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Li S, Jochim B, Jackson JE, Dantus M. Femtosecond dynamics and coherence of ionic retro-Diels-Alder reactions. J Chem Phys 2021; 155:044303. [PMID: 34340396 DOI: 10.1063/5.0048380] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Ultrafast tunnel ionization enables femtosecond time-resolved dynamic measurements of the retro-Diels-Alder reactions of positively charged cyclohexene, norbornene, and dicyclopentadiene. Unlike the reaction times of 500-600 ps that are observed following UV excitation of neutral species, on the ionic potential energy surfaces, these reactions occur on a single picosecond timescale and, in some cases, exhibit vibrational coherence. In the case of norbornene, a 270 cm-1 vibrational mode is found to modulate the retro-Diels-Alder reaction.
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Affiliation(s)
- Shuai Li
- Department of Chemistry, Michigan State University, East Lansing, Michigan 48824, USA
| | - Bethany Jochim
- Department of Chemistry, Michigan State University, East Lansing, Michigan 48824, USA
| | - James E Jackson
- Department of Chemistry, Michigan State University, East Lansing, Michigan 48824, USA
| | - Marcos Dantus
- Department of Chemistry, Michigan State University, East Lansing, Michigan 48824, USA
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2
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López J, de la Cruz FN, Flores-Conde MI, Flores-Álamo M, Delgado F, Tamariz J, Vázquez MA. Regioselective Multicomponent Synthesis of 2,4,6-Trisubstituted Phenols from Fischer Alkynyl Carbene Complexes. European J Org Chem 2016. [DOI: 10.1002/ejoc.201501211] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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3
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Krčmář J, Gelin MF, Domcke W. Simulation of femtosecond two-dimensional electronic spectra of conical intersections. J Chem Phys 2015; 143:074308. [PMID: 26298135 DOI: 10.1063/1.4928685] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
We have simulated femtosecond two-dimensional (2D) electronic spectra for an excited-state conical intersection using the wave-function version of the equation-of-motion phase-matching approach. We show that 2D spectra at fixed values of the waiting time provide information on the structure of the vibronic eigenstates of the conical intersection, while the evolution of the spectra with the waiting time reveals predominantly ground-state wave-packet dynamics. The results show that 2D spectra of conical intersection systems differ significantly from those obtained for chromophores with well separated excited-state potential-energy surfaces. The spectral signatures which can be attributed to conical intersections are discussed.
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Affiliation(s)
- Jindřich Krčmář
- Department of Chemistry, Technische Universität München, D-85747 Garching, Germany
| | - Maxim F Gelin
- Department of Chemistry, Technische Universität München, D-85747 Garching, Germany
| | - Wolfgang Domcke
- Department of Chemistry, Technische Universität München, D-85747 Garching, Germany
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Staedter D, Thiré N, Polizzi L, Mairesse Y, Mayer P, Blanchet V. Femtosecond time-resolved electronic relaxation dynamics in tetrathiafulvalene. J Chem Phys 2015; 142:194306. [PMID: 26001460 DOI: 10.1063/1.4921319] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
In the present paper, the ultrafast electronic relaxation of tetrathiafulvalene (TTF) initiated around 4 eV is studied by femtosecond time-resolved velocity-map imaging. The goal is to investigate the broad double structure observed in the absorption spectrum at this energy. By monitoring the transients of the parent cation and its fragments and by varying the pump and the probe wavelengths, two internal conversions and intramolecular vibrational relaxation are detected both on the order of a few hundred of femtoseconds. Photoelectron images permit the assignment of a dark electronic state involved in the relaxation. In addition, the formation of the dimer of TTF has been observed.
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Affiliation(s)
- D Staedter
- Laboratoire de Collisions, Agrégats et Réactivité, IRSAMC, Université de Toulouse-CNRS, 31062 Toulouse, France
| | - N Thiré
- Laboratoire de Collisions, Agrégats et Réactivité, IRSAMC, Université de Toulouse-CNRS, 31062 Toulouse, France
| | - L Polizzi
- Laboratoire de Collisions, Agrégats et Réactivité, IRSAMC, Université de Toulouse-CNRS, 31062 Toulouse, France
| | - Y Mairesse
- Centre des Laser Intenses et Applications, Université de Bordeaux-CNRS, 33405 Talence, France
| | - P Mayer
- Chemistry Department, University of Ottawa, Ottawa, Ontario K1N 6N5, Canada
| | - V Blanchet
- Laboratoire de Collisions, Agrégats et Réactivité, IRSAMC, Université de Toulouse-CNRS, 31062 Toulouse, France
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Blancafort L. Photochemistry and photophysics at extended seams of conical intersection. Chemphyschem 2014; 15:3166-81. [PMID: 25157686 DOI: 10.1002/cphc.201402359] [Citation(s) in RCA: 65] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2014] [Indexed: 11/07/2022]
Abstract
The role of extended seams of conical intersection in excited-state mechanisms is reviewed. Seams are crossings of the potential energy surface in many dimensions where the decay from the excited to the ground state can occur, and the extended seam is composed of different segments lying along a reaction coordinate. Every segment is associated with a different primary photoproduct, which gives rise to competing pathways. This idea is first illustrated for fulvene and ethylene, and then it is used to explain more complex cases such as the dependence of the isomerisation of retinal chromophore isomers on the protein environment, the dependence of the efficiency of the azobenzene photochemical switch on the wavelength of irradiation and the direction of the isomerisation, and the coexistence of different mechanisms in the photo-induced Wolff rearrangement of diazonaphthoquinone. The role of extended seams in the photophysics of the DNA nucleobases and the relationship between two-state seams and three-state crossings is also discussed. As an outlook, the design of optical control strategies based on the passage of the excited molecule through the seam is considered, and it is shown how the excited-state lifetime of fulvene can be modulated by shaping the energy of the seam.
