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Schaffner D, Juncker von Buchwald T, Karaev E, Alagia M, Richter R, Stranges S, Coriani S, Fischer I. The x-ray absorption spectrum of the tert-butyl radical: An experimental and computational investigation. J Chem Phys 2024; 161:034309. [PMID: 39017428 DOI: 10.1063/5.0216364] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2024] [Accepted: 06/16/2024] [Indexed: 07/18/2024] Open
Abstract
We report the x-ray absorption spectrum (XAS) of the tert-butyl radical, C4H9. The radical was generated pyrolytically from azo-tert-butane, and the XAS of the pure radical was obtained by subtraction of spectra recorded at different temperatures. The bands in the XAS were assigned by ab initio calculations that are in very good agreement with the experimental data. The lowest energy signal in the XAS is assigned to the C1s electron transition from the central carbon atom to the singly occupied molecular orbital (SOMO), while higher transitions correspond to C1s excitations from terminal carbon atoms. Furthermore, we investigated the fragmentation of the radical following resonant C1s excitation by electron-ion-coincidence spectroscopy. Several fragmentation channels were identified. The C1s excitation of the terminal carbons is associated with a stronger fragmentation tendency compared to the lowest C1s excitation of the central carbon into the SOMO. For this core excited state, we still observe an intact parent ion, C4H9+, and a comparatively higher tendency to dissociate into CH3+ + C3H6+.
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Affiliation(s)
- Dorothee Schaffner
- Institute of Physical and Theoretical Chemistry, University of Würzburg, D-97074 Würzburg, Germany
| | | | - Emil Karaev
- Institute of Physical and Theoretical Chemistry, University of Würzburg, D-97074 Würzburg, Germany
| | - Michele Alagia
- CNR-Istituto Officina dei Materiali (IOM), Laboratorio TASC, 34149 Trieste, Italy
| | - Robert Richter
- Elettra-Sincrotrone Trieste, Area Science Park, I-34149 Basovizza, Trieste, Italy
| | - Stefano Stranges
- CNR-Istituto Officina dei Materiali (IOM), Laboratorio TASC, I-34149 Trieste, Italy
- Dipartimento di Chimica e Tecnologia dei Farmaci, Università degli Studi di Roma "La Sapienza," Piazzale Aldo Moro 5, I-00185 Rome, Italy
| | - Sonia Coriani
- DTU Chemistry, Technical University of Denmark, DK-2800 Kgs. Lyngby, Denmark
| | - Ingo Fischer
- Institute of Physical and Theoretical Chemistry, University of Würzburg, D-97074 Würzburg, Germany
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2
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Garg D, Chopra P, Lee JWL, Tikhonov DS, Kumar S, Akcaalan O, Allum F, Boll R, Butler AA, Erk B, Gougoula E, Gruet SP, He L, Heathcote D, Jones E, Kazemi MM, Lahl J, Lemmens AK, Liu Z, Loru D, Maclot S, Mason R, Merrick J, Müller E, Mullins T, Papadopoulou CC, Passow C, Peschel J, Plach M, Ramm D, Robertson P, Rompotis D, Simao A, Steber AL, Tajalli A, Tul-Noor A, Vadassery N, Vinklárek IS, Techert S, Küpper J, Rijs AM, Rolles D, Brouard M, Bari S, Eng-Johnsson P, Vallance C, Burt M, Manschwetus B, Schnell M. Ultrafast dynamics of fluorene initiated by highly intense laser fields. Phys Chem Chem Phys 2024. [PMID: 38958416 DOI: 10.1039/d3cp05063g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/04/2024]
Abstract
We present an investigation of the ultrafast dynamics of the polycyclic aromatic hydrocarbon fluorene initiated by an intense femtosecond near-infrared laser pulse (810 nm) and probed by a weak visible pulse (405 nm). Using a multichannel detection scheme (mass spectra, electron and ion velocity-map imaging), we provide a full disentanglement of the complex dynamics of the vibronically excited parent molecule, its excited ionic states, and fragments. We observed various channels resulting from the strong-field ionization regime. In particular, we observed the formation of the unstable tetracation of fluorene, above-threshold ionization features in the photoelectron spectra, and evidence of ubiquitous secondary fragmentation. We produced a global fit of all observed time-dependent photoelectron and photoion channels. This global fit includes four parent ions extracted from the mass spectra, 15 kinetic-energy-resolved ionic fragments extracted from ion velocity map imaging, and five photoelectron channels obtained from electron velocity map imaging. The fit allowed for the extraction of 60 lifetimes of various metastable photoinduced intermediates.
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Affiliation(s)
- Diksha Garg
- Deutsches Elektronen-Synchrotron DESY, Hamburg, Germany.
- Department of Physics, Universität Hamburg, Hamburg, Germany
| | - Pragya Chopra
- Deutsches Elektronen-Synchrotron DESY, Hamburg, Germany.
- Institute of Physical Chemistry, Christian-Albrechts-Universität zu Kiel, Kiel, Germany
| | - Jason W L Lee
- Deutsches Elektronen-Synchrotron DESY, Hamburg, Germany.
- Chemistry Research Laboratory, Department of Chemistry, University of Oxford, Oxford, UK
| | | | - Sonu Kumar
- Deutsches Elektronen-Synchrotron DESY, Hamburg, Germany.
- Department of Physics, Universität Hamburg, Hamburg, Germany
| | | | - Felix Allum
- Chemistry Research Laboratory, Department of Chemistry, University of Oxford, Oxford, UK
| | | | - Alexander A Butler
- Chemistry Research Laboratory, Department of Chemistry, University of Oxford, Oxford, UK
| | - Benjamin Erk
- Deutsches Elektronen-Synchrotron DESY, Hamburg, Germany.
| | - Eva Gougoula
- Deutsches Elektronen-Synchrotron DESY, Hamburg, Germany.
| | | | - Lanhai He
- Center for Free-Electron Laser Science CFEL, Deutsches Elektronen-Synchrotron DESY, Germany
| | - David Heathcote
- Chemistry Research Laboratory, Department of Chemistry, University of Oxford, Oxford, UK
| | - Ellen Jones
- Chemistry Research Laboratory, Department of Chemistry, University of Oxford, Oxford, UK
| | - Mehdi M Kazemi
- Deutsches Elektronen-Synchrotron DESY, Hamburg, Germany.
| | - Jan Lahl
- Department of Physics, Lund University, Lund, Sweden
| | - Alexander K Lemmens
- Van't Hoff Institute for Molecular Sciences, University of Amsterdam, Amsterdam, The Netherlands
- FELIX Laboratory, Radboud University, Nijmegen, The Netherlands
| | - Zhihao Liu
- Chemistry Research Laboratory, Department of Chemistry, University of Oxford, Oxford, UK
| | - Donatella Loru
- Deutsches Elektronen-Synchrotron DESY, Hamburg, Germany.
