1
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Pflüger M, Brunner D, Heuser T, Lott JA, Reitzenstein S, Fischer I. Experimental reservoir computing with diffractively coupled VCSELs. Opt Lett 2024; 49:2285-2288. [PMID: 38691700 DOI: 10.1364/ol.518946] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/02/2024] [Accepted: 03/19/2024] [Indexed: 05/03/2024]
Abstract
We present experiments on reservoir computing (RC) using a network of vertical-cavity surface-emitting lasers (VCSELs) that we diffractively couple via an external cavity. Our optical reservoir computer consists of 24 physical VCSEL nodes. We evaluate the system's memory and solve the 2-bit XOR task and the 3-bit header recognition (HR) task with bit error ratios (BERs) below 1% and the 2-bit digital-to-analog conversion (DAC) task with a root mean square error (RMSE) of 0.067.
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2
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Sturm F, Bühler M, Stapper C, Schneider JS, Helten H, Fischer I, Röhr MIS. Impact of isoelectronic substitution on the excited state processes in polycyclic aromatic hydrocarbons: a joint experimental and theoretical study of 4 a,8 a-azaboranaphthalene. Phys Chem Chem Phys 2024; 26:7363-7370. [PMID: 38375909 DOI: 10.1039/d3cp05508f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/21/2024]
Abstract
Substituting CC with the isoelectronic BN units is a promising approach to modify the optoelectronic properties of polycyclic aromatic hydrocarbons. While computational studies have already addressed trends in the electronic structure of the various isosteres, experimental data are still scarce. Here, the excited state spectroscopy and dynamics of 4a,8a-azaboranaphthalene were studied by picosecond time-resolved photoionization in a supersonic jet and analyzed with the aid of XMS-CASPT2 and time-dependent DFT calculations. A resonance-enhanced multiphoton ionization spectrum (REMPI) reveals the S1 origin at = 33 830 ± 12 cm-1. Several vibrational bands were resolved and assigned by comparison with the computations. A [1+1] photoelectron spectrum via the S1 origin yielded an adiabatic ionization energy of 8.27 eV. Selected vibrational bands were subsequently investigated by pump-probe photoionization. While the origin as well as several low-lying vibronic states exhibit lifetimes in the ns-range, a monoexponential decay is observed at higher excitation energies, ranging from 400 ps at +1710 cm-1 to 13 ps at +3360 cm-1. The deactivation is attributed to an internal conversion of the optically excited S1 state via a barrier that gives access to a conical intersection (CI) to the S0 state. The doping significantly changes the energetic ordering of CIs and lowers the corresponding energy barrier for the associated deactivation pathway, as revealed by nudged elastic band (NEB) calculations.
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Affiliation(s)
- Floriane Sturm
- Institute of Physical and Theoretical Chemistry, University of Würzburg, Am Hubland, 97074 Würzburg, Germany.
| | - Michael Bühler
- Institute of Physical and Theoretical Chemistry, University of Würzburg, Am Hubland, 97074 Würzburg, Germany.
| | - Christoph Stapper
- Institute of Physical and Theoretical Chemistry, University of Würzburg, Am Hubland, 97074 Würzburg, Germany.
| | - Johannes S Schneider
- Institute of Inorganic Chemistry and Institute for Sustainable Chemistry & Catalysis with Boron (ICB), University of Würzburg, Am Hubland, 97074 Würzburg, Germany.
| | - Holger Helten
- Institute of Inorganic Chemistry and Institute for Sustainable Chemistry & Catalysis with Boron (ICB), University of Würzburg, Am Hubland, 97074 Würzburg, Germany.
| | - Ingo Fischer
- Institute of Physical and Theoretical Chemistry, University of Würzburg, Am Hubland, 97074 Würzburg, Germany.
| | - Merle I S Röhr
- Institute of Physical and Theoretical Chemistry, University of Würzburg, Am Hubland, 97074 Würzburg, Germany.
