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Heald LF, Gosman RS, Rotteger CH, Jarman CK, Sayres SG. Nonadiabatic Photodissociation and Dehydrogenation Dynamics of n-Butyl Bromide Following p-Rydberg Excitation. J Phys Chem Lett 2023:6278-6285. [PMID: 37399455 DOI: 10.1021/acs.jpclett.3c01438] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/05/2023]
Abstract
Femtosecond time-resolved mass spectrometry, correlation mapping, and density functional theory calculations are employed to reveal the mechanism of C═C and C≡C formation (and related H2 production) following excitation to the p-Rydberg states of n-butyl bromide. Ultrafast pump-probe mass spectrometry shows that nonadiabatic relaxation operates as a multistep process reaching an intermediate state within ∼500 fs followed by relaxation to a final state within 10 ps of photoexcitation. Absorption of three ultraviolet photons accesses the dense p-Rydberg state manifold, which is further excited by the probe beam for C─C bond dissociation and dehydrogenation reactions. Rapid internal conversion deactivates the dehydrogenation pathways, while activating carbon backbone dissociation pathways. Thus, unsaturated carbon fragments decay with the lifetime of p-Rydberg (∼500 fs), matching the growth recorded in saturated hydrocarbon fragments. The saturated hydrocarbon signals subsequently decay on the picosecond time scale as the molecule relaxes below the Rydberg states and into halogen release channels.
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Affiliation(s)
- Lauren F Heald
- School of Molecular Sciences, Arizona State University, Tempe, Arizona 85287, United States
- Biodesign Center for Applied Structural Discovery, Arizona State University, Tempe, Arizona 85287, United States
| | - Robert S Gosman
- School of Molecular Sciences, Arizona State University, Tempe, Arizona 85287, United States
- Biodesign Center for Applied Structural Discovery, Arizona State University, Tempe, Arizona 85287, United States
| | - Chase H Rotteger
- School of Molecular Sciences, Arizona State University, Tempe, Arizona 85287, United States
- Biodesign Center for Applied Structural Discovery, Arizona State University, Tempe, Arizona 85287, United States
| | - Carter K Jarman
- School of Molecular Sciences, Arizona State University, Tempe, Arizona 85287, United States
- Biodesign Center for Applied Structural Discovery, Arizona State University, Tempe, Arizona 85287, United States
| | - Scott G Sayres
- School of Molecular Sciences, Arizona State University, Tempe, Arizona 85287, United States
- Biodesign Center for Applied Structural Discovery, Arizona State University, Tempe, Arizona 85287, United States
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Heald LF, Loftus CL, Gosman RS, Sayres SG. Ion-Pair Formation in n-Butyl Bromide through 5p Ryberg State Predissociation. J Phys Chem A 2022; 126:9651-9657. [PMID: 36528811 DOI: 10.1021/acs.jpca.2c06777] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
The ultrafast photodynamics of n-butyl bromide are explored with femtosecond time-resolved mass spectrometry. Absorption of two UV (400 nm) pump photons induces the direct dissociation of the C-Br bond from the A state within 160 fs. Absorption of three UV pump photons excites the molecule into the 5p Rydberg state which undergoes several relaxation pathways including to the ion-pair state. Relaxation to the ion-pair state is tracked through the transient of the C4H9+ fragment and suggests an E state lifetime of 10.8 ± 0.5 ps, in close agreement with the tunneling time of smaller molecules. Predissociation from the 5p Rydberg states leads to the β-elimination of H-Br and formation of C4H8+ within 3.0 ± 0.25 ps. A portion of the excited parent molecule avoids the ion-pair formation and instead relaxes through the Rydberg excited state manifold into the D state within 30.2 ± 0.21 ps.