| | | | - Robert Mason
- Chemistry Research Laboratory, Department of Chemistry, University of Oxford, Oxford, UK
| | - James Merrick
- Chemistry Research Laboratory, Department of Chemistry, University of Oxford, Oxford, UK
| | - Erland Müller
- Deutsches Elektronen-Synchrotron DESY, Hamburg, Germany.
| | - Terry Mullins
- Center for Free-Electron Laser Science CFEL, Deutsches Elektronen-Synchrotron DESY, Germany
- European XFEL, Schenefeld, Germany
| | | | | | | | - Marius Plach
- Department of Physics, Lund University, Lund, Sweden
| | - Daniel Ramm
- Deutsches Elektronen-Synchrotron DESY, Hamburg, Germany.
| | - Patrick Robertson
- Chemistry Research Laboratory, Department of Chemistry, University of Oxford, Oxford, UK
| | - Dimitrios Rompotis
- Deutsches Elektronen-Synchrotron DESY, Hamburg, Germany.
- European XFEL, Schenefeld, Germany
| | - Alcides Simao
- Deutsches Elektronen-Synchrotron DESY, Hamburg, Germany.
| | | | - Ayhan Tajalli
- Deutsches Elektronen-Synchrotron DESY, Hamburg, Germany.
| | - Atia Tul-Noor
- Deutsches Elektronen-Synchrotron DESY, Hamburg, Germany.
| | - Nidin Vadassery
- Center for Free-Electron Laser Science CFEL, Deutsches Elektronen-Synchrotron DESY, Germany
- Department of Chemistry, Universität Hamburg, Hamburg, Germany
| | - Ivo S Vinklárek
- Center for Free-Electron Laser Science CFEL, Deutsches Elektronen-Synchrotron DESY, Germany
| | - Simone Techert
- Deutsches Elektronen-Synchrotron DESY, Hamburg, Germany.
| | - Jochen Küpper
- Center for Free-Electron Laser Science CFEL, Deutsches Elektronen-Synchrotron DESY, Germany
- Department of Physics, Universität Hamburg, Hamburg, Germany
- Center for Ultrafast Imaging, Universität Hamburg, Hamburg, Germany
- Department of Chemistry, Universität Hamburg, Hamburg, Germany
| | - Anouk M Rijs
- Division of BioAnalytical Chemistry, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
| | - Daniel Rolles
- J. R. Macdonald Laboratory, Department of Physics, Kansas State University, Manhattan, KS, USA
| | - Mark Brouard
- Chemistry Research Laboratory, Department of Chemistry, University of Oxford, Oxford, UK
| | - Sadia Bari
- Deutsches Elektronen-Synchrotron DESY, Hamburg, Germany.
- Zernike Institute for Advanced Materials, University of Groningen, Groningen, The Netherlands
| | | | - Claire Vallance
- Chemistry Research Laboratory, Department of Chemistry, University of Oxford, Oxford, UK
| | - Michael Burt
- Chemistry Research Laboratory, Department of Chemistry, University of Oxford, Oxford, UK
| | | | - Melanie Schnell
- Deutsches Elektronen-Synchrotron DESY, Hamburg, Germany.
- Institute of Physical Chemistry, Christian-Albrechts-Universität zu Kiel, Kiel, Germany
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3
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Leone SR. Reinvented: An Attosecond Chemist. Annu Rev Phys Chem 2024; 75:1-19. [PMID: 38012050 DOI: 10.1146/annurev-physchem-083122-011610] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2023]
Abstract
Attosecond science requires a substantial rethinking of how to make measurements on very short timescales; how to acquire the necessary equipment, technology, and personnel; and how to build a set of laboratories for such experiments. This entails a rejuvenation of the author in many respects, in the laboratory itself, with regard to students and postdocs, and in generating funding for research. It also brings up questions of what it means to do attosecond science, and the discovery of the power of X-ray spectroscopy itself, which complements the short timescales addressed. The lessons learned, expressed in the meanderings of this autobiographical article, may be of benefit to others who try to reinvent themselves.
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Affiliation(s)
- Stephen R Leone
- Departments of Chemistry and Physics and Lawrence Berkeley National Laboratory, University of California, Berkeley, California, USA;
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4
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Reinwardt S, Cieslik P, Buhr T, Perry-Sassmannshausen A, Schippers S, Müller A, Trinter F, Martins M. Isomer-specific photofragmentation of C 3H 3+ at the carbon K-edge. Phys Chem Chem Phys 2024; 26:15519-15529. [PMID: 38752716 DOI: 10.1039/d4cp00370e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/30/2024]
Abstract
Individual fingerprints of different isomers of C3H3+ cations have been identified by studying photoionization, photoexcitation, and photofragmentation of C3H3+ near the carbon K-edge. The experiment was performed employing the photon-ion merged-beams technique at the photon-ion spectrometer at PETRA III (PIPE). This technique is a variant of near-edge X-ray absorption fine-structure spectroscopy, which is particularly sensitive to the 1s → π* excitation. The C3H3+ primary ions were generated by an electron cyclotron resonance ion source. C3Hn2+ product ions with n = 0, 1, 2, and 3 were observed for photon energies in the range of 279.0 eV to 295.2 eV. The experimental spectra are interpreted with the aid of theoretical calculations within the framework of time-dependent density functional theory. To this end, absorption spectra have been calculated for three different constitutional isomers of C3H3+. We find that our experimental approach offers a new possibility to study at the same time details of the electronic structure and of the geometry of molecular ions such as C3H3+.
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Affiliation(s)
- Simon Reinwardt
- Institut für Experimentalphysik, Universität Hamburg, Luruper Chaussee 149, 22761 Hamburg, Germany.
| | - Patrick Cieslik
- Institut für Experimentalphysik, Universität Hamburg, Luruper Chaussee 149, 22761 Hamburg, Germany.
| | - Ticia Buhr
- I. Physikalisches Institut, Justus-Liebig-Universität Gießen, Leihgesterner Weg 217, 35292 Gießen, Germany
| | | | - Stefan Schippers
- I. Physikalisches Institut, Justus-Liebig-Universität Gießen, Leihgesterner Weg 217, 35292 Gießen, Germany
| | - Alfred Müller
- I. Physikalisches Institut, Justus-Liebig-Universität Gießen, Leihgesterner Weg 217, 35292 Gießen, Germany
| | - Florian Trinter
- Molecular Physics, Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, 14195 Berlin, Germany
| | - Michael Martins
- Institut für Experimentalphysik, Universität Hamburg, Luruper Chaussee 149, 22761 Hamburg, Germany.
