1
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Fouda AEA, Lindblom V, Southworth SH, Doumy G, Ho PJ, Young L, Cheng L, Sorensen SL. Influence of Selective Carbon 1s Excitation on Auger-Meitner Decay in the ESCA Molecule. J Phys Chem Lett 2024; 15:4286-4293. [PMID: 38608168 PMCID: PMC11057383 DOI: 10.1021/acs.jpclett.3c03611] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2023] [Revised: 03/22/2024] [Accepted: 04/04/2024] [Indexed: 04/14/2024]
Abstract
Two-dimensional spectral mapping is used to visualize how resonant Auger-Meitner spectra are influenced by the site of the initial core-electron excitation and the symmetry of the core-excited state in the trifluoroethyl acetate molecule (ESCA). We observe a significant enhancement of electron yield for excitation of the COO 1s → π* and CF3 1s → σ* resonances unlike excitation at resonances involving the CH3 and CH2 sites. The CF3 1s → π* and CF3 1s → σ* resonance spectra are very different from each other, with the latter populating most valence states equally. Two complementary electronic structure calculations for the photoelectron cross section and Auger-Meitner intensity are shown to effectively reproduce the site- and state-selective nature of the resonant enhancement features. The site of the core-electron excitation and the respective final state hole locality increase the sensistivity of the photoelectron signal at specific functional group sites. This showcases resonant Auger-Meitner decay as a potentially powerful tool for selectively probing structural changes at specific functional group sites of polyatomic molecules.
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Affiliation(s)
- A. E. A. Fouda
- Chemical
Sciences and Engineering Division, Argonne
National Laboratory, 9700 S. Cass Avenue, Lemont, Illinois 60439, United States
- Department
of Physics and James Franck Institute, The
University of Chicago, Chicago, Illinois 60637, United States
| | - V. Lindblom
- Department
of Physics, Lund University, Box 118, 22100 Lund, Sweden
| | - S. H. Southworth
- Chemical
Sciences and Engineering Division, Argonne
National Laboratory, 9700 S. Cass Avenue, Lemont, Illinois 60439, United States
| | - G. Doumy
- Chemical
Sciences and Engineering Division, Argonne
National Laboratory, 9700 S. Cass Avenue, Lemont, Illinois 60439, United States
| | - P. J. Ho
- Chemical
Sciences and Engineering Division, Argonne
National Laboratory, 9700 S. Cass Avenue, Lemont, Illinois 60439, United States
| | - L. Young
- Chemical
Sciences and Engineering Division, Argonne
National Laboratory, 9700 S. Cass Avenue, Lemont, Illinois 60439, United States
- Department
of Physics and James Franck Institute, The
University of Chicago, Chicago, Illinois 60637, United States
| | - L. Cheng
- Department
of Chemistry, Johns Hopkins University, 3400 North Charles St, Baltimore, Maryland 21218, United States
| | - S. L. Sorensen
- Department
of Physics, Lund University, Box 118, 22100 Lund, Sweden
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2
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Gerlach M, Schaffner D, Preitschopf T, Karaev E, Bozek J, Holzmeier F, Fischer I. X-ray induced fragmentation of fulminic acid, HCNO. J Chem Phys 2023; 159:114306. [PMID: 37721327 DOI: 10.1063/5.0167395] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2023] [Accepted: 08/24/2023] [Indexed: 09/19/2023] Open
Abstract
The fragmentation of fulminic acid, HCNO, after excitation and ionization of core electrons was investigated using Auger-electron-photoion coincidence spectroscopy. A considerable degree of site-selectivity is observed. Ionization of the carbon and oxygen 1s electron leads to around 70% CH+ + NO+, while ionization at the central N-atom produces only 37% CH+ + NO+, but preferentially forms O+ + HCN+ and O+ + CN+. The mass-selected Auger-electron spectra show that these fragments are associated with higher binding energy final states. Furthermore, ionization of the C 1s electron leads to a higher propensity for C-H bond fission compared to O 1s ionization. Following resonant Auger-Meitner decay after 1s → 3π excitation, 12 different ionic products are formed. At the C 1s edge, the parent ion HCNO+ is significantly more stable compared to the other two edges, which we also attribute to the higher contribution of final states with low binding energies in the C 1s resonant Auger electron spectra.