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3
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Sturm F, Philipp LN, Flock M, Fischer I, Mitric R. The Electronic Structures of Azaphenanthrenes and Their Dimers. J Phys Chem A 2024; 128:1250-1259. [PMID: 38345912 DOI: 10.1021/acs.jpca.3c07740] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/23/2024]
Abstract
Insertion of a nitrogen atom modifies the electronic structures and photochemistry of polycyclic aromatic hydrocarbons by introducing nπ* states into the molecules. To better understand the electronic structures of isolated polycyclic aromatic nitrogen-containing hydrocarbons (PANHs) and their dimers as well as the influence of the position of the nitrogen atom in the molecule, we investigate three different azaphenanthrenes, benzo[f]quinoline, benzo[h]quinoline, and phenanthridine, in a joint experimental and computational study. Experimentally, resonance-enhanced multiphoton ionization (REMPI) spectroscopy is applied to characterize the excited electronic states. The REMPI spectra of the azaphenanthrene monomers have a rather similar appearance, with origins between 3.645 and 3.670 eV for the 1ππ* ← S0 transition. In contrast to the phenanthrene parent, 2ππ* ← S0 is broad and unstructured even at the band origin. The experiments are accompanied by density functional theory computation, and vibrationally resolved spectra are simulated using a time-independent approach. The differences between phenanthrene and the azaphenanthrenes are assigned to perturbations due to the low-lying 1(nπ*) state, which accelerates nonradiative deactivation. For the dimers, it is found that two π-stacked isomers with two electronic transitions each contribute to the electronic spectrum, leading to overlapping bands that are difficult to assign.
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Affiliation(s)
- F Sturm
- Institute of Physical and Theoretical Chemistry, University of Würzburg, Am Hubland, Würzburg D-97074, Germany
| | - L N Philipp
- Institute of Physical and Theoretical Chemistry, University of Würzburg, Am Hubland, Würzburg D-97074, Germany
| | - M Flock
- Institute of Physical and Theoretical Chemistry, University of Würzburg, Am Hubland, Würzburg D-97074, Germany
| | - I Fischer
- Institute of Physical and Theoretical Chemistry, University of Würzburg, Am Hubland, Würzburg D-97074, Germany
| | - R Mitric
- Institute of Physical and Theoretical Chemistry, University of Würzburg, Am Hubland, Würzburg D-97074, Germany
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4
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Knuplez T, Schneider LN, Preitschopf T, Bejaoui YKJ, Zapf L, Schopper N, Maibom KAM, Sprenger JAP, Gehrke F, Lorenzen S, Graf R, Bertermann R, Fischer I, Ignat'ev NV, Finze M. Synthesis of Partially Fluorinated Alkyl Triflates by Electrochemical Fluorination (Simons Process). Chemistry 2023; 29:e202302701. [PMID: 37615512 DOI: 10.1002/chem.202302701] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2023] [Revised: 08/24/2023] [Accepted: 08/24/2023] [Indexed: 08/25/2023]
Abstract
A scalable straightforward synthesis of monofluoro- and difluoromethyl triflate CF3 SO2 OCH2 F (MH2F ) and CF3 SO2 OCHF2 (MHF2 ) through electrochemical fluorination (ECF, Simons process) of methyl triflate MH3 in anhydrous hydrogen fluoride at nickel anodes is presented. The ECF method is also feasible for the preparation of the deuterated analogues CF3 SO2 OCD2 F (MD2F ) and CF3 SO2 OCDF2 (MD2F ). Surprisingly, no H/D exchange occurs during ECF of CF3 SO2 OCD3 (MD3 ); this provides further evidence for a NiF3 /NiF4 -mediated ECF mechanism. The ECF of selected partially fluorinated ethyl triflates is described, and electrochemical fluorination of CF3 SO2 OCH2 CF3 (EH2F3 ) leads to the until now unknown chiral CF3 SO2 OCHFCF3 (EHFF3 ). The analogous fluoromethyl and fluoroethyl nonaflates are also accessible by ECF. This study contains detailed spectroscopic, structural, and thermal data on (fluoro)methyl and fluoro(ethyl) triflates.