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5
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Garner SM, Haugen EA, Leone SR, Neuscamman E. Spin Coupling Effect on Geometry-Dependent X-Ray Absorption of Diradicals. J Am Chem Soc 2024; 146:2387-2397. [PMID: 38235992 DOI: 10.1021/jacs.3c08002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2024]
Abstract
We theoretically investigate the influence of diradical electron spin coupling on the time-resolved X-ray absorption spectra of the photochemical ring opening of furanone. We predict geometry-dependent carbon K-edge signals involving transitions from core orbitals to both singly and unoccupied molecular orbitals. The most obvious features of the ring opening come from the carbon atom directly involved in the bond breaking through its transition to both the newly formed singly occupied and the available lowest unoccupied molecular orbitals (SOMO and LUMO, respectively). In addition to this primary feature, the singlet spin coupling of four unpaired electrons that arises in the core-to-LUMO states creates additional geometry dependence in some spectral features with both oscillator strengths and relative excitation energies varying observably as a function of the ring opening. We attribute this behavior to a spin-occupancy-induced selection rule, which occurs when singlet spin coupling is enforced in the diradical state. Notably, one of these geometry-sensitive core-to-LUMO transitions excites core electrons from a backbone carbon not involved in the bond breaking, providing a novel nonlocal X-ray probe of chemical dynamics arising from electron spin coupling.
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Affiliation(s)
- Scott M Garner
- Department of Chemistry, University of California, Berkeley, California 94720, United States
- Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Eric A Haugen
- Department of Chemistry, University of California, Berkeley, California 94720, United States
- Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Stephen R Leone
- Department of Chemistry, University of California, Berkeley, California 94720, United States
- Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
- Department of Physics, University of California, Berkeley, California 94720, United States
| | - Eric Neuscamman
- Department of Chemistry, University of California, Berkeley, California 94720, United States
- Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
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6
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Tikhonov DS, Vishnevskiy YV. Describing nuclear quantum effects in vibrational properties using molecular dynamics with Wigner sampling. Phys Chem Chem Phys 2023. [PMID: 37401424 DOI: 10.1039/d3cp01007d] [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
In this work we discuss the generally applicable Wigner sampling and introduce a new, simplified Wigner sampling method, for computationally effective modeling of molecular properties containing nuclear quantum effects and vibrational anharmonicity. For various molecular systems test calculations of (a) vibrationally averaged rotational constants, (b) vibrational IR spectra and (c) photoelectron spectra have been performed. The performance of Wigner sampling has been assessed by comparing with experimental data and with results of other theoretical models, including harmonic and VPT2 approximations. The developed simplified Wigner sampling method shows advantages in application to large and flexible molecules.
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Affiliation(s)
- Denis S Tikhonov
- Deutsches Elektronen-Synchrotron DESY, Notkestr. 85, 22607 Hamburg, Germany.
| | - Yury V Vishnevskiy
- 2Lehrstuhl für Anorganische Chemie und Strukturchemie, Fakultät für Chemie, Universität Bielefeld, Universitätsstr. 25, 33615 Bielefeld, Germany.
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7
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Marin K, Huang M, Evangelista FA. Signatures of diradicals in x-ray absorption spectroscopy. J Chem Phys 2023; 158:2882842. [PMID: 37094006 DOI: 10.1063/5.0140761] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2022] [Accepted: 03/09/2023] [Indexed: 04/26/2023] Open
Abstract
Theoretical simulations are critical to analyze and interpret the x-ray absorption spectrum of transient open-shell species. In this work, we propose a model of the many-body core-excited states of symmetric diradicals. We apply this model to analyze the carbon K-edge transitions of o-, m-, and p-benzyne, three organic diradicals with diverse and unusual electronic structures. The predictions of our model are compared with high-level multireference computations of the K-edge spectrum of the benzynes obtained with the driven similarity renormalization group truncated to third order. Our model shows the importance of a many-body treatment of the core-excited states of the benzynes and provides a theoretical framework to understand which properties of the ground state of these diradicals can be extracted from their x-ray spectrum.
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Affiliation(s)
- Kevin Marin
- Department of Chemistry and Cherry Emerson Center for Scientific Computation, Emory University, Atlanta, Georgia 30322, USA
| | - Meng Huang
- Department of Chemistry and Cherry Emerson Center for Scientific Computation, Emory University, Atlanta, Georgia 30322, USA
| | - Francesco A Evangelista
- Department of Chemistry and Cherry Emerson Center for Scientific Computation, Emory University, Atlanta, Georgia 30322, USA
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8
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Huang M, Evangelista FA. A study of core-excited states of organic molecules computed with the generalized active space driven similarity renormalization group. J Chem Phys 2023; 158:124112. [PMID: 37003756 DOI: 10.1063/5.0137096] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/03/2023] Open
Abstract
This work examines the accuracy and precision of x-ray absorption spectra computed with a multireference approach that combines generalized active space (GAS) references with the driven similarity renormalization group (DSRG). We employ the x-ray absorption benchmark of organic molecule (XABOOM) set, consisting of 116 transitions from mostly organic molecules [Fransson et al., J. Chem. Theory Comput. 17, 1618 (2021)]. Several approximations to a full-valence active space are examined and benchmarked. Absolute excitation energies and intensities computed with the GAS-DSRG truncated to second-order in perturbation theory are found to systematically underestimate experimental and reference theoretical values. Third-order perturbative corrections significantly improve the accuracy of GAS-DSRG absolute excitation energies, bringing the mean absolute deviation from experimental values down to 0.32 eV. The ozone molecule and glyoxylic acid are particularly challenging for second-order perturbation theory and are examined in detail to assess the importance of active space truncation and intruder states.
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Affiliation(s)
- Meng Huang
- Department of Chemistry and Cherry Emerson Center for Scientific Computation, Emory University, Atlanta, Georgia 30322, USA
| | - Francesco A Evangelista
- Department of Chemistry and Cherry Emerson Center for Scientific Computation, Emory University, Atlanta, Georgia 30322, USA
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9
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Sekikawa T, Saito N, Kurimoto Y, Ishii N, Mizuno T, Kanai T, Itatani J, Saita K, Taketsugu T. Real-time observation of the Woodward-Hoffmann rule for 1,3-cyclohexadiene by femtosecond soft X-ray transient absorption. Phys Chem Chem Phys 2023; 25:8497-8506. [PMID: 36883468 DOI: 10.1039/d2cp05268g] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/18/2023]
Abstract
The stereochemistry of pericyclic reactions is explained by orbital symmetry conservation, referred to as the Woodward-Hoffmann (WH) rule. Although this rule has been verified using the structures of reactants and products, the temporal evolution of the orbital symmetry during the reaction has not been clarified. Herein, we used femtosecond soft X-ray transient absorption spectroscopy to elucidate the thermal pericyclic reaction of 1,3-cyclohexadiene (CHD) molecules, i.e., their isomerization to 1,3,5-hexatriene. In the present experimental scheme, the ring-opening reaction is driven by the thermal vibrational energy induced by photoexcitation to the Rydberg states at 6.2 eV and subsequent femtosecond relaxation to the ground state of CHD molecules. The direction of the ring opening, which can be conrotatory or disrotatory, was the primary focus, and the WH rule predicts the disrotatory pathway in the thermal process. We observed the shifts in K-edge absorption of the carbon atom from the 1s orbital to vacant molecular orbitals around 285 eV at a delay between 340 and 600 fs. Furthermore, a theoretical investigation predicts that the shifts depend on the molecular structures along the reaction pathways and the observed shifts in induced absorption are attributed to the structural change in the disrotatory pathway. This confirms that the orbital symmetry is dynamically conserved in the ring-opening reaction of CHD molecules as predicted using the WH rule.