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Affiliation(s)
- Marius Gerlach
- Institute of Physical and Theoretical Chemistry, University of Würzburg, 97074 Würzburg, Germany
| | - Dorothee Schaffner
- Institute of Physical and Theoretical Chemistry, University of Würzburg, 97074 Würzburg, Germany
| | - Tobias Preitschopf
- Institute of Physical and Theoretical Chemistry, University of Würzburg, 97074 Würzburg, Germany
| | - Emil Karaev
- Institute of Physical and Theoretical Chemistry, University of Würzburg, 97074 Würzburg, Germany
| | - John Bozek
- Synchrotron SOLEIL, 91192 Gif-sur-Yvette, France
| | | | - Ingo Fischer
- Institute of Physical and Theoretical Chemistry, University of Würzburg, 97074 Würzburg, Germany
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3
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Matz F, Nijssen J, Jagau TC. Ab Initio Investigation of the Auger Spectra of Methane, Ethane, Ethylene, and Acetylene. J Phys Chem A 2023. [PMID: 37474285 DOI: 10.1021/acs.jpca.3c01649] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/22/2023]
Abstract
We present an ab initio computational study of the Auger spectra of methane, ethane, ethylene, and acetylene. Auger spectroscopy is an established technique to probe the electronic structure of molecules and exploits the Auger-Meitner effect that core-ionized states undergo. We compute partial decay widths using coupled-cluster theory with single and double substitutions (CCSD) and equation-of-motion CCSD theory combined with complex-scaled basis functions and Feshbach-Fano projection. We generate Auger spectra from these partial widths and draw conclusions about the strength of particular decay channels and trends among the four molecules. A connection to experimental results about fragmentation pathways of the electronic states produced by Auger decay is also made.
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Affiliation(s)
- Florian Matz
- Department of Chemistry, KU Leuven, B-3001 Leuven, Belgium
| | - Jonas Nijssen
- Department of Chemistry, KU Leuven, B-3001 Leuven, Belgium
| | - Thomas-C Jagau
- Department of Chemistry, KU Leuven, B-3001 Leuven, Belgium
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4
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Abid A, Veteläinen O, Boudjemia N, Pelimanni E, Kivimäki A, Alatalo M, Huttula M, Björneholm O, Patanen M. Forming Bonds While Breaking Old Ones: Isomer-Dependent Formation of H 3O + from Aminobenzoic Acid During X-ray-Induced Fragmentation. J Phys Chem A 2023; 127:1395-1401. [PMID: 36749682 PMCID: PMC9940210 DOI: 10.1021/acs.jpca.2c06869] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Intramolecular hydrogen transfer, a reaction where donor and acceptor sites of a hydrogen atom are part of the same molecule, is a ubiquitous reaction in biochemistry and organic synthesis. In this work, we report hydronium ion (H3O+) production from aminobenzoic acid (ABA) after core-level ionization with soft X-ray synchrotron radiation. The formation of H3O+ during the fragmentation requires that at least two hydrogen atoms migrate to one of the oxygen atoms within the molecule. The comparison of two structural isomers, ortho- and meta-ABA, revealed that the production of H3O+ depends strongly on the structure of the molecule, the ortho-isomer being much more prone to produce H3O+. The isomer-dependency suggests that the amine group acts as a donor in the hydrogen transfer process. In the case of ortho-ABA, detailed H3O+ production pathways were investigated using photoelectron-photoion-photoion coincidence (PEPIPICO) spectroscopy. It was found that H3O+ can result from a direct two-body dissociation but also from sequential fragmentation processes.
