas and liquid phases. Faraday Discuss 2013; 157:141-63; discussion 243-84. [PMID: 23230767 DOI: 10.1039/c2fd20043k] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
To explore how the solvent influences primary aspects of bond breaking, the gas and solution phase photochemistries of phenol and ofpara-methylthiophenol are directly compared using, respectively, H (Rydberg) atom photofragment translation spectroscopy and femtosecond transient absorption spectroscopy. Approaches are demonstrated that allow explicit comparisons of the nascent product energy disposals and dissociation mechanisms in the two phases. It is found, at least for the case of the weakly perturbing cyclohexane environment, that most aspects of the primary reaction dynamics of the isolated molecule are reproduced in solution. Specifically, in the gas phase, both molecules can undergo fast X-H (X = O, S) bond dissociation upon excitation with short wavelengths (193 < lambda(pump) < 216 nm), following population of the dissociative S2 (1 1(pi sigma*)) state. Product electronic branching, vibrational and translational energy disposals are determined. Photolysis of phenol and para-methylthiophenol in solution at 200 nm results in formation of vibrationally excited radicals on a timescale shorter than 200 fs. Excitation of para-methylthiophenol at 267 nm reaches close to the S1 (1 1(pipi*))/S2 (11(pi sigma*)) conical intersection (CI): ultrafast dissociation is observed in both the isolated and solution systems-again indicating direct dissociation on the S2 potential energy surface. Comparing results for this precursor at different excitation energies, the extent of geminate recombination and the derived H-atom ejection lengths in the condensed phase photolyses are in qualitative agreement with the translational energy release measured in the gas phase studies. Conversely, excitation of phenol at 267 nm prepares the system in its S1 state at an energy well below its S1/S2 CI; the slow O-H bond fission inferred in the gas phase experiments is observed directly in the time-resolved studies in cyclohexane solution via the appearance of phenoxyl radical absorption after -1 ns, with only S1 excited state absorption discernible at earlier delay times. The slow O-H bond fission in solution provides additional evidence for a tunnelling dissociation mechanism, where the H atom tunnels beneath the lower diabats of the S2/S1 CI. Finally, the photodissociation of phenol clusters in solution is considered, where evidence is presented that the O-H dissociation coordinate is impeded in H-bonded dimers.
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Affiliation(s)
- Yuyuan Zhang
- Department of Chemistry, University of Southern California, Los Angeles, CA 90089, USA
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16
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Harris SJ, Murdock D, Zhang Y, Oliver TAA, Grubb MP, Orr-Ewing AJ, Greetham GM, Clark IP, Towrie M, Bradforth SE, Ashfold MNR. Comparing molecular photofragmentation dynamics in the gas and liquid phases. Phys Chem Chem Phys 2013; 15:6567-82. [PMID: 23552482 DOI: 10.1039/c3cp50756d] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
This article explores the extent to which insights gleaned from detailed studies of molecular photodissociations in the gas phase (i.e. under isolated molecule conditions) can inform our understanding of the corresponding photofragmentation processes in solution. Systems selected for comparison include a thiophenol (p-methylthiophenol), a thioanisole (p-methylthioanisole) and phenol, in vacuum and in cyclohexane solution. UV excitation in the gas phase results in RX-Y (X = O, S; Y = H, CH3) bond fission in all cases, but over timescales that vary by ~4 orders of magnitude - all of which behaviours can be rationalised on the basis of the relevant bound and dissociative excited state potential energy surfaces (PESs) accessed by UV photoexcitation, and of the conical intersections that facilitate radiationless transfer between these PESs. Time-resolved UV pump-broadband UV/visible probe and/or UV pump-broadband IR probe studies of the corresponding systems in cyclohexane solution reveal additional processes that are unique to the condensed phase. Thus, for example, the data clearly reveal evidence of (i) vibrational relaxation of the photoexcited molecules prior to their dissociation and of the radical fragments formed upon X-Y bond fission, and (ii) geminate recombination of the RX and Y products (leading to reformation of the ground state parent and/or isomeric adducts). Nonetheless, the data also show that, in each case, the characteristics (and the timescale) of the initial bond fission process that occurs under isolated molecule conditions are barely changed by the presence of a weakly interacting solvent like cyclohexane. These condensed phase studies are then extended to an ether analogue of phenol (allyl phenyl ether), wherein UV photo-induced RO-allyl bond fission constitutes the first step of a photo-Claisen rearrangement.