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Affiliation(s)
- Taro Sekikawa
- Department of Applied Physics, Faculty of Engineering, Hokkaido University, Sapporo 060-8628, Japan.
| | - Nariyuki Saito
- Institute for Solid State Physics, University of Tokyo, Kashiwa 277-8581, Japan
| | - Yutaro Kurimoto
- Department of Applied Physics, Faculty of Engineering, Hokkaido University, Sapporo 060-8628, Japan.
| | - Nobuhisa Ishii
- Kansai Photon Science Institute, National Institutes for Quantum and Radiological Science and Technology, Kizugawa 619-0215, Japan
| | - Tomoya Mizuno
- Institute for Solid State Physics, University of Tokyo, Kashiwa 277-8581, Japan
| | - Teruto Kanai
- Institute for Solid State Physics, University of Tokyo, Kashiwa 277-8581, Japan
| | - Jiro Itatani
- Institute for Solid State Physics, University of Tokyo, Kashiwa 277-8581, Japan
| | - Kenichiro Saita
- Department of Chemistry, Faculty of Science, Hokkaido University, Sapporo 060-0810, Japan
| | - Tetsuya Taketsugu
- Department of Chemistry, Faculty of Science, Hokkaido University, Sapporo 060-0810, Japan
- Institute for Chemical Reaction Design and Discovery (WPI-ICReDD), Hokkaido University, Sapporo 001-0021, Japan
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10
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Muchova E, Hollas D, Holland DMP, Bacellar C, Leroy L, Barillot TR, Longetti L, Coreno M, de Simone M, Grazioli C, Chergui M, Ingle RA. Jahn-Teller effects in initial and final states: high-resolution X-ray absorption, photoelectron and Auger spectroscopy of allene. Phys Chem Chem Phys 2023; 25:6733-6745. [PMID: 36799466 DOI: 10.1039/d2cp05299g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/18/2023]
Abstract
Carbon K-edge resonant Auger spectra of gas-phase allene following excitation of the pre-edge 1s → π* transitions are presented and analysed with the support of EOM-CCSD/cc-pVTZ calculations. X-Ray absorption (XAS), X-ray photoelectron (XPS), valence band and non-resonant Auger spectra are also reanalysed with a series of computational approaches. The results presented demonstrate the importance of including nuclear ensemble effects for simulating X-ray observables and as an effective strategy for capturing Jahn-Teller effects in spectra.
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Affiliation(s)
- Eva Muchova
- Department of Physical Chemistry, University of Chemistry and Technology, Technická 5, 166 28 Prague, Czech Republic
| | - Daniel Hollas
- Centre for Computational Chemistry, School of Chemistry, University of Bristol, Bristol, BS8 1TS, UK
| | | | - Camila Bacellar
- Laboratoire de Spectroscopie Ultrarapide, Ecole Polytechnique Fédérale de Lausanne, ISIC, FSB, CH-1015 Lausanne, Switzerland
| | - Ludmila Leroy
- Laboratoire de Spectroscopie Ultrarapide, Ecole Polytechnique Fédérale de Lausanne, ISIC, FSB, CH-1015 Lausanne, Switzerland
| | - Thomas R Barillot
- Laboratoire de Spectroscopie Ultrarapide, Ecole Polytechnique Fédérale de Lausanne, ISIC, FSB, CH-1015 Lausanne, Switzerland
| | - Luca Longetti
- Laboratoire de Spectroscopie Ultrarapide, Ecole Polytechnique Fédérale de Lausanne, ISIC, FSB, CH-1015 Lausanne, Switzerland
| | - Marcello Coreno
- ISM-CNR, Istituto di Struttura dei Materiali, LD2 Unit, 34149 Trieste, Italy
| | | | - Cesare Grazioli
- IOM-CNR, Istituto Officina dei Materiali, 34149 Trieste, Italy
| | - Majed Chergui
- Laboratoire de Spectroscopie Ultrarapide, Ecole Polytechnique Fédérale de Lausanne, ISIC, FSB, CH-1015 Lausanne, Switzerland
| | - Rebecca A Ingle
- Department of Chemistry, 20 Gordon Street, London, WC1H 0AJ, UK.
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11
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Epshtein M, Tenorio BNC, Vidal ML, Scutelnic V, Yang Z, Xue T, Krylov AI, Coriani S, Leone SR. Signatures of the Bromine Atom and Open-Shell Spin Coupling in the X-ray Spectrum of the Bromobenzene Cation. J Am Chem Soc 2023; 145:3554-3560. [PMID: 36735829 DOI: 10.1021/jacs.2c12334] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Tabletop X-ray spectroscopy measurements at the carbon K-edge complemented by ab initio calculations are used to investigate the influence of the bromine atom on the carbon core-valence transitions in the bromobenzene cation (BrBz+). The electronic ground state of the cation is prepared by resonance-enhanced two-photon ionization of neutral bromobenzene (BrBz) and probed by X-rays produced by high-harmonic generation (HHG). Replacing one of the hydrogen atoms in benzene with a bromine atom shifts the transition from the 1sC* orbital of the carbon atom (C*) bonded to bromine by ∼1 eV to higher energy in the X-ray spectrum compared to the other carbon atoms (C). Moreover, in BrBz+, the X-ray spectrum is dominated by two relatively intense transitions, 1sC→π* and 1sC*→σ*(C*-Br), where the second transition is enhanced relative to the neutral BrBz. In addition, a doublet peak shape for these two transitions is observed in the experiment. The 1sC→π* doublet peak shape arises due to the spin coupling of the unpaired electron in the partially vacant π orbital (from ionization) with the two other unpaired electrons resulting from the transition from the 1sC core orbital to the fully vacant π* orbitals. The 1sC*→σ* doublet peak shape results from several transitions involving σ* and vibrational C*-Br mode activations following the UV ionization, which demonstrates the impact of the C*-Br bond length on the core-valence transition as well as on the relaxation geometry of BrBz+.