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Affiliation(s)
- Abdul
Rahman Abid
- Nano
and Molecular Systems Research Unit, University
of Oulu, 90570 Oulu, Finland,Molecular
and Condensed Matter Physics, Uppsala University, 75120 Uppsala, Sweden
| | - Onni Veteläinen
- Nano
and Molecular Systems Research Unit, University
of Oulu, 90570 Oulu, Finland
| | - Nacer Boudjemia
- Nano
and Molecular Systems Research Unit, University
of Oulu, 90570 Oulu, Finland
| | - Eetu Pelimanni
- Nano
and Molecular Systems Research Unit, University
of Oulu, 90570 Oulu, Finland
| | - Antti Kivimäki
- Nano
and Molecular Systems Research Unit, University
of Oulu, 90570 Oulu, Finland,MAX
IV Laboratory, Lund University, 22100 Lund, Sweden
| | - Matti Alatalo
- Nano
and Molecular Systems Research Unit, University
of Oulu, 90570 Oulu, Finland
| | - Marko Huttula
- Nano
and Molecular Systems Research Unit, University
of Oulu, 90570 Oulu, Finland
| | - Olle Björneholm
- Molecular
and Condensed Matter Physics, Uppsala University, 75120 Uppsala, Sweden
| | - Minna Patanen
- Nano
and Molecular Systems Research Unit, University
of Oulu, 90570 Oulu, Finland,
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5
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Krupa J, Wierzejewska M, Lundell J. Experimental FTIR-MI and Theoretical Studies of Isocyanic Acid Aggregates. Molecules 2023; 28:molecules28031430. [PMID: 36771094 PMCID: PMC9921473 DOI: 10.3390/molecules28031430] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2023] [Revised: 01/29/2023] [Accepted: 01/31/2023] [Indexed: 02/05/2023] Open
Abstract
Homoaggregates of isocyanic acid (HNCO) were studied using FTIR spectroscopy combined with a low-temperature matrix isolation technique and quantum chemical calculations. Computationally, the structures of the HNCO dimers and trimers were optimized at the MP2, B3LYPD3 and B2PLYPD3 levels of theory employing the 6-311++G(3df,3pd) basis set. Topological analysis of the electron density (AIM) was used to identify the type of non-covalent interactions in the studied aggregates. Five stable minima were located on the potential energy surface for (HNCO)2, and nine were located on the potential energy surface for (HNCO)3. The most stable dimer (D1) involves a weak, almost linear N-H⋯N hydrogen bond. Other structures are bound by a N-H⋯O hydrogen bond or by O⋯C or N⋯N van der Waals interactions. Similar types of interactions as in (HNCO)2 were found in the case of HNCO trimers. Among nine stable (HNCO)3 structures, five represent cyclic forms. The most stable T1 trimer structure is characterized by a six-membered ring formed by three N-H⋯N hydrogen bonds and representing high symmetry (C3h). The analysis of the HNCO/Ar spectra after deposition indicates that the N-H⋯O hydrogen-bonded dimers are especially prevalent. Upon annealing, HNCO trimers were observed as well. Identification of the experimentally observed species relied on previous experimental data on HNCO complexes as well as computed data on HNCO homoaggregates' vibrational spectra.
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Affiliation(s)
- Justyna Krupa
- Faculty of Chemistry, University of Wrocław, F. Joliot-Curie 14, 50-383 Wrocław, Poland
- Correspondence: (J.K.); (J.L.); Tel.: +358-40-744-5270 (J.L.)
| | - Maria Wierzejewska
- Faculty of Chemistry, University of Wrocław, F. Joliot-Curie 14, 50-383 Wrocław, Poland
| | - Jan Lundell
- Department of Chemistry, University of Jyväskylä, FI-40014 Jyväskylä, Finland
- Correspondence: (J.K.); (J.L.); Tel.: +358-40-744-5270 (J.L.)