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Affiliation(s)
- Tanja Knuplez
- Institut für nachhaltige Chemie & Katalyse mit Bor (ICB) Institut für Anorganische Chemie, Julius-Maximimilians-Universität Würzburg, Am Hubland, 97074, Würzburg, Germany
| | - Leon N Schneider
- Institut für nachhaltige Chemie & Katalyse mit Bor (ICB) Institut für Anorganische Chemie, Julius-Maximimilians-Universität Würzburg, Am Hubland, 97074, Würzburg, Germany
| | - Tobias Preitschopf
- Institut für nachhaltige Chemie & Katalyse mit Bor (ICB) Institut für Anorganische Chemie, Julius-Maximimilians-Universität Würzburg, Am Hubland, 97074, Würzburg, Germany
| | - Younes K J Bejaoui
- Institut für nachhaltige Chemie & Katalyse mit Bor (ICB) Institut für Anorganische Chemie, Julius-Maximimilians-Universität Würzburg, Am Hubland, 97074, Würzburg, Germany
| | - Ludwig Zapf
- Institut für nachhaltige Chemie & Katalyse mit Bor (ICB) Institut für Anorganische Chemie, Julius-Maximimilians-Universität Würzburg, Am Hubland, 97074, Würzburg, Germany
| | - Nils Schopper
- Institut für nachhaltige Chemie & Katalyse mit Bor (ICB) Institut für Anorganische Chemie, Julius-Maximimilians-Universität Würzburg, Am Hubland, 97074, Würzburg, Germany
| | - Kristina A M Maibom
- Institut für nachhaltige Chemie & Katalyse mit Bor (ICB) Institut für Anorganische Chemie, Julius-Maximimilians-Universität Würzburg, Am Hubland, 97074, Würzburg, Germany
| | - Jan A P Sprenger
- Institut für nachhaltige Chemie & Katalyse mit Bor (ICB) Institut für Anorganische Chemie, Julius-Maximimilians-Universität Würzburg, Am Hubland, 97074, Würzburg, Germany
| | - Franziska Gehrke
- Institut für nachhaltige Chemie & Katalyse mit Bor (ICB) Institut für Anorganische Chemie, Julius-Maximimilians-Universität Würzburg, Am Hubland, 97074, Würzburg, Germany
| | - Sabine Lorenzen
- Institut für nachhaltige Chemie & Katalyse mit Bor (ICB) Institut für Anorganische Chemie, Julius-Maximimilians-Universität Würzburg, Am Hubland, 97074, Würzburg, Germany
| | - Roland Graf
- Institut für nachhaltige Chemie & Katalyse mit Bor (ICB) Institut für Anorganische Chemie, Julius-Maximimilians-Universität Würzburg, Am Hubland, 97074, Würzburg, Germany
| | - Rüdiger Bertermann
- Institut für nachhaltige Chemie & Katalyse mit Bor (ICB) Institut für Anorganische Chemie, Julius-Maximimilians-Universität Würzburg, Am Hubland, 97074, Würzburg, Germany
| | - Ingo Fischer
- Institut für Physikalische Chemie, Julius-Maximimilians-Universität Würzburg, Am Hubland, 97074, Würzburg, Germany
| | - Nikolai V Ignat'ev
- Institut für nachhaltige Chemie & Katalyse mit Bor (ICB) Institut für Anorganische Chemie, Julius-Maximimilians-Universität Würzburg, Am Hubland, 97074, Würzburg, Germany
- Consultant, Merck Life Science KGaA, 64293, Darmstadt, Germany
| | - Maik Finze
- Institut für nachhaltige Chemie & Katalyse mit Bor (ICB) Institut für Anorganische Chemie, Julius-Maximimilians-Universität Würzburg, Am Hubland, 97074, Würzburg, Germany
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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] [What about the content of this article? (0)] [Affiliation(s)] [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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6
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Goldmann M, Fischer I, Mirasso CR, C Soriano M. Exploiting oscillatory dynamics of delay systems for reservoir computing. Chaos 2023; 33:093139. [PMID: 37748487 DOI: 10.1063/5.0156494] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/30/2023] [Accepted: 09/05/2023] [Indexed: 09/27/2023]
Abstract