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Affiliation(s)
- Stephanie J Harris
- School of Chemistry, University of Bristol, Cantock's Close, Bristol, BS8 1TS, UK
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17
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O'Donnell BA, Beames JM, Lester MI. Experimental characterization of the CNX2Σ++ Ar and H2potentials via infrared-ultraviolet double resonance spectroscopy. J Chem Phys 2012; 136:234304. [DOI: 10.1063/1.4723696] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
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18
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Rose RA, Greaves SJ, Oliver TAA, Clark IP, Greetham GM, Parker AW, Towrie M, Orr-Ewing AJ. Vibrationally quantum-state-specific dynamics of the reactions of CN radicals with organic molecules in solution. J Chem Phys 2011; 134:244503. [DOI: 10.1063/1.3603966] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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19
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Beames JM, O'Donnell BA, Ting M, Lester MI, Stephenson TA. Experimental characterization of the weakly anisotropic CN X 2Σ+ + Ne potential from IR-UV double resonance studies of the CN-Ne complex. J Chem Phys 2011; 134:184308. [PMID: 21568507 DOI: 10.1063/1.3586810] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
IR-UV double resonance spectroscopy has been used to characterize hindered internal rotor states (n(K) = 0(0), 1(1), and 1(0)) of the CN-Ne complex in its ground electronic state with various degrees of CN stretch (ν(CN)) excitation. Rotationally resolved infrared overtone spectra of the CN-Ne complex exhibit perturbations arising from Coriolis coupling between the closely spaced hindered rotor states (1(1) and 1(0)) with two quanta of CN stretch (ν(CN) = 2). A deperturbation analysis is used to obtain accurate rotational constants and associated average CN center-of-mass to Ne separation distances as well as the coupling strength. The energetic ordering and spacings of the hindered internal rotor states provide a direct reflection of the weakly anisotropic intermolecular potential between CN X (2)Σ(+) and Ne, with only an 8 cm(-1) barrier to CN internal rotation, from which radially averaged anisotropy parameters (V(10) and V(20)) are extracted that are consistent for ν(CN) = 0-3. Complementary ab initio calculation of the CN X (2)Σ(+) + Ne potential using MRCI+Q extrapolated to the complete one-electron basis set limit is compared with the experimentally derived anisotropy by optimizing the radial potential at each angle. Experiment and theory are in excellent accord, both indicating a bent minimum energy configuration and nearly free rotor behavior. Analogous experimental and theoretical studies of the CN-Ne complex upon electronic excitation to the CN B (2)Σ(+) state indicate a slightly more anisotropic potential with a linear CN-Ne minimum energy configuration. The results from these IR-UV double resonance studies are compared with prior electronic spectroscopy and theoretical studies of the CN-Ne system.
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Affiliation(s)
- Joseph M Beames
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6323, USA
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20
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Affiliation(s)
- Stephen Bradforth
- Department of Chemistry, University of Southern California, Los Angeles, CA 90089-0482, USA
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21
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Rivera CA, Winter N, Harper RV, Benjamin I, Bradforth SE. The dynamical role of solvent on the ICN photodissociation reaction: connecting experimental observables directly with molecular dynamics simulations. Phys Chem Chem Phys 2011; 13:8269-83. [DOI: 10.1039/c1cp20252a] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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22
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Oliver TAA, Zhang Y, Ashfold MNR, Bradforth SE. Linking photochemistry in the gas and solution phase: S–H bond fission in p-methylthiophenol following UV photoexcitation. Faraday Discuss 2011; 150:439-58; discussion 505-32. [DOI: 10.1039/c0fd00031k] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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23
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Johnson ML, Benjamin I. Photodissociation of ICN at the Water/Chloroform Interface. J Phys Chem A 2009; 113:7403-11. [DOI: 10.1021/jp900153j] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Mindy L. Johnson
- Department of Chemistry and Biochemistry, University of California, Santa Cruz, California 95064
| | - Ilan Benjamin
- Department of Chemistry and Biochemistry, University of California, Santa Cruz, California 95064
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24
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Crowther AC, Carrier SL, Preston TJ, Crim FF. Time-Resolved Studies of the Reactions of CN Radical Complexes with Alkanes, Alcohols, and Chloroalkanes. J Phys Chem A 2009; 113:3758-64. [DOI: 10.1021/jp8084099] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Andrew C. Crowther
- Department of Chemistry, University of Wisconsin−Madison, Madison, Wisconsin 53706
| | - Stacey L. Carrier
- Department of Chemistry, University of Wisconsin−Madison, Madison, Wisconsin 53706