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6
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Gerlach M, Preitschopf T, Karaev E, Quitián-Lara HM, Mayer D, Bozek J, Fischer I, Fink RF. Auger electron spectroscopy of fulminic acid, HCNO: an experimental and theoretical study. Phys Chem Chem Phys 2022; 24:15217-15229. [PMID: 35703845 DOI: 10.1039/d2cp02104h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
HCNO is a molecule of considerable astrochemical interest as a precursor to prebiotic molecules. It is synthesized by preparative pyrolysis and is unstable at room temperature. Here, we investigate its spectroscopy in the soft X-ray regime at the C 1s, N 1s and O 1s edges. All 1s ionization energies are reported and X-ray absorption spectra reveal the transitions from the 1s to the π* state. Resonant and normal Auger electron spectra for the decay of the core hole states are recorded in a hemispherical analyzer. An assignment of the experimental spectra is provided with the aid of theoretical counterparts. The latter are using a valence configuration interaction representation of the intermediate and final state energies and wavefunctions, the one-center approximation for transition rates and band shapes according to the moment theory. The computed spectra are in very good agreement with the experimental data and most of the relevant bands are assigned. Additionally, we present a simple approach to estimate relative Auger transition rates on the basis of a minimal basis representation of the molecular orbitals. We demonstrate that this provides a qualitatively good and reliable estimate for several signals in the normal and resonant Auger electron spectra which have significantly different intensities in the decay of the three core holes.
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Affiliation(s)
- Marius Gerlach
- Institute of Physical and Theoretical Chemistry, University of Würzburg, 97074 Würzburg, Germany.
| | - Tobias Preitschopf
- Institute of Physical and Theoretical Chemistry, University of Würzburg, 97074 Würzburg, Germany.
| | - Emil Karaev
- Institute of Physical and Theoretical Chemistry, University of Würzburg, 97074 Würzburg, Germany.
| | - Heidy M Quitián-Lara
- Institute of Physical and Theoretical Chemistry, University of Würzburg, 97074 Würzburg, Germany.
| | - Dennis Mayer
- Institut für Physik und Astronomie, Universität Potsdam, Karl-Liebknecht-Straße 24/25, 14476 Potsdam-Golm, Germany
| | - John Bozek
- Synchrotron SOLEIL, L'Orme des Merisiers, 91192 Gif-sur-Yvette, France
| | - Ingo Fischer
- Institute of Physical and Theoretical Chemistry, University of Würzburg, 97074 Würzburg, Germany.
| | - Reinhold F Fink
- Institut für Physikalische und Theoretische Chemie, Universität Tübingen, Auf der Morgenstelle 18, 72076 Tübingen, Germany.
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7
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Tenorio BNC, Voß TA, Bokarev SI, Decleva P, Coriani S. Multireference Approach to Normal and Resonant Auger Spectra Based on the One-Center Approximation. J Chem Theory Comput 2022; 18:4387-4407. [PMID: 35737643 PMCID: PMC9281372 DOI: 10.1021/acs.jctc.2c00252] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A methodology to calculate the decay rates of normal and resonant Auger processes in atoms and molecules based on the One-Center Approximation (OCA), using atomic radial Auger integrals, is implemented within the restricted-active-space self-consistent-field (RASSCF) and the multistate restricted-active-space perturbation theory of second order (MS-RASPT2) frameworks, as part of the OpenMolcas project. To ensure an unbiased description of the correlation and relaxation effects on the initial core excited/ionized states and the final cationic states, their wave functions are optimized independently, whereas the Auger matrix elements are computed with a biorthonormalized set of molecular orbitals within the state-interaction (SI) approach. As a decay of an isolated resonance, the computation of Auger intensities involves matrix elements with one electron in the continuum. However, treating ionization and autoionization problems can be overwhelmingly complicated for nonexperts, because of many peculiarities, in comparison to bound-state electronic structure theory. One of the advantages of our approach is that by projecting the intensities on the atomic center bearing the core hole and using precalculated atomic radial two-electron integrals, the Auger decay rates can be easily obtained directly with OpenMolcas, avoiding the need to interface it with external programs to compute matrix elements with the photoelectron wave function. The implementation is tested on the Ne atom, for which numerous theoretical and experimental results are available for comparison, as well as on a set of prototype closed- and open-shell molecules, namely, CO, N2, HNCO, H2O, NO2, and C4N2H4 (pyrimidine).