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Affiliation(s)
- Lluís Blancafort
- Institut de Química Computacional i Catàlisi and Departament de Química, Universitat de Girona, Campus de Montilivi, 17071 Girona (Spain).
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Schalk O, Boguslavskiy AE, Stolow A. Two-Photon Excited State Dynamics of Dark Valence, Rydberg, and Superexcited States in 1,3-Butadiene. J Phys Chem Lett 2014; 5:560-565. [PMID: 26276609 DOI: 10.1021/jz402725u] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Two-photon absorption in systems with parity permits access to states that cannot be prepared by one-photon absorption. Here we present the first time-resolved photoelectron spectroscopy study using this technique, applied to 1,3-butadiene, in which we investigated the dynamics of its dark valence, Rydberg, and superexcited states. The dark valence state dynamics are accessed via the Rydberg manifold, excited by two photons of 400 nm. We find that the 'dark' 2(1)Ag state populated in this manner has a much longer lifetime than when accesses via the 1(1)Bu 'bright' valence state when populated by one photon of 200 nm. In addition, we compared the dynamics of the 3sπ- and 3dπ-Rydberg states. These Rydberg states relax to the valence manifold on a subpicosecond time scale, with the 3sπ-Rydberg state decay rate being larger due to a stronger valence-Rydberg mixing. Finally, we investigated superexcited valence states that fragment or autoionize within 200 fs, likely without involving Rydberg states.
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Affiliation(s)
- Oliver Schalk
- †Stockholm University, AlbaNova University Center, Roslagstullsbacken 21, SE-106 91 Stockholm, Sweden
- ‡National Research Council of Canada, 100 Sussex Drive, Ottawa, Ontario K1A 0R6, Canada
| | - Andrey E Boguslavskiy
- ‡National Research Council of Canada, 100 Sussex Drive, Ottawa, Ontario K1A 0R6, Canada
| | - Albert Stolow
- ‡National Research Council of Canada, 100 Sussex Drive, Ottawa, Ontario K1A 0R6, Canada
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West BA, Molesky BP, Giokas PG, Moran AM. Uncovering molecular relaxation processes with nonlinear spectroscopies in the deep UV. Chem Phys 2013. [DOI: 10.1016/j.chemphys.2013.06.027] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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Goswami T, Das DK, Goswami D. Controlling the femtosecond laser-driven transformation of dicyclopentadiene into cyclopentadiene. Chem Phys Lett 2013; 558:1-7. [PMID: 24098059 PMCID: PMC3790071 DOI: 10.1016/j.cplett.2012.10.054] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
Dynamics of the chemical transformation of dicyclopentadiene into cyclopentadiene in a supersonic molecular beam is elucidated using femtosecond time-resolved degenerate pump-probe mass spectrometry. Control of this ultrafast chemical reaction is achieved by using linearly chirped frequency modulated pulses. We show that negatively chirped femtosecond laser pulses enhance the cyclopentadiene photo-product yield by an order of magnitude as compared to that of the unmodulated or the positively chirped pulses. This demonstrates that the phase structure of femtosecond laser pulse plays an important role in determining the outcome of a chemical reaction.