| | - Thomas J. Preston
- Department of Chemistry, University of Wisconsin−Madison, Madison, Wisconsin 53706
| | - F. Fleming Crim
- Department of Chemistry, University of Wisconsin−Madison, Madison, Wisconsin 53706
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25
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Crowther AC, Carrier SL, Preston TJ, Crim FF. Time-Resolved Studies of CN Radical Reactions and the Role of Complexes in Solution. J Phys Chem A 2008; 112:12081-9. [DOI: 10.1021/jp8064079] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Andrew C. Crowther
- Department of Chemistry, University of Wisconsin − Madison, Madison, Wisconsin 53706
| | - Stacey L. Carrier
- Department of Chemistry, University of Wisconsin − Madison, Madison, Wisconsin 53706
| | - Thomas J. Preston
- Department of Chemistry, University of Wisconsin − Madison, Madison, Wisconsin 53706
| | - F. Fleming Crim
- Department of Chemistry, University of Wisconsin − Madison, Madison, Wisconsin 53706
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26
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Petersen C, Thøgersen J, Knak Jensen S, Keiding SR, Sassi P. Solvent response to solute photo-dissociation. Phys Chem Chem Phys 2008; 10:990-5. [DOI: 10.1039/b711466d] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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27
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Tao G, Stratt RM. The molecular origins of nonlinear response in solute energy relaxation: The example of high-energy rotational relaxation. J Chem Phys 2006; 125:114501. [PMID: 16999484 DOI: 10.1063/1.2336780] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
A key step in solution-phase chemical reactions is often the removal of excess internal energy from the product. Yet, the way one typically studies this process is to follow the relaxation of a solute that has been excited into some distribution of excited states quite different from that produced by any reaction of interest. That the effects of these different excitations can frequently be ignored is a consequence of the near universality of linear-response behavior, the idea that relaxation dynamics is determined by the solvent fluctuations (which may not be all that different for different kinds of solute excitation). Nonetheless, there are some clear examples of linear-response breakdowns seen in solute relaxation, including a recent theoretical and experimental study of rapidly rotating diatomics in liquids. In this paper we use this rotational relaxation example to carry out a theoretical exploration of the conditions that lead to linear-response failure. Some features common to all of the linear-response breakdowns studied to date, including our example, are that the initial solute preparation is far from equilibrium, that the subsequent relaxation promotes a significant rearrangement of the liquid structure, and that the nonequilibrium response is nonstationary. However, we show that none of these phenomena is enough to guarantee a nonlinear response. One also needs a sufficient separation between the solute time scale and that of the solvent geometry evolution. We illustrate these points by demonstrating precisely how our relaxation rate is tied to our liquid-structural evolution, how we can quantitatively account for the initial nonstationarity of our effective rotational friction, and how one can tune our rotational relaxation into and out of linear response.
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Affiliation(s)
- Guohua Tao
- Department of Chemistry, Brown University, Providence, Rhode Island 02912, USA
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28
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Moskun AC, Bradforth SE, Thøgersen J, Keiding S. Absence of a Signature of Aqueous I(2P1/2) after 200-nm Photodetachment of I-(aq). J Phys Chem A 2006; 110:10947-55. [PMID: 16986827 DOI: 10.1021/jp053992+] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Ultrafast pump-broadband probe spectroscopy was used to study the transient photoproducts following 200-nm photodetachment of I(-)(aq). Resonant detachment at 200 nm in the second charge-transfer-to-solvent (CTTS) band of I(-)(aq) is expected to produce an electron and iodine in its spin-orbit excited state, I*((2)P(1/2)). The transients in solution following photodetachment were probed from 200 to 620 nm. Along with strong absorption in the visible region due to solvated electrons and a strong bleach of the I(-)(aq) ground-state absorption, a weaker transient absorption near 260 nm was observed that is consistent with a previously assigned ground-state I((2)P(3/2)) charge-transfer band. However, no evidence was found for an equivalent I*(aq) charge-transfer absorption, and I((2)P(3/2)) was produced within the instrument response. This suggests either that I* is electronically relaxed in less than 300 fs or that excitation in the second CTTS band does not in fact lead to I*. The consequences for previous experimental work where I*(aq) production has been postulated, as well as for halogen electron ejection mechanisms, are discussed. In addition, the broad spectral coverage of this study reveals in the bleach recovery the rapid cooling of the solvent surrounding the re-formed iodide after geminate recombination of the iodine with the solvated electron.