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Affiliation(s)
- Bruno Nunes Cabral Tenorio
- DTU Chemistry - Department of Chemistry, Technical University of Denmark, Kemitorvet Bldg 207, DK-2800 Kongens Lyngby, Denmark
| | - Torben Arne Voß
- Institut für Physik, Universität Rostock, Albert-Einstein-Str. 23-24, D-18059 Rostock, Germany
| | - Sergey I Bokarev
- Institut für Physik, Universität Rostock, Albert-Einstein-Str. 23-24, D-18059 Rostock, Germany
| | - Piero Decleva
- Istituto Officina dei Materiali IOM-CNR and Dipartimento di Scienze Chimiche e Farmaceutiche, Università degli Studi di Trieste, I-34121 Trieste, Italy
| | - Sonia Coriani
- DTU Chemistry - Department of Chemistry, Technical University of Denmark, Kemitorvet Bldg 207, DK-2800 Kongens Lyngby, Denmark.,Department of Chemistry, Norwegian University of Science and Technology, N-7491 Trondheim, Norway
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8
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Matrix Isolation FTIR and Theoretical Study of Weakly Bound Complexes of Isocyanic Acid with Nitrogen. MOLECULES (BASEL, SWITZERLAND) 2022; 27:molecules27020495. [PMID: 35056808 PMCID: PMC8777744 DOI: 10.3390/molecules27020495] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/20/2021] [Revised: 01/09/2022] [Accepted: 01/11/2022] [Indexed: 11/17/2022]
Abstract
Weak complexes of isocyanic acid (HNCO) with nitrogen were studied computationally employing MP2, B2PLYPD3 and B3LYPD3 methods and experimentally by FTIR matrix isolation technique. The results show that HNCO interacts specifically with N2. For the 1:1 stoichiometry, three stable minima were located on the potential energy surface. The most stable of them involves a weak, almost linear hydrogen bond from the NH group of the acid molecule to nitrogen molecule lone pair. Two other structures are bound by van der Waals interactions of N⋯N and C⋯N types. The 1:2 and 2:1 HNCO complexes with nitrogen were computationally tracked as well. Similar types of interactions as in the 1:1 complexes were found in the case of the higher stoichiometry complexes. Analysis of the HNCO/N2/Ar spectra after deposition indicates that the 1:1 hydrogen-bonded complex is prevalent in argon matrices with a small amount of the van der Waals structures also present. Upon annealing, complexes of the 1:2 and 2:1 stoichiometry were detected as well.
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9
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Seymour J, Gousseva E, Large A, Held G, Hein D, Wartner G, Quevedo W, Seidel R, Kolbeck C, Clarke CJ, Fogarty R, Bourne R, Bennett R, Palgrave R, Hunt PA, Lovelock KRJ. Resonant Electron Spectroscopy: Identification of Atomic Contributions to Valence States. Faraday Discuss 2022; 236:389-411. [DOI: 10.1039/d1fd00117e] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Valence electronic structure is crucial for understanding and predicting reactivity. Valence non-resonant X-ray photoelectron spectroscopy (NRXPS) provides a direct method for probing the overall valence electronic structure. However, it is...
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10
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Core-Level Spectroscopy of 2-Thiouracil at the Sulfur L 1- and L 2,3-Edges Utilizing a SASE Free-Electron Laser. Molecules 2021; 26:molecules26216469. [PMID: 34770877 PMCID: PMC8586990 DOI: 10.3390/molecules26216469] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2021] [Revised: 10/21/2021] [Accepted: 10/22/2021] [Indexed: 11/17/2022] Open
Abstract
In this paper, we report X-ray absorption and core-level electron spectra of the nucleobase derivative 2-thiouracil at the sulfur L1- and L2,3-edges. We used soft X-rays from the free-electron laser FLASH2 for the excitation of isolated molecules and dispersed the outgoing electrons with a magnetic bottle spectrometer. We identified photoelectrons from the 2p core orbital, accompanied by an electron correlation satellite, as well as resonant and non-resonant Coster–Kronig and Auger–Meitner emission at the L1- and L2,3-edges, respectively. We used the electron yield to construct X-ray absorption spectra at the two edges. The experimental data obtained are put in the context of the literature currently available on sulfur core-level and 2-thiouracil spectroscopy.