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Affiliation(s)
- Michael Epshtein
- Department of Chemistry, University of California, Berkeley, California 94720, United States.,Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | | | - Marta L Vidal
- DTU Chemistry─Department of Chemistry, Technical University of Denmark, DK-2800 Kongens Lyngby, Denmark
| | - Valeriu Scutelnic
- Department of Chemistry, University of California, Berkeley, California 94720, United States.,Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Zheyue Yang
- Department of Chemistry, University of California, Berkeley, California 94720, United States
| | - Tian Xue
- Department of Chemistry, University of California, Berkeley, California 94720, United States
| | - Anna I Krylov
- Department of Chemistry, University of Southern California, Los Angeles, California 90089, United States
| | - Sonia Coriani
- DTU Chemistry─Department of Chemistry, Technical University of Denmark, DK-2800 Kongens Lyngby, Denmark
| | - Stephen R Leone
- Department of Chemistry, University of California, Berkeley, California 94720, United States.,Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States.,Department of Physics, University of California, Berkeley, California 94720, United States
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12
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Jayadev NK, Ferino-Pérez A, Matz F, Krylov AI, Jagau TC. The Auger spectrum of benzene. J Chem Phys 2023; 158:064109. [PMID: 36792526 DOI: 10.1063/5.0138674] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
We present an ab initio computational study of the Auger electron spectrum of benzene. Auger electron spectroscopy exploits the Auger-Meitner effect, and although it is established as an analytic technique, the theoretical modeling of molecular Auger spectra from first principles remains challenging. Here, we use coupled-cluster theory and equation-of-motion coupled-cluster theory combined with two approaches to describe the decaying nature of core-ionized states: (i) Feshbach-Fano resonance theory and (ii) the method of complex basis functions. The spectra computed with these two approaches are in excellent agreement with each other and also agree well with experimental Auger spectra of benzene. The Auger spectrum of benzene features two well-resolved peaks at Auger electron energies above 260 eV, which correspond to final states with two electrons removed from the 1e1g and 3e2g highest occupied molecular orbitals. At lower Auger electron energies, the spectrum is less well resolved, and the peaks comprise multiple final states of the benzene dication. In line with theoretical considerations, singlet decay channels contribute more to the total Auger intensity than the corresponding triplet decay channels.
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Affiliation(s)
- Nayanthara K Jayadev
- Department of Chemistry, University of Southern California, Los Angeles, California 90089, USA
| | | | - Florian Matz
- Department of Chemistry, KU Leuven, B-3001 Leuven, Belgium
| | - Anna I Krylov
- Department of Chemistry, University of Southern California, Los Angeles, California 90089, USA
| | - Thomas-C Jagau
- Department of Chemistry, KU Leuven, B-3001 Leuven, Belgium
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13
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Haugen EA, Hait D, Scutelnic V, Xue T, Head-Gordon M, Leone SR. Ultrafast X-ray Spectroscopy of Intersystem Crossing in Hexafluoroacetylacetone: Chromophore Photophysics and Spectral Changes in the Face of Electron-Withdrawing Groups. J Phys Chem A 2023; 127:634-644. [PMID: 36638240 DOI: 10.1021/acs.jpca.2c06044] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Intersystem crossings between singlet and triplet states represent a crucial relaxation pathway in photochemical processes. Herein, we probe the intersystem crossing in hexafluoro-acetylacetone with ultrafast X-ray transient absorption spectroscopy at the carbon K-edge. We observe the excited state dynamics following excitation with 266 nm UV light to the 1ππ* (S2) state with element and site-specificity using a broadband soft X-ray pulse produced by high harmonic generation. These results are compared to X-ray spectra computed from orbital optimized density functional theory methods. It is found that the electron-withdrawing fluorine atoms decongest the X-ray absorption spectrum by enhancing separation between features originating from different carbon atoms. This facilitates the elucidation of structural and electronic dynamics at the chromophore. The evolution of the core-to-valence resonances at the carbon K-edge reveals an ultrafast population transfer between the 1nπ* (S1) and 3ππ* (T1) states on a 1.6 ± 0.4 ps time scale, which is similar to the 1.5 ps time scale earlier observed for acetylacetone [ J. Am. Chem. Soc. 2017, 139, 16576-16583, DOI: 10.1021/jacs.7b07532]. It therefore appears that terminal fluorination has little influence on the intersystem crossing rate of the acetylacetone chromophore. In addition, the significant role of hydrogen-bond opened and twisted rotational isomers is elucidated in the excited state dynamics by comparison of the experimental transient X-ray spectra with theory.
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Affiliation(s)
- Eric A Haugen
- Department of Chemistry, University of California, Berkeley, California 94720, United States.,Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Diptarka Hait
- Department of Chemistry, University of California, Berkeley, California 94720, United States.,Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Valeriu Scutelnic
- Department of Chemistry, University of California, Berkeley, California 94720, United States.,Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Tian Xue
- Department of Chemistry, University of California, Berkeley, California 94720, United States.,Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Martin Head-Gordon
- Department of Chemistry, University of California, Berkeley, California 94720, United States.,Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Stephen R Leone
- Department of Chemistry, University of California, Berkeley, California 94720, United States.,Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States.,Department of Physics, University of California, Berkeley, California 94720, United States
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14
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Arias-Martinez JE, Cunha LA, Oosterbaan KJ, Lee J, Head-Gordon M. Accurate core excitation and ionization energies from a state-specific coupled-cluster singles and doubles approach. Phys Chem Chem Phys 2022; 24:20728-20741. [PMID: 36004629 DOI: 10.1039/d2cp01998a] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We investigate the use of orbital-optimized references in conjunction with single-reference coupled-cluster theory with single and double substitutions (CCSD) for the study of core excitations and ionizations of 18 small organic molecules, without the use of response theory or equation-of-motion (EOM) formalisms. Three schemes are employed to successfully address the convergence difficulties associated with the coupled-cluster equations, and the spin contamination resulting from the use of a spin symmetry-broken reference, in the case of excitations. In order to gauge the inherent potential of the methods studied, an effort is made to provide reasonable basis set limit estimates for the transition energies. Overall, we find that the two best-performing schemes studied here for ΔCCSD are capable of predicting excitation and ionization energies with errors comparable to experimental accuracies. The proposed ΔCCSD schemes reduces statistical errors against experimental excitation energies by more than a factor of two when compared to the frozen-core core-valence separated (FC-CVS) EOM-CCSD approach - a successful variant of EOM-CCSD tailored towards core excitations.