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Affiliation(s)
- Amy C Moskun
- Department of Chemistry, University of Southern California, Los Angeles, California 90089, USA
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29
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Abstract
▪ Abstract Modern ultrafast spectroscopic techniques provide new opportunities to study chemical reaction dynamics in liquids and hold the possibility of obtaining much of the same detailed information available in gases. Vibrational energy transfer studies are the most advanced of the investigations and demonstrate that it is possible to observe state-specific pathways of energy flow within a vibrationally excited molecule (intramolecular vibrational relaxation) and into the surrounding solvent molecules (intermolecular energy transfer). Energy transfer in liquids and gases share many common aspects, but the presence of the solvent also alters the relaxation in both obvious and subtle ways. Photodissociation is amenable to similarly detailed study in liquids, and there are informative new measurements. Bimolecular reactions have received the least attention in state-resolved measurements in liquids, but the means to carry them much further now exist. Studying photodissociation and bimolecular reaction of molecules prepared with initial vibrational excitation in liquids is a realistic, but challenging, goal.
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Affiliation(s)
- Christopher G Elles
- Department of Chemistry, University of Southern California, Los Angeles, California 90089, USA.
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30
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Moskun AC, Jailaubekov AE, Bradforth SE, Tao G, Stratt RM. Rotational Coherence and a Sudden Breakdown in Linear Response Seen in Room-Temperature Liquids. Science 2006; 311:1907-11. [PMID: 16574863 DOI: 10.1126/science.1123738] [Citation(s) in RCA: 87] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Highly energized molecules normally are rapidly equilibrated by a solvent; this finding is central to the conventional (linear-response) view of how chemical reactions occur in solution. However, when a reaction initiated by 33-femtosecond deep ultraviolet laser pulses is used to eject highly rotationally excited diatomic molecules into alcohols and water, rotational coherence persists for many rotational periods despite the solvent. Molecular dynamics simulations trace this slow development of molecular-scale friction to a clearly identifiable molecular event: an abrupt liquid-structure change triggered by the rapid rotation. This example shows that molecular relaxation can sometimes switch from linear to nonlinear response.
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Affiliation(s)
- Amy C Moskun
- Department of Chemistry, University of Southern California, Los Angeles, CA 90089, USA
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31
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Pieniazek PA, Bradforth SE, Krylov AI. Spectroscopy of the Cyano Radical in an Aqueous Environment. J Phys Chem A 2006; 110:4854-65. [PMID: 16599455 DOI: 10.1021/jp0545952] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The effect of bulk water on the B (2)Sigma(+) <-- X (2)Sigma(+) and A (2)Pi <-- X (2)Sigma(+) electronic transitions of the cyano radical is investigated. First, the cyano radical-water dimer is characterized to understand the nature of the interactions and parametrize molecular mechanics (MM) potentials. The carbon atom, which hosts the unpaired electron, is found to have a Lennard-Jones radius smaller than typical force fields values. Classical molecular dynamics (MD) is then used to sample water configurations around the radical, employing two sets of MM parameters for the cyano radical and water. Subsequently, vertical excitation energies are calculated using time-dependent density functional theory (TD-DFT) and equation-of-motion coupled-cluster with single and double substitutions (EOM-CCSD). The effect of water is modeled by point charges used in the MD simulations. It is found that both bands blue-shift with respect to their gas phase position; the magnitude of the shift is only weakly dependent on the method and the MM parameter set used. The calculated shifts are analyzed in terms of the solute-solvent interactions in the ground and excited states. Significant contributions come from valence repulsion and electrostatics. Consequences for experiments on ICN photodissociation in water are discussed.