Nonlinear dynamical systems exhibiting inherent memory can process temporal information by exploiting their responses to input drives. Reservoir computing is a prominent approach to leverage this ability for time-series forecasting. The computational capabilities of analog computing systems often depend on both the dynamical regime of the system and the input drive. Most studies have focused on systems exhibiting a stable fixed-point solution in the absence of input. Here, we go beyond that limitation, investigating the computational capabilities of a paradigmatic delay system in three different dynamical regimes. The system we chose has an Ikeda-type nonlinearity and exhibits fixed point, bistable, and limit-cycle dynamics in the absence of input. When driving the system, new input-driven dynamics emerge from the autonomous ones featuring characteristic properties. Here, we show that it is feasible to attain consistent responses across all three regimes, which is an essential prerequisite for the successful execution of the tasks. Furthermore, we demonstrate that we can exploit all three regimes in two time-series forecasting tasks, showcasing the versatility of this paradigmatic delay system in an analog computing context. In all tasks, the lowest prediction errors were obtained in the regime that exhibits limit-cycle dynamics in the undriven reservoir. To gain further insights, we analyzed the diverse time-distributed node responses generated in the three regimes of the undriven system. An increase in the effective dimensionality of the reservoir response is shown to affect the prediction error, as also fine-tuning of the distribution of nonlinear responses. Finally, we demonstrate that a trade-off between prediction accuracy and computational speed is possible in our continuous delay systems. Our results not only provide valuable insights into the computational capabilities of complex dynamical systems but also open a new perspective on enhancing the potential of analog computing systems implemented on various hardware platforms.
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Affiliation(s)
- Mirko Goldmann
- Instituto de Física Interdisciplinar y Sistemas Complejos (IFISC, UIB-CSIC), Campus Universitat de les Illes Balears, E-07122 Palma de Mallorca, Spain
| | - Ingo Fischer
- Instituto de Física Interdisciplinar y Sistemas Complejos (IFISC, UIB-CSIC), Campus Universitat de les Illes Balears, E-07122 Palma de Mallorca, Spain
| | - Claudio R Mirasso
- Instituto de Física Interdisciplinar y Sistemas Complejos (IFISC, UIB-CSIC), Campus Universitat de les Illes Balears, E-07122 Palma de Mallorca, Spain
| | - Miguel C Soriano
- Instituto de Física Interdisciplinar y Sistemas Complejos (IFISC, UIB-CSIC), Campus Universitat de les Illes Balears, E-07122 Palma de Mallorca, Spain
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7
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Fischer I, Hemberger P. Photoelectron Photoion Coincidence Spectroscopy of Biradicals. Chemphyschem 2023; 24:e202300334. [PMID: 37325876 DOI: 10.1002/cphc.202300334] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2023] [Revised: 06/15/2023] [Accepted: 06/15/2023] [Indexed: 06/17/2023]
Abstract
The electronic structure of biradicals is characterized by the presence of two unpaired electrons in degenerate or near-degenerate molecular orbitals. In particular, some of the most relevant species are highly reactive, difficult to generate cleanly and can only be studied in the gas phase or in matrices. Unveiling their electronic structure is, however, of paramount interest to understand their chemistry. Photoelectron photoion coincidence (PEPICO) spectroscopy is an excellent approach to explore the electronic states of biradicals, because it enables a direct correlation between the detected ions and electrons. This permits to extract unique vibrationally resolved photoion mass-selected threshold photoelectron spectra (ms-TPES) to obtain insight in the electronic structure of both the neutral and the cation. In this review we highlight most recent advances on the spectroscopy of biradicals and biradicaloids, utilizing PEPICO spectroscopy and vacuum ultraviolet (VUV) synchrotron radiation.