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11
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Krupa J, Wierzejewska M, Lundell J. Structure and IR Spectroscopic Properties of HNCO Complexes with SO 2 Isolated in Solid Argon. Molecules 2021; 26:molecules26216441. [PMID: 34770850 PMCID: PMC8587861 DOI: 10.3390/molecules26216441] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2021] [Revised: 10/13/2021] [Accepted: 10/22/2021] [Indexed: 11/16/2022] Open
Abstract
FTIR spectroscopy was combined with the matrix isolation technique and quantum chemical calculations with the aim of studying complexes of isocyanic acid with sulfur dioxide. The structures of the HNCO⋯SO2 complexes of 1:1, 1:2 and 2:1 stoichiometry were optimized at the MP2, B3LYPD3, B2PLYPD3 levels of theory with the 6-311++G(3df,3pd) basis set. Five stable 1:1 HNCO⋯SO2 complexes were found. Three of them contain a weak N-H⋯O hydrogen bond, whereas two other structures are stabilized by van der Waals interactions. The analysis of the HNCO/SO2/Ar spectra after deposition indicates that mostly the 1:1 hydrogen-bonded complexes are present in argon matrices, with a small amount of the van der Waals structures. Upon annealing, complexes of the 1:2 stoichiometry were detected, as well.
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Affiliation(s)
- Justyna Krupa
- Faculty of Chemistry, University of Wroclaw, Joliot-Curie 14, 50-383 Wroclaw, Poland;
- Correspondence: (J.K.); (J.L.); Tel.: +358-40-744-5270 (J.L.)
| | - Maria Wierzejewska
- Faculty of Chemistry, University of Wroclaw, Joliot-Curie 14, 50-383 Wroclaw, Poland;
| | - Jan Lundell
- Department of Chemistry, University of Jyväskylä, P.O. Box 35, FI-40014 Jyväskylä, Finland
- Correspondence: (J.K.); (J.L.); Tel.: +358-40-744-5270 (J.L.)
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12
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Wolf TJA, Paul AC, Folkestad SD, Myhre RH, Cryan JP, Berrah N, Bucksbaum PH, Coriani S, Coslovich G, Feifel R, Martinez TJ, Moeller SP, Mucke M, Obaid R, Plekan O, Squibb RJ, Koch H, Gühr M. Transient resonant Auger-Meitner spectra of photoexcited thymine. Faraday Discuss 2021; 228:555-570. [PMID: 33566045 DOI: 10.1039/d0fd00112k] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We present the first investigation of excited state dynamics by resonant Auger-Meitner spectroscopy (also known as resonant Auger spectroscopy) using the nucleobase thymine as an example. Thymine is photoexcited in the UV and probed with X-ray photon energies at and below the oxygen K-edge. After initial photoexcitation to a ππ* excited state, thymine is known to undergo internal conversion to an nπ* excited state with a strong resonance at the oxygen K-edge, red-shifted from the ground state π* resonances of thymine (see our previous study Wolf, et al., Nat. Commun., 2017, 8, 29). We resolve and compare the Auger-Meitner electron spectra associated both with the excited state and ground state resonances, and distinguish participator and spectator decay contributions. Furthermore, we observe simultaneously with the decay of the nπ* state signatures the appearance of additional resonant Auger-Meitner contributions at photon energies between the nπ* state and the ground state resonances. We assign these contributions to population transfer from the nπ* state to a ππ* triplet state via intersystem crossing on the picosecond timescale based on simulations of the X-ray absorption spectra in the vibrationally hot triplet state. Moreover, we identify signatures from the initially excited ππ* singlet state which we have not observed in our previous study.