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Affiliation(s)
- Juan E Arias-Martinez
- Kenneth S. Pitzer Center for Theoretical Chemistry, Department of Chemistry, University of California, Berkeley, California 94720, USA. .,Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Leonardo A Cunha
- Kenneth S. Pitzer Center for Theoretical Chemistry, Department of Chemistry, University of California, Berkeley, California 94720, USA. .,Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Katherine J Oosterbaan
- Kenneth S. Pitzer Center for Theoretical Chemistry, Department of Chemistry, University of California, Berkeley, California 94720, USA.
| | - Joonho Lee
- Department of Chemistry, Columbia University, New York 10027, USA
| | - Martin Head-Gordon
- Kenneth S. Pitzer Center for Theoretical Chemistry, Department of Chemistry, University of California, Berkeley, California 94720, USA. .,Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
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15
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Carravetta V, Couto RC, Ågren H. X-ray absorption of molecular cations-a new challenge for electronic structure theory. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2022; 34:363002. [PMID: 35767974 DOI: 10.1088/1361-648x/ac7d2a] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/16/2022] [Accepted: 06/29/2022] [Indexed: 06/15/2023]
Abstract
In this paper we put forward some historical notes on the development of computational chemistry toward applications of x-ray spectroscopies. We highlight some of the important contributions by Enrico Clementi as method and program developer and as a supporter of this branch of computational research. We bring up a modern example based on the very recent experimental development of x-ray absorption of cationic molecules. As we show this spectroscopy poses new challenges for electronic structure theory and the electron correlation problem.
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Affiliation(s)
- V Carravetta
- Institute of Physical Chemical Processes-CNR, via Moruzzi 1, 56124 Pisa, Italy
| | - R C Couto
- Department of Theoretical Chemistry and Biology, School of Chemistry, Biotechnology and Health, Royal Institute of Technology, SE-106 91 Stockholm, Sweden
| | - H Ågren
- Department of Physics and Astronomy, Uppsala University, Box 516, SE-751 20 Uppsala, Sweden
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16
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Ross AD, Hait D, Scutelnic V, Haugen EA, Ridente E, Balkew MB, Neumark DM, Head-Gordon M, Leone SR. Jahn-Teller Distortion and Dissociation of CCl 4+ by Transient X-ray Spectroscopy Simultaneously at the Carbon K- and Chlorine L-Edge. Chem Sci 2022; 13:9310-9320. [PMID: 36093014 PMCID: PMC9384822 DOI: 10.1039/d2sc02402k] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2022] [Accepted: 07/18/2022] [Indexed: 11/29/2022] Open
Abstract
X-ray Transient Absorption Spectroscopy (XTAS) and theoretical calculations are used to study CCl4+ prepared by 800 nm strong-field ionization. XTAS simultaneously probes atoms at the carbon K-edge (280–300 eV) and chlorine L-edge (195–220 eV). Comparison of experiment to X-ray spectra computed by orbital-optimized density functional theory (OO-DFT) indicates that after ionization, CCl4+ undergoes symmetry breaking driven by Jahn–Teller distortion away from the initial tetrahedral structure (Td) in 6 ± 2 fs. The resultant symmetry-broken covalently bonded form subsequently separates to a noncovalently bound complex between CCl3+ and Cl over 90 ± 10 fs, which is again predicted by theory. Finally, after more than 800 fs, L-edge signals for atomic Cl are observed, indicating dissociation to free CCl3+ and Cl. The results for Jahn–Teller distortion to the symmetry-broken form of CCl4+ and formation of the Cl–CCl+3 complex characterize previously unobserved new species along the route to dissociation. Dynamics of CCl4+ prepared by 800 nm strong-field ionization, as studied with X-ray transient absorption spectroscopy (XTAS) and quantum chemical calculations.![]()
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Affiliation(s)
- Andrew D Ross
- Department of Chemistry, University of California Berkeley 94720 CA USA
- Chemical Sciences Division, Lawrence Berkeley National Laboratory Berkeley 94720 CA USA
| | - Diptarka Hait
- Department of Chemistry, University of California Berkeley 94720 CA USA
- Chemical Sciences Division, Lawrence Berkeley National Laboratory Berkeley 94720 CA USA
| | - Valeriu Scutelnic
- Department of Chemistry, University of California Berkeley 94720 CA USA
- Chemical Sciences Division, Lawrence Berkeley National Laboratory Berkeley 94720 CA USA
| | - Eric A Haugen
- Department of Chemistry, University of California Berkeley 94720 CA USA
- Chemical Sciences Division, Lawrence Berkeley National Laboratory Berkeley 94720 CA USA
| | - Enrico Ridente
- Department of Chemistry, University of California Berkeley 94720 CA USA
| | - Mikias B Balkew
- School of Physics, Georgia Institute of Technology Atlanta 30332 GA USA
- Department of Chemistry, University of California Berkeley 94720 CA USA
| | - Daniel M Neumark
- Department of Chemistry, University of California Berkeley 94720 CA USA
- Chemical Sciences Division, Lawrence Berkeley National Laboratory Berkeley 94720 CA USA
| | - Martin Head-Gordon
- Department of Chemistry, University of California Berkeley 94720 CA USA
- Chemical Sciences Division, Lawrence Berkeley National Laboratory Berkeley 94720 CA USA
| | - Stephen R Leone
- Department of Chemistry, University of California Berkeley 94720 CA USA
- Chemical Sciences Division, Lawrence Berkeley National Laboratory Berkeley 94720 CA USA
- Department of Physics, University of California Berkeley 94720 CA USA
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17
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Wong ZC, Ungur L. Exploring vibronic coupling in the benzene radical cation and anion with different levels of the GW approximation. Phys Chem Chem Phys 2021; 23:19054-19070. [PMID: 34612443 DOI: 10.1039/d1cp02795f] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The linear vibronic coupling constants of the benzene radical cation and anion have been obtained with different levels of the GW approximation, including G0W0, eigenvalue self-consistent GW, and quasiparticle self-consistent GW, as well as DFT with the following exchange-correlation functionals: BLYP, B3LYP, CAM-B3LYP, tuned CAM-B3LYP, and an IP-tuned CAM-B3LYP functional. The vibronic coupling constants were calculated numerically using the gradients of the eigenvalues of the degenerate HOMOs and LUMOs of the neutral benzene molecule for DFT, while the numerical gradients of the quasiparticle energies were used in the case of GW. The results were evaluated against those of high level wave function methods in the literature, and the approximate self-consistent GW methods and G0W0 with long-range corrected functionals were found to yield the best results on the whole.
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Affiliation(s)
- Zi Cheng Wong
- Department of Chemistry, National University of Singapore, Block S8 Level 3, 3 Science Drive 3, 117543, Singapore.