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Affiliation(s)
- Ingo Fischer
- Julius-Maximilians-Universität Würzburg, Institut für Physikalische und Theoretische Chemie, Am Hubland, D-97074, Würzburg, Germany
| | - Patrick Hemberger
- Laboratory for Synchrotron Radiation and Femtochemistry, Paul Scherrer Institut (PSI), CH-5232, Villigen, Switzerland
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8
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Estėbanez I, Argyris A, Fischer I. Experimental demonstration of bandwidth enhancement in photonic time delay reservoir computing. Opt Lett 2023; 48:2449-2452. [PMID: 37126295 DOI: 10.1364/ol.485545] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Time delay reservoir computing (TDRC) using semiconductor lasers (SLs) has proven to be a promising photonic analog approach for information processing. One appealing property is that SLs subject to delayed optical feedback and external optical injection, allow for tuning the response bandwidth by changing the level of optical injection. Here we use strong optical injection, thereby expanding the SL's modulation response up to tens of gigahertz. Performing a nonlinear time series prediction task, we demonstrate experimentally that for appropriate operating conditions, our TDRC system can operate with sampling times as small as 11.72 ps, without sacrificing computational performance.
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9
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Karaev E, Gerlach M, Faschingbauer L, Ramler J, Krummenacher I, Lichtenberg C, Hemberger P, Fischer I. Bonding in Low-Coordinated Organoarsenic and Organoantimony Compounds: A Threshold Photoelectron Spectroscopic Investigation. Chemistry 2023:e202300637. [PMID: 36994844 DOI: 10.1002/chem.202300637] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2023] [Revised: 03/28/2023] [Accepted: 03/30/2023] [Indexed: 03/31/2023]
Abstract
Methyl and methylene compounds of arsenic and antimony are studied by photoelectron photoion coincidence spectroscopy to investigate their relative stability. While for As both HAs=CH2, As-CH3 and the methylene compound As=CH2 are identified in the spectrum, the only Sb compound observed is Sb-CH3. Thus, there is a step in the main group 15 between As and Sb, regarding the relative stability of the methyl compounds. Ionization energies, vibrational frequencies and spin-orbit splittings are determined for the methyl compound from photoion mass-selected photoelectron spectra. Although the spectroscopic results for organoantimony resemble those for the previously investigated bismuth compounds, EPR spectroscopic experiments indicate for Sb(CH3)3 a far lower tendency for methyl transfer compared to Bi(CH3)3. The present study concludes investigations on low-valent organopnictogen compounds.
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Affiliation(s)
- Emil Karaev
- Julius-Maximilians-Universität Würzburg: Julius-Maximilians-Universitat Wurzburg, Institute of Physical and Theoretical Chemistry, GERMANY
| | - Marius Gerlach
- Julius-Maximilians-Universität Würzburg: Julius-Maximilians-Universitat Wurzburg, Institute of Physical and Theoretical Chemistry, GERMANY
| | - Lukas Faschingbauer
- Julius-Maximilians-Universität Würzburg: Julius-Maximilians-Universitat Wurzburg, Institute of Physical and Theoretical Chemistry, GERMANY
| | - Jacqueline Ramler
- Philipps-Universität Marburg: Philipps-Universitat Marburg, Department of Chemistry, GERMANY
| | - Ivo Krummenacher
- Julius-Maximilians-Universität Würzburg: Julius-Maximilians-Universitat Wurzburg, Institute of Inorganic Chemistry, GERMANY
| | - Crispin Lichtenberg
- Philipps-Universitat Marburg Fachbereich Chemie, Chemie, Hans-Meerwein-Straße 4, 35032, Marburg, GERMANY
| | - Patrick Hemberger
- Paul Scherrer Institute: Paul Scherrer Institut PSI, Paul-Scherrer Institute, SWITZERLAND
| | - Ingo Fischer
- Julius-Maximilians-Universität Würzburg: Julius-Maximilians-Universitat Wurzburg, Institute of Physical and Theoretical Chemistry, GERMANY