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Affiliation(s)
- Thomas J A Wolf
- Stanford PULSE Institute, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA 94025, USA.
| | - Alexander C Paul
- Department of Chemistry, Norwegian University of Science and Technology, NO-7491 Trondheim, Norway
| | - Sarai D Folkestad
- Department of Chemistry, Norwegian University of Science and Technology, NO-7491 Trondheim, Norway
| | - Rolf H Myhre
- Department of Chemistry, Norwegian University of Science and Technology, NO-7491 Trondheim, Norway
| | - James P Cryan
- Stanford PULSE Institute, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA 94025, USA.
| | - Nora Berrah
- Department of Physics, University of Connecticut Storrs, 2152 Hillside Road, Storrs, CT 06269, USA
| | - Phil H Bucksbaum
- Stanford PULSE Institute, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA 94025, USA. and Departments of Physics and Applied Physics, Stanford University, 382 Via Pueblo Mall, Stanford, CA 94305, USA
| | - Sonia Coriani
- Department of Chemistry, Norwegian University of Science and Technology, NO-7491 Trondheim, Norway and DTU Chemistry, Technical University of Denmark, Kongens Lyngby, DK-2800, Denmark
| | - Giacomo Coslovich
- Linac Coherent Lightsource, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA 94025, USA
| | - Raimund Feifel
- Department of Physics, University of Gothenburg, Origovägen 6B, 412 58 Gothenburg, Sweden
| | - Todd J Martinez
- Stanford PULSE Institute, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA 94025, USA. and Department of Chemistry, Stanford University, 333 Campus Drive, Stanford, CA 94305, USA
| | - Stefan P Moeller
- Linac Coherent Lightsource, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA 94025, USA
| | - Melanie Mucke
- Department of Physics and Astronomy, Uppsala University, Uppsala, Sweden
| | - Razib Obaid
- Department of Physics, University of Connecticut Storrs, 2152 Hillside Road, Storrs, CT 06269, USA
| | - Oksana Plekan
- Elettra-Sincrotrone Trieste, 34149 Basovizza, Trieste, Italy
| | - Richard J Squibb
- Department of Physics, University of Gothenburg, Origovägen 6B, 412 58 Gothenburg, Sweden
| | - Henrik Koch
- Scuola Normale Superiore, I-56126 Pisa, Italy.
| | - Markus Gühr
- Institut für Physik und Astronomie, Universität Potsdam, Karl-Liebknecht-Straßze 24/25, DE-14476 Potsdam, Germany.
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13
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Gerlach M, Fantuzzi F, Wohlfart L, Kopp K, Engels B, Bozek J, Nicolas C, Mayer D, Gühr M, Holzmeier F, Fischer I. Fragmentation of isocyanic acid, HNCO, following core excitation and ionization. J Chem Phys 2021; 154:114302. [PMID: 33752348 DOI: 10.1063/5.0044506] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
We report a study on the fragmentation of core-ionized and core-excited isocyanic acid, HNCO, using Auger-electron/photoion coincidence spectroscopy. Site-selectivity is observed both for normal and resonant Auger electron decay. Oxygen 1s ionization leads to the CO+ + NH+ ion pairs, while nitrogen 1s ionization results in three-body dissociation and an efficient fragmentation of the H-N bond in the dication. Upon 1s → 10a' resonant excitation, clear differences between O and N sites are discernible as well. In both cases, the correlation between the dissociation channel and the binding energy of the normal Auger electrons indicates that the fragmentation pattern is governed by the excess energy available in the final ionic state. High-level multireference calculations suggest pathways to the formation of the fragment ions NO+ and HCO+, which are observed although the parent compound contains neither N-O nor H-C bonds. This work contributes to the goal to achieve and understand site-selective fragmentation upon ionization and excitation of molecules with soft x-ray radiation.