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18
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Witwicki M, Lewińska A, Ozarowski A. o-Semiquinone radical anion isolated as an amorphous porous solid. Phys Chem Chem Phys 2021; 23:17408-17419. [PMID: 34351330 DOI: 10.1039/d1cp01596f] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The use of metal cations is a commonly applied strategy to create S > 1/2 stable molecular systems containing semiquinone radicals. Persistent mono-semiquinonato complexes of diamagnetic metal ions (S = 1/2) have been hitherto less common and mostly limited to the complexes of heavy metal ions. In this work, a mono-semiquinonato complex of aluminum, derived from 1,2-dihydroxybenzene, is obtained using a surprisingly short and uncomplicated procedure. The isolated product is an amorphous and porous solid that exhibits very good stability under ambient conditions. To characterise its molecular and electronic structure, 9.7, 34 and 406 GHz EPR spectroscopy was used in concert with computational techniques (DFT and DLPNO-CCSD). It was revealed that the radical complex is composed of two chemically equivalent aluminum cations and two catechol-like ligands with the unpaired electron uniformly distributed between the two organic molecules. The good stability and porous structure make this complex applicable in heterogeneous aerobic reactions.
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Affiliation(s)
- Maciej Witwicki
- Faculty of Chemistry, Wroclaw University, Joliot-Curie 14, 50-383 Wroclaw, Poland.
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19
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Scutelnic V, Tsuru S, Pápai M, Yang Z, Epshtein M, Xue T, Haugen E, Kobayashi Y, Krylov AI, Møller KB, Coriani S, Leone SR. X-ray transient absorption reveals the 1A u (nπ*) state of pyrazine in electronic relaxation. Nat Commun 2021; 12:5003. [PMID: 34408141 PMCID: PMC8373973 DOI: 10.1038/s41467-021-25045-0] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2021] [Accepted: 07/21/2021] [Indexed: 11/09/2022] Open
Abstract
Electronic relaxation in organic chromophores often proceeds via states not directly accessible by photoexcitation. We report on the photoinduced dynamics of pyrazine that involves such states, excited by a 267 nm laser and probed with X-ray transient absorption spectroscopy in a table-top setup. In addition to the previously characterized 1B2u (ππ*) (S2) and 1B3u (nπ*) (S1) states, the participation of the optically dark 1Au (nπ*) state is assigned by a combination of experimental X-ray core-to-valence spectroscopy, electronic structure calculations, nonadiabatic dynamics simulations, and X-ray spectral computations. Despite 1Au (nπ*) and 1B3u (nπ*) states having similar energies at relaxed geometry, their X-ray absorption spectra differ largely in transition energy and oscillator strength. The 1Au (nπ*) state is populated in 200 ± 50 femtoseconds after electronic excitation and plays a key role in the relaxation of pyrazine to the ground state.
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Affiliation(s)
- Valeriu Scutelnic
- Department of Chemistry, University of California, Berkeley, CA, USA
| | - Shota Tsuru
- DTU Chemistry, Technical University of Denmark, Kongens Lyngby, Denmark.,Ruhr-Universität, Bochum, Germany
| | - Mátyás Pápai
- DTU Chemistry, Technical University of Denmark, Kongens Lyngby, Denmark.,Wigner Research Centre for Physics, Budapest, Hungary
| | - Zheyue Yang
- Department of Chemistry, University of California, Berkeley, CA, USA.,, Shanghai, China
| | - Michael Epshtein
- Department of Chemistry, University of California, Berkeley, CA, USA.,Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA.,, Beer-Sheva, Israel
| | - Tian Xue
- Department of Chemistry, University of California, Berkeley, CA, USA
| | - Eric Haugen
- Department of Chemistry, University of California, Berkeley, CA, USA.,Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Yuki Kobayashi
- Department of Chemistry, University of California, Berkeley, CA, USA.,Stanford PULSE Institute, SLAC National Accelerator Laboratory, Menlo Park, CA, USA
| | - Anna I Krylov
- Department of Chemistry, University of Southern California, Los Angeles, CA, USA
| | - Klaus B Møller
- DTU Chemistry, Technical University of Denmark, Kongens Lyngby, Denmark
| | - Sonia Coriani
- DTU Chemistry, Technical University of Denmark, Kongens Lyngby, Denmark
| | - Stephen R Leone
- Department of Chemistry, University of California, Berkeley, CA, USA. .,Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA. .,Department of Physics, University of California, Berkeley, CA, USA.
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20
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Zhao R, Grofe A, Wang Z, Bao P, Chen X, Liu W, Gao J. Dynamic-then-Static Approach for Core Excitations of Open-Shell Molecules. J Phys Chem Lett 2021; 12:7409-7417. [PMID: 34328742 DOI: 10.1021/acs.jpclett.1c02039] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Delta self-consistent-field methods are widely used in studies of electronically excited states. However, the nonaufbau determinants are generally spin-contaminated. Here, we describe a general approach for spin-coupling interactions of open-shell molecules, making use of multistate density functional theory (MSDFT). In particular, the effective exchange integrals that determine spin coupling are obtained by enforcing the multiplet degeneracy of the S+1 state in the MS = S manifold. Consequently, they are consistent with the energy of the high-spin state that is adequately treated by Kohn-Sham density functional theory (DFT) and, thereby, free of double counting of correlation. The method was applied to core excitations of open-shell molecules and compared with those by spin-adapted time-dependent DFT. An excellent agreement with experiment was found employing the BLYP functional and aug-cc-pCVQZ basis set. Overall, MSDFT provides an effective combination of the strengths of DFT and wave function theory to achieve efficiency and accuracy.
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Affiliation(s)
- Ruoqi Zhao
- Institute of Systems and Physical Biology, Shenzhen Bay Laboratory, Shenzhen 518055, Guangdong, China
- Institute of Theoretical Chemistry, Jilin University Changchun 130023, Jilin, China
| | - Adam Grofe
- Institute of Theoretical Chemistry, Jilin University Changchun 130023, Jilin, China
| | - Zikuan Wang
- Qingdao Institute for Theoretical and Computational Sciences, Institute of Frontier and Interdisciplinary Science, Shandong University, Qingdao 266237, Shandong, China
| | - Peng Bao
- Beijing National Laboratory for Molecular Sciences, State Key Laboratory for Structural Chemistry of Unstable and Stable Species, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
| | - Xin Chen
- Institute of Systems and Physical Biology, Shenzhen Bay Laboratory, Shenzhen 518055, Guangdong, China
| | - Wenjian Liu
- Qingdao Institute for Theoretical and Computational Sciences, Institute of Frontier and Interdisciplinary Science, Shandong University, Qingdao 266237, Shandong, China
| | - Jiali Gao
- Institute of Systems and Physical Biology, Shenzhen Bay Laboratory, Shenzhen 518055, Guangdong, China
- Department of Chemistry and Supercomputing Institute, University of Minnesota, Minneapolis 55455, Minnesota, United States
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21
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Dobrowolski JC, Dudek WM, Karpińska G, Baraniak A. Substituent Effect in the Cation Radicals of Monosubstituted Benzenes. Int J Mol Sci 2021; 22:6936. [PMID: 34203254 PMCID: PMC8269098 DOI: 10.3390/ijms22136936] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2021] [Revised: 06/19/2021] [Accepted: 06/22/2021] [Indexed: 01/30/2023] Open
Abstract
In 30 monosubstituted benzene cation radicals, studied at the ωB97XD/aug-cc-pVTZ level, the phenyl rings usually adopt a compressed form, but a differently compressed form-equivalent to an elongated one-may coexist. The computational and literature ionization potentials are well correlated. The geometrical and magnetic aromaticity, estimated using HOMA and NICS indices, show the systems to be structurally aromatic but magnetically antiaromatic or only weakly aromatic. The partial charge is split between the substituent and ring and varies the most at C(ipso). In the ring, the spin is 70%, concentrated equally at the C(ipso) and C(p) atoms. The sEDA(D) and pEDA(D) descriptors of the substituent effect in cation radicals, respectively, were determined. In cation radicals, the substituent effect on the σ-electron system is like that in the ground state. The effect on the π-electron systems is long-range, and its propagation in the radical quinone-like ring is unlike that in the neutral molecules. The pEDA(D) descriptor correlates well with the partial spin at C(ipso) and C(p) and weakly with the HOMA(D) index. The correlation of the spin at the ring π-electron system and the pEDA(D) descriptor shows that the electron charge supplied to the ring π-electron system and the spin flow oppositely.