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Affiliation(s)
- Lauren F Heald
- School of Molecular Sciences, Arizona State University, Tempe, Arizona85287, United States.,Biodesign Center for Applied Structural Discovery, Arizona State University, Tempe, Arizona85287, United States
| | - Colleen L Loftus
- School of Molecular Sciences, Arizona State University, Tempe, Arizona85287, United States.,Biodesign Center for Applied Structural Discovery, Arizona State University, Tempe, Arizona85287, United States
| | - Robert S Gosman
- School of Molecular Sciences, Arizona State University, Tempe, Arizona85287, United States.,Biodesign Center for Applied Structural Discovery, Arizona State University, Tempe, Arizona85287, United States
| | - Scott G Sayres
- School of Molecular Sciences, Arizona State University, Tempe, Arizona85287, United States.,Biodesign Center for Applied Structural Discovery, Arizona State University, Tempe, Arizona85287, United States
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Solling TI. Nonstatistical Photoinduced Processes in Gaseous Organic Molecules. ACS OMEGA 2021; 6:29325-29344. [PMID: 34778606 PMCID: PMC8581993 DOI: 10.1021/acsomega.1c04035] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/28/2021] [Indexed: 05/26/2023]
Abstract
Processes that proceed in femtoseconds are usually referred to as being ultrafast, and they are investigated in experiments that involve laser pulses with femtosecond duration in so-called pump probe schemes, where a light pulse triggers a molecular process and a second light pulse interrogates the temporal evolution of the molecular population. The focus of this review is on the reactivity patterns that arise when energy is not equally distributed on all the available degrees of freedom as a consequence of the very short time scale in play and on how the localization of internal energy in a specific mode can be thought of as directing a process toward (or away from) a certain outcome. The nonstatistical aspects are illustrated with examples from photophysics and photochemistry for a range of organic molecules. The processes are initiated by a variety of nuclear motions that are all governed by the energy gradients in the Franck-Condon region. Essentially, the molecules will start to adapt to the new electronic environment on the excited state to eventually reach the equilibrium structure. It is this structural change that is enabling an ultrafast electronic transition in cases where the nuclear motion leads to a transition point with significant coupling between to electronic states and to ultrafast reaction if there is a coupling to a reactive mode at the transition point between the involved states. With the knowledge of the relation between electronic excitation and equilibrium structure, it is possible to predict how the nuclei move after excitation and often whether an ultrafast (and inherently nonstatistical) electronic transition or even a bond breakage will take place. In addition to the understanding of how nonstatistical photoinduced processes proceed from a given excited state, it has been found that randomization of the energy does not even always take place when the molecule takes part in processes that are normally considered statistical, such as for example nonradiative transitions between excited states. This means that energy can be localized in a specific degree of freedom on a state other than the one that is initially prepared. This is a finding that could kickoff the ultimate dream in applied photochemistry; namely light excitation that leads to the rupture of a specific bond.
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Affiliation(s)
- Theis I. Solling
- Center for Integrative Petroleum
Research, King Fahd University of Petroleum
& Minerals, Dhahran, 31261, Saudi Arabia
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Sølling TI, Møller KB. Perspective: Preservation of coherence in photophysical processes. STRUCTURAL DYNAMICS (MELVILLE, N.Y.) 2018; 5:060901. [PMID: 30868079 PMCID: PMC6404954 DOI: 10.1063/1.5079265] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/30/2018] [Accepted: 12/05/2018] [Indexed: 06/09/2023]
Abstract
Coherence is one of the most important phenomena in ultrafast sciences. We give our perspective on the terminology, observation, and preservation of coherence in photophysical processes with some glimpses to the past and some looking-head to what may pave the way for scaling one of the last bastions in ultrafast science, namely, that of mode specific chemistry where it will be possible to break any specific bond by tailoring the pulse, an accomplishment that obviously would be the dream of any chemist.
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Affiliation(s)
- Theis I Sølling
- Center for Integrative Petroleum Research, College of Petroleum and Geosciences, King Fahad University of Petroleum and Minerals, Dhahran 31261, Saudi Arabia
| | - Klaus B Møller
- Department of Chemistry, Technical University of Denmark, Kemitorvet 207, 2800 Kgs. Lyngby, Denmark
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Sølling TI, Kuhlman TS, Stephansen AB, Klein LB, Møller KB. The Non-Ergodic Nature of Internal Conversion. Chemphyschem 2013; 15:249-59. [DOI: 10.1002/cphc.201300926] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2013] [Revised: 11/22/2013] [Indexed: 11/08/2022]
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Minitti MP, Zhang Y, Rosenberg M, Brogaard RY, Deb S, Sølling TI, Weber PM. Far-UV photochemical bond cleavage of n-amyl nitrite: bypassing a repulsive surface. J Phys Chem A 2012; 116:810-9. [PMID: 22175717 DOI: 10.1021/jp209727g] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We have investigated the deep-UV photoinduced, homolytic bond cleavage of amyl nitrite to form NO and pentoxy radicals. One-color multiphoton ionization with ultrashort laser pulses through the S(2) state resonance gives rise to photoelectron spectra that reflect ionization from the S(1) state. Time-resolved pump-probe photoionization measurements show that upon excitation at 207 nm, the generation of NO in the v = 2 state is delayed, with a rise time of 283 (16) fs. The time-resolved mass spectrum shows the NO to be expelled with a kinetic energy of 1.0 eV, which is consistent with dissociation on the S(1) state potential energy surface. Combined, these observations show that the first step of the dissociation reaction involves an internal conversion from the S(2) to the S(1) state, which is followed by the ejection of the NO radical on the predissociative S(1) state potential energy surface.