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10
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Issler K, Sturm F, Petersen J, Flock M, Mitrić R, Fischer I, Barreau L, Poisson L. Time-resolved photoelectron spectroscopy of 4-(dimethylamino)benzethyne - an experimental and computational study. Phys Chem Chem Phys 2023; 25:9837-9845. [PMID: 36976260 DOI: 10.1039/d3cp00309d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/29/2023]
Abstract
We investigated the excited-state dynamics of 4-(dimethylamino)benzethyne (4-DMABE) in a combined theoretical and experimental study using surface-hopping simulations and time-resolved ionisation experiments. The simulations predict a decay of the initially excited S2 state into the S1 state in only a few femtoseconds, inducing a subsequent partial twist of the dimethylamino group within ∼100 fs. This leads to drastically reduced Franck-Condon factors for the ionisation transition to the cationic ground state, thus inhibiting the effective ionisation of the molecule, which leads to a vanishing photoelectron signal on a similar timescale as observed in our time-resolved photoelectron spectra. From the phototoelectron spectra, an adiabatic ionisation energy of 7.17 ± 0.02 eV was determined. The experimental decays match the theoretical predictions very well and the combination of both reveals the electronic characteristics of the molecule, namely the role of intramolecular charge transfer (ICT) states in the deactivation pathway of electronically excited 4-DMABE.
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Affiliation(s)
- Kevin Issler
- Institute of Physical and Theoretical Chemistry, University of Würzburg, Am Hubland, D-97074 Würzburg, Germany.
| | - Floriane Sturm
- Institute of Physical and Theoretical Chemistry, University of Würzburg, Am Hubland, D-97074 Würzburg, Germany.
| | - Jens Petersen
- Institute of Physical and Theoretical Chemistry, University of Würzburg, Am Hubland, D-97074 Würzburg, Germany.
| | - Marco Flock
- Institute of Physical and Theoretical Chemistry, University of Würzburg, Am Hubland, D-97074 Würzburg, Germany.
| | - Roland Mitrić
- Institute of Physical and Theoretical Chemistry, University of Würzburg, Am Hubland, D-97074 Würzburg, Germany.
| | - Ingo Fischer
- Institute of Physical and Theoretical Chemistry, University of Würzburg, Am Hubland, D-97074 Würzburg, Germany.
| | - Lou Barreau
- Institut des Sciences Moléculaires dOrsay (ISMO) UMR 8214, Rue André Rivière, Bâtiment 520, Université Paris-Saclay, F-91405 Orsay Cedex, France.
| | - Lionel Poisson
- Institut des Sciences Moléculaires dOrsay (ISMO) UMR 8214, Rue André Rivière, Bâtiment 520, Université Paris-Saclay, F-91405 Orsay Cedex, France.
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11
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Preitschopf T, Sturm F, Stroganova I, Lemmens AK, Rijs AM, Fischer I. IR/UV Double Resonance Study of the 2-Phenylallyl Radical and its Pyrolysis Products. Chemistry 2023; 29:e202202943. [PMID: 36479856 DOI: 10.1002/chem.202202943] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2022] [Revised: 12/07/2022] [Accepted: 12/07/2022] [Indexed: 12/13/2022]
Abstract
Isolated 2-phenylallyl radicals (2-PA), generated by pyrolysis from a nitrite precursor, have been investigated by IR/UV ion dip spectroscopy using free electron laser radiation. 2-PA is a resonance-stabilized radical that is considered to be involved in the formation of polycyclic aromatic hydrocarbons (PAH) in combustion, but also in interstellar space. The radical is identified based on its gas-phase IR spectrum. Furthermore, a number of bimolecular reaction products are identified, showing that the self-reaction as well as reactions with unimolecular decomposition products of 2-PA form several PAH efficiently. Possible mechanisms are discussed and the chemistry of 2-PA is compared with the one of the related 2-methylallyl and phenylpropargyl radicals.