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Affiliation(s)
- Jan Cz. Dobrowolski
- National Medicines Institute, 00-725 Warsaw, Poland; (G.K.); (A.B.)
- Institute of Nuclear Chemistry and Technology, 03-195 Warsaw, Poland;
| | - Wojciech M. Dudek
- Institute of Nuclear Chemistry and Technology, 03-195 Warsaw, Poland;
| | | | - Anna Baraniak
- National Medicines Institute, 00-725 Warsaw, Poland; (G.K.); (A.B.)
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22
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Sharma K, Miller TA, Stanton JF. Vibronically coupled states: computational considerations and characterisation of vibronic and rovibronic spectroscopic parameters. INT REV PHYS CHEM 2021. [DOI: 10.1080/0144235x.2021.1874118] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Affiliation(s)
- Ketan Sharma
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH, USA
| | - Terry A. Miller
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH, USA
| | - John F. Stanton
- Department of Chemistry, University of Florida, Gainesville, FL, USA
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23
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Skomorowski W, Krylov AI. Feshbach-Fano approach for calculation of Auger decay rates using equation-of-motion coupled-cluster wave functions. I. Theory and implementation. J Chem Phys 2021; 154:084124. [PMID: 33639760 DOI: 10.1063/5.0036976] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
X-ray absorption creates electron vacancies in the core shell. These highly excited states often relax by Auger decay-an autoionization process in which one valence electron fills the core hole and another valence electron is ejected into the ionization continuum. Despite the important role of Auger processes in many experimental settings, their first-principles modeling is challenging, even for small systems. The difficulty stems from the need to describe many-electron continuum (unbound) states, which cannot be tackled with standard quantum-chemistry methods. We present a novel approach to calculate Auger decay rates by combining Feshbach-Fano resonance theory with the equation-of-motion coupled-cluster single double (EOM-CCSD) framework. We use the core-valence separation scheme to define projectors into the bound (square-integrable) and unbound (continuum) subspaces of the full function space. The continuum many-body decay states are represented by products of an appropriate EOM-CCSD state and a free-electron state, described by a continuum orbital. The Auger rates are expressed in terms of reduced quantities, two-body Dyson amplitudes (objects analogous to the two-particle transition density matrix), contracted with two-electron bound-continuum integrals. Here, we consider two approximate treatments of the free electron: a plane wave and a Coulomb wave with an effective charge, which allow us to evaluate all requisite integrals analytically; however, the theory can be extended to incorporate a more sophisticated description of the continuum orbital.
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Affiliation(s)
- Wojciech Skomorowski
- Department of Chemistry, University of Southern California, Los Angeles, California 90089, USA
| | - Anna I Krylov
- Department of Chemistry, University of Southern California, Los Angeles, California 90089, USA
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24
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Vidal ML, Epshtein M, Scutelnic V, Yang Z, Xue T, Leone SR, Krylov AI, Coriani S. Interplay of Open-Shell Spin-Coupling and Jahn-Teller Distortion in Benzene Radical Cation Probed by X-ray Spectroscopy. J Phys Chem A 2020; 124:9532-9541. [PMID: 33103904 DOI: 10.1021/acs.jpca.0c08732] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
We report a theoretical investigation and elucidation of the X-ray absorption spectra of neutral benzene and of the benzene cation. The generation of the cation by multiphoton ultraviolet (UV) ionization and the measurement of the carbon K-edge spectra of both species using a table-top high-harmonic generation source are described in the companion experimental paper [Epshtein, M.; et al. J. Phys. Chem. A http://dx.doi.org/10.1021/acs.jpca.0c08736]. We show that the 1sC → π transition serves as a sensitive signature of the transient cation formation, as it occurs outside of the spectral window of the parent neutral species. Moreover, the presence of the unpaired (spectator) electron in the π-subshell of the cation and the high symmetry of the system result in significant differences relative to neutral benzene in the spectral features associated with the 1sC → π* transitions. High-level calculations using equation-of-motion coupled-cluster theory provide the interpretation of the experimental spectra and insight into the electronic structure of benzene and its cation. The prominent split structure of the 1sC → π* band of the cation is attributed to the interplay between the coupling of the core → π* excitation with the unpaired electron in the π-subshell and the Jahn-Teller distortion. The calculations attribute most of the splitting (∼1-1.2 eV) to the spin coupling, which is visible already at the Franck-Condon structure, and we estimate the additional splitting due to structural relaxation to be around ∼0.1-0.2 eV. These results suggest that X-ray absorption with increased resolution might be able to disentangle electronic and structural aspects of the Jahn-Teller effect in the benzene cation.
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Affiliation(s)
- Marta L Vidal
- DTU Chemistry - Department of Chemistry, Technical University of Denmark, DK-2800, Kongens Lyngby, Denmark
| | - Michael Epshtein
- Department of Chemistry, University of California, Berkeley, California 94720, United States.,Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Valeriu Scutelnic
- Department of Chemistry, University of California, Berkeley, California 94720, United States
| | - Zheyue Yang
- Department of Chemistry, University of California, Berkeley, California 94720, United States
| | - Tian Xue
- Department of Chemistry, University of California, Berkeley, California 94720, United States
| | - Stephen R Leone
- Department of Chemistry, University of California, Berkeley, California 94720, United States.,Department of Physics, University of California, Berkeley, California 94720, United States
| | - Anna I Krylov
- Department of Chemistry, University of Southern California, Los Angeles, California 90089, United States
| | - Sonia Coriani
- DTU Chemistry - Department of Chemistry, Technical University of Denmark, DK-2800, Kongens Lyngby, Denmark
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