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Affiliation(s)
- Michael P Minitti
- SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
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Brogaard RY, Møller KB, Sølling TI. Real-Time Probing of Structural Dynamics by Interaction between Chromophores. J Phys Chem A 2011; 115:12120-5. [DOI: 10.1021/jp2072588] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
| | - Klaus B. Møller
- Department of Chemistry, Building 207, Technical University of Denmark, Kgs. Lyngby, Denmark
| | - Theis I. Sølling
- Department of Chemistry, University of Copenhagen, Copenhagen, Denmark
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Brogaard RY, Boguslavskiy AE, Schalk O, Enright GD, Hopf H, Raev VA, Jones PG, Thomsen DL, Sølling TI, Stolow A. Pseudo-Bimolecular [2+2] Cycloaddition Studied by Time-Resolved Photoelectron Spectroscopy. Chemistry 2011; 17:3922-31. [DOI: 10.1002/chem.201002928] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2010] [Indexed: 11/07/2022]
Affiliation(s)
- Rasmus Y Brogaard
- Steacie Institute for Molecular Sciences, National Research Council (Canada), Ottawa, ON, Canada
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Brogaard RY, Møller KB, Sølling TI. Wave Packet Simulation of Nonadiabatic Dynamics in Highly Excited 1,3-Dibromopropane. J Phys Chem A 2008; 112:10481-6. [DOI: 10.1021/jp805273w] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Affiliation(s)
- Rasmus Y. Brogaard
- Center for Molecular Movies, Department of Chemistry, University of Copenhagen, Universitetsparken 5, DK-2100 København Ø, Denmark, and Center for Molecular Movies, Department of Chemistry, Technical University of Denmark, DTU 207, DK-2800 Lyngby, Denmark
| | - Klaus B. Møller
- Center for Molecular Movies, Department of Chemistry, University of Copenhagen, Universitetsparken 5, DK-2100 København Ø, Denmark, and Center for Molecular Movies, Department of Chemistry, Technical University of Denmark, DTU 207, DK-2800 Lyngby, Denmark
| | - Theis I. Sølling
- Center for Molecular Movies, Department of Chemistry, University of Copenhagen, Universitetsparken 5, DK-2100 København Ø, Denmark, and Center for Molecular Movies, Department of Chemistry, Technical University of Denmark, DTU 207, DK-2800 Lyngby, Denmark
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Aliphatic C–X (X=halogen) bond activation by transition metal complexes containing the {Pt2S2} core: A theoretical study of the reaction mechanism. Inorganica Chim Acta 2006. [DOI: 10.1016/j.ica.2006.02.021] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Wang Y, Zhang S, Zheng Q, Zhang B. C–Br bond fission dynamics in ultraviolet photodissociation of 1,2-dibromoethane. Chem Phys Lett 2006. [DOI: 10.1016/j.cplett.2006.03.048] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Yuan LW, Zhu JY, Wang YQ, Wang L, Bai JL, He GZ. Real-time investigation of the photodissociation dynamics of p-chlorotoluene and p-dichlorobenzene. Chem Phys Lett 2005. [DOI: 10.1016/j.cplett.2005.05.103] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Menšı́k M, Nešpůrek S. Vibrational coherence in excited state decay: the role of the type of electron-vibrational interactions. Chem Phys 2004. [DOI: 10.1016/j.chemphys.2004.04.012] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Affiliation(s)
- Theis I. Sølling
- Arthur Amos Noyes Laboratory of Chemical Physics, California Institute of Technology, Pasadena, California 91125
| | - Carsten Kötting
- Arthur Amos Noyes Laboratory of Chemical Physics, California Institute of Technology, Pasadena, California 91125
| | - Ahmed H. Zewail
- Arthur Amos Noyes Laboratory of Chemical Physics, California Institute of Technology, Pasadena, California 91125
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Lee YR, Chen CC, Lin SM. Photodissociation of CH2Br2, 1,1- and 1,2-C2H4Br2 at 248 nm: A simple C–Br bond fission versus a concerted three-body formation. J Chem Phys 2003. [DOI: 10.1063/1.1573187] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
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