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Affiliation(s)
- Piotr A Pieniazek
- Department of Chemistry, University of Southern California, Los Angeles, 90089-0482, USA
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32
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Elles CG, Cox MJ, Barnes GL, Crim FF. Recombination and Reaction Dynamics Following Photodissociation of CH3OCl in Solution. J Phys Chem A 2004. [DOI: 10.1021/jp046627b] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Christopher G. Elles
- Department of Chemistry, University of Wisconsin − Madison, Madison, Wisconsin 53706
| | - M. Jocelyn Cox
- Department of Chemistry, University of Wisconsin − Madison, Madison, Wisconsin 53706
| | - George L. Barnes
- Department of Chemistry, University of Wisconsin − Madison, Madison, Wisconsin 53706
| | - F. Fleming Crim
- Department of Chemistry, University of Wisconsin − Madison, Madison, Wisconsin 53706
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33
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Winter N, Benjamin I. Photodissociation of ICN at the liquid/vapor interface of water. J Chem Phys 2004; 121:2253-63. [PMID: 15260780 DOI: 10.1063/1.1765093] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The photodissociation of ICN adsorbed at the liquid/vapor interface of water is studied using classical molecular dynamics with nonadiabatic surface hopping. The cage escape, geminate recombination to form ICN and INC and the subsequent vibrational relaxation of these two molecules (on their ground electronic states) is compared with the same process in bulk water and with previous photodissociation studies at liquid interfaces. We find that the reduced surface density and weaker solvent-solute interactions give rise to reduced rate of nonadiabatic transitions and that the probability for cage escape at the interface is significantly enhanced due to the possibility that one or both of the photodissociation fragments desorb into the gas phase. The overall desorption probability varies from 75% to 92% for ICN initially located just below the Gibbs surface (50% bulk density) to ICN located just above the Gibbs surface, respectively. The corresponding geminate recombination probabilities are 18% and 9%, respectively. The vibrational relaxation rate of the recombined ICN is slower than in the bulk by a factor of 2.3.
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Affiliation(s)
- Nicole Winter
- Department of Chemistry, University of California, Santa Cruz 95064, USA
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34
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Madsen D, Larsen J, Jensen SK, Keiding SR, Thøgersen J. The Primary Photodynamics of Aqueous Nitrate: Formation of Peroxynitrite. J Am Chem Soc 2003; 125:15571-6. [PMID: 14664604 DOI: 10.1021/ja030135f] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
We have examined the photochemical reactions occurring after irradiation at 200 nm of the aqueous nitrate ion, NO3(-)(aq). Using femtosecond transient absorption spectroscopy over the range 194-388 nm, we have characterized the formation and subsequent relaxation of the primary photoproducts of nitrate photolysis. The dominant photoproduct is the cis-isomer of peroxynitrite, which accounts for 48% of the excited state molecules initially produced. A slightly smaller fraction, 44%, of the excited molecules return to the electronic ground state of NO3(-) and relax to the vibrational ground state in 2 ps. The remaining 8% of the molecules initially excited react via the *NO + *O2(-) or the NO- + O2 dissociation channels. Formation of NO2(-) and *NO2 is not observed, suggesting that the previous observations of these species in steady-state photolysis are caused by reactions occurring on a longer time scale.
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Affiliation(s)
- Dorte Madsen
- Department of Chemistry, University of Aarhus, Langelandsgade 140, DK-8000, Aarhus, Denmark
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35
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Moskun AC, Bradforth SE. Photodissociation of ICN in polar solvents: Evidence for long lived rotational excitation in room temperature liquids. J Chem Phys 2003. [DOI: 10.1063/1.1591726] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
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36
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Winter N, Chorny I, Vieceli J, Benjamin I. Molecular dynamics study of the photodissociation and photoisomerization of ICN in water. J Chem Phys 2003. [DOI: 10.1063/1.1585019] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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37
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Kim NJ, Paik DH, Zewail AH. Femtosecond dynamics of solvated oxygen anions. II. Nature of dissociation and caging in finite-sized clusters. J Chem Phys 2003. [DOI: 10.1063/1.1561434] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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38
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Shi Q, Geva E. Vibrational energy relaxation rate constants from linear response theory. J Chem Phys 2003. [DOI: 10.1063/1.1562611] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
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39
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Poulsen JA, Nyman G, Rossky PJ. A second-order Kubo response theory-centroid approach to vibrational energy relaxation for single-mode excitations. J Chem Phys 2002. [DOI: 10.1063/1.1522376] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
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