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Affiliation(s)
- Marius Gerlach
- Institute of Physical and Theoretical Chemistry, University of Würzburg, 97074 Würzburg, Germany
| | - Felipe Fantuzzi
- Institute of Physical and Theoretical Chemistry, University of Würzburg, 97074 Würzburg, Germany
| | - Lilith Wohlfart
- Institute of Physical and Theoretical Chemistry, University of Würzburg, 97074 Würzburg, Germany
| | - Karina Kopp
- Institute of Physical and Theoretical Chemistry, University of Würzburg, 97074 Würzburg, Germany
| | - Bernd Engels
- Institute of Physical and Theoretical Chemistry, University of Würzburg, 97074 Würzburg, Germany
| | - John Bozek
- Synchrotron SOLEIL, 91192 Gif-sur-Yvette, France
| | | | - Dennis Mayer
- Institut für Physik und Astronomie, Universität Potsdam, 14476 Potsdam-Golm, Germany
| | - Markus Gühr
- Institut für Physik und Astronomie, Universität Potsdam, 14476 Potsdam-Golm, Germany
| | - Fabian Holzmeier
- Dipartimento di Fisica, Politecnico di Milano, 20133 Milano, Italy
| | - Ingo Fischer
- Institute of Physical and Theoretical Chemistry, University of Würzburg, 97074 Würzburg, Germany
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Grell G, Bokarev SI. Multi-reference protocol for (auto)ionization spectra: Application to molecules. J Chem Phys 2020; 152:074108. [DOI: 10.1063/1.5142251] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Gilbert Grell
- Institut für Physik, Universität Rostock, Albert-Einstein-Str. 23-24, 18059 Rostock, Germany
| | - Sergey I. Bokarev
- Institut für Physik, Universität Rostock, Albert-Einstein-Str. 23-24, 18059 Rostock, Germany
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Abstract
Double and triple ionisation spectra of the reactive molecule isocyanic acid (HNCO) have been measured using multi-electron and ion coincidence techniques combined with synchrotron radiation and compared with high-level theoretical calculations. Vertical double ionisation at an energy of 32.8 ± 0.3 eV forms the 3A" ground state in which the HNCO2+ ion is long lived. The vertical triple ionisation energy is determined as 65 ± 1 eV. The core-valence double ionisation spectra resemble the valence photoelectron spectrum in form, and their main features can be understood on the basis of a simple and rather widely applicable Coulomb model based on the characteristics of the molecular orbitals from which electrons are removed. Characteristics of the most important dissociation channels are examined and discussed.
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Wolf TJA, Gühr M. Photochemical pathways in nucleobases measured with an X-ray FEL. PHILOSOPHICAL TRANSACTIONS. SERIES A, MATHEMATICAL, PHYSICAL, AND ENGINEERING SCIENCES 2019; 377:20170473. [PMID: 30929626 PMCID: PMC6452046 DOI: 10.1098/rsta.2017.0473] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
The conversion of light energy into other molecular energetic degrees of freedom is often dominated by ultrafast, non-adiabatic processes. Femtosecond spectroscopy with optical pulses has helped in shaping our understanding of crucial processes in molecular energy-conversion. The advent of new, ultrashort and bright X-ray free electron laser sources opens the possibility to use X-ray-typical element and site sensitivity for ultrafast molecular research. We present two types of spectroscopy, ultrafast Auger and ultrafast X-ray absorption spectroscopy, and discuss their sensitivity to molecular processes. While Auger spectroscopy is able to monitor bond distance changes in the vicinity of an X-ray created core hole, near-edge absorption spectroscopy can deliver high-fidelity information on non-adiabatic transitions involving lone-pair orbitals. We demonstrate these features on the example of the UV-excited nucleobase thymine, investigated at the oxygen K-edge. We find a C-O bond elongation in the Auger data in addition to ππ*/ nπ* non-adiabatic transition in X-ray near-edge absorption. We compare the results from both methods and draw a conclusive scenario of non-adiabatic molecular relaxation after UV excitation. This article is part of the theme issue 'Measurement of ultrafast electronic and structural dynamics with X-rays'.
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Affiliation(s)
- Thomas J. A. Wolf
- SLAC National Accelerator Laboratory, PULSE, 2575 Sand Hill Road, Menlo Park 94025, CA, USA
| | - Markus Gühr
- SLAC National Accelerator Laboratory, PULSE, 2575 Sand Hill Road, Menlo Park 94025, CA, USA
- Physics and Astronomy Institute, Universität Potsdam, Karl-Liebknecht-Strasse 24/25, Potsdam 14476, Germany
- e-mail:
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