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Affiliation(s)
| | - Dipak K. Das
- Department of Chemistry, Indian Institute of Technology, Kanpur 208016, India
| | - Debabrata Goswami
- Department of Chemistry, Indian Institute of Technology, Kanpur 208016, India
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Wu G, Boguslavskiy AE, Schalk O, Schuurman MS, Stolow A. Ultrafast non-adiabatic dynamics of methyl substituted ethylenes: The π3s Rydberg state. J Chem Phys 2011; 135:164309. [DOI: 10.1063/1.3652966] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
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Kosma K, Trushin SA, Fuss W, Schmid WE. Ultrafast Dynamics and Coherent Oscillations in Ethylene and Ethylene-d4 Excited at 162 nm. J Phys Chem A 2008; 112:7514-29. [DOI: 10.1021/jp803548c] [Citation(s) in RCA: 83] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Affiliation(s)
- K. Kosma
- Max-Planck-Institut für Quantenoptik, D-85741 Garching, Germany
| | - S. A. Trushin
- Max-Planck-Institut für Quantenoptik, D-85741 Garching, Germany
| | - W. Fuss
- Max-Planck-Institut für Quantenoptik, D-85741 Garching, Germany
| | - W. E. Schmid
- Max-Planck-Institut für Quantenoptik, D-85741 Garching, Germany
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Schalk O, Unterreiner AN. Ultrafast Relaxation Dynamics of Perchlorinated Cycloheptatriene in Solution. J Phys Chem A 2007; 111:3231-40. [PMID: 17428037 DOI: 10.1021/jp066193f] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The photochemistry of perchlorinated cycloheptatriene (CHTCl(8)) has been studied by means of ultrafast pump-probe, transient anisotropy and continuous UV-irradiation experiments in various solvents as well as by DFT calculations. After UV-excitation to the 1A' '-state, two competing reactions occur--a [1,7]-sigmatropic chlorine migration via two ultrafast internal conversions and a [4,5]-electrocyclization forming octachlorobicylo[3.2.0]hepta-[2,6]-diene. The first reaction has been studied by excitation with a 263 nm femtosecond-laser pulse. Pump-probe experiments reveal a first, solvent-independent time constant, tau1(CHTCl(8)) = 140 fs, that can be associated with the electronic relaxation of the 2A'-1A' ' transition, while a second one, tau2(CHTCl(8)), ranges from 0.9 to 1.8 ps depending on the polarity of the solvent. This finding is consistent with a [1,7]-chlorine migration during the 1A'-2A' transition where the migrating chlorine atom is partly negatively charged. The charge separation has also been confirmed by DFT calculations. Transient anisotropy measurements result in a time zero value of r(0) = 0.35 after deconvolution and a decay constant of tau1(a) = 120 fs, which can be explained by vibrational motions of CHTCl(8) in the electronically excited states, 1A' ' and 2A'. After continuous UV-irradiation of CHTCl(8), octachlorobicylo[3.2.0]hepta-[2,6]-diene is primarily formed with a solvent-dependent yield. From these investigations, we suggest a relaxation mechanism for CHTCl(8) after photoexcitation that is comparable to cycloheptatriene.
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Affiliation(s)
- O Schalk
- Institut für Physikalische Chemie, Kaiserstr. 12, 76128 Karlsruhe Universität Karlsruhe (TH), Germany
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Wilsey S, Houk KN. "H/Vinyl" and "Alkyl/Vinyl" conical intersections leading to carbene formation from the excited states of cyclohexene and norbornene. J Am Chem Soc 2002; 124:11182-90. [PMID: 12224966 DOI: 10.1021/ja012565g] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The photochemical [1,2]-shifts leading to carbene intermediates from cyclohexene and norbornene have been studied using CASSCF calculations and a 6-31G* basis set. In each case, a S(1)/S(0) conical intersection hyperline was identified that extends from the region of the reactant excited state to the carbene product. It is traditionally thought that the Rydberg R(pi,3s) state is responsible for carbene formation on photolysis of cyclic alkenes, but these new results indicate an efficient mechanism for carbene formation following excitation to the (1)(pipi*) state. This pathway is essentially barrierless and involves internal conversion to the ground-state surface via conical intersections between the excited zwitterionic valence state and the ground-state surface, similar to those responsible for cis-trans isomerization in ethene and other acyclic alkenes. These results are in excellent agreement with recent experimental data obtained using femtosecond spectroscopy.
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Affiliation(s)
- Sarah Wilsey
- Contribution from the Department of Chemistry, King's College London, Strand, London WC2R 2LS, U.K.
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Fuss W, Pushpa KK, Schmid WE, Trushin SA. Ultrafast [2 + 2]-cycloaddition in norbornadiene. Photochem Photobiol Sci 2002; 1:60-6. [PMID: 12659150 DOI: 10.1039/b107442c] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Excitation of norbornadiene (bicyclo[2.2.1]hepta-2,5-diene) at 200 nm populates two states in parallel, the second pi(pi*) state and a Rydberg state. We monitored both populations by transient nonresonant ionization. From the pi(pi*) state the molecule relaxes in consecutive steps with time constants 5, 31 and 55 fs down to the ground-state surface, whereas the Rydberg population merges to the other path on the pi(pi*) surface within 420 fs. The relaxation steps are discussed in terms of conical intersections (CoIns) between different surfaces Information on them is inferred from known spectroscopy and, for the last CoIn, from published calculations on Dewar benzene-->prismane conversion and on ethylene photodimerization for which norbornadiene with its two nonconjugated double bonds is a model. The calculation predicts symmetry breaking for this CoIn, the two ethylenes forming a rhombus Although this distortion is hindered in norbornadiene by ring strain, this CoIn seems easily accessible as indicated by the short time (<55 fs) found for passing through it.
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Affiliation(s)
- Werner Fuss
- Max-Planck-Institut für Quantenoptik, D-85741, Garching, Germany
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