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Affiliation(s)
- Tobias Preitschopf
- Institute of Physical and Theoretical Chemistry, University of Würzburg, Am Hubland, 97074, Würzburg, Germany
| | - Floriane Sturm
- Institute of Physical and Theoretical Chemistry, University of Würzburg, Am Hubland, 97074, Würzburg, Germany
| | - Iuliia Stroganova
- Division of BioAnalytical Chemistry, AIMMS Amsterdam Institute of Molecular and Life Sciences, Faculty of Science, Vrije Universiteit Amsterdam, De Boelelaan 1081, 1081 HV, Amsterdam, The Netherlands
| | - Alexander K Lemmens
- Institute for Molecules and Materials, FELIX Laboratory, Radboud University, Toernooiveld 7, 6525 ED, Nijmegen, The Netherlands
| | - Anouk M Rijs
- Division of BioAnalytical Chemistry, AIMMS Amsterdam Institute of Molecular and Life Sciences, Faculty of Science, Vrije Universiteit Amsterdam, De Boelelaan 1081, 1081 HV, Amsterdam, The Netherlands
| | - Ingo Fischer
- Institute of Physical and Theoretical Chemistry, University of Würzburg, Am Hubland, 97074, Würzburg, Germany
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12
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Pflüger M, Brunner D, Heuser T, Lott JA, Reitzenstein S, Fischer I. Injection locking and coupling the emitters of large VCSEL arrays via diffraction in an external cavity. Opt Express 2023; 31:8704-8713. [PMID: 36859980 DOI: 10.1364/oe.473449] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/21/2022] [Accepted: 12/08/2022] [Indexed: 06/18/2023]
Abstract
Networks of semiconductor lasers are the foundation of numerous applications and fundamental investigations in nonlinear dynamics, material processing, lighting, and information processing. However, making the usually narrowband semiconductor lasers within the network interact requires both high spectral homogeneity and a fitting coupling concept. Here, we report how we use diffractive optics in an external cavity to experimentally couple vertical-cavity surface-emitting lasers (VCSELs) in a 5×5 array. Out of the 25 lasers, we succeed to spectrally align 22, all of which we lock simultaneously to an external drive laser. Furthermore, we show the considerable coupling interactions between the lasers of the array. This way, we present the largest network of optically coupled semiconductor lasers reported so far and the first detailed characterization of such a diffractively coupled system. Due to the high homogeneity of the lasers, the strong interaction between them, and the scalability of the coupling approach, our VCSEL network is a promising platform for experimental investigations of complex systems, and it has direct applications as a photonic neural network.
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13
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Gerlach M, Mant BP, Preitschopf T, Karaev E, Mayer D, Quitian-Lara H, Hemberger P, Bozek JD, Worth G, Fischer I. Photoelectron spectroscopy and dissociative photoionization of fulminic acid, HCNO. J Chem Phys 2023; 158:134303. [PMID: 37031131 DOI: 10.1063/5.0142194] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/15/2023] Open
Abstract
We report a joint experimental and computational study of the photoelectron spectroscopy and the dissociative photoionization of fulminic acid, HCNO. The molecule is of interest to astrochemistry and astrobiology as a potential precursor of prebiotic molecules. Synchrotron radiation was used as the photon source. Dispersive photoelectron spectra were recorded from 10~eV to 22~eV, covering four band systems in the HCNO cation and an ionization energy of 10.83~eV was determined. Transitions into the Renner-Teller distorted $X^+{}^2\Pi$ state of the cation were simulated using wavepacket dynamics based on a vibronic coupling Hamiltonian. Very good agreement between experiment and theory is obtained. While the first excited state of the cation shows only a broad and unstructured spectrum, the next two higher states exhibit a well-resolved vibrational progression. Transitions into the excited electronic states of \cation{HCNO}{+} were not simulated, due to the large number of electronic states that contribute to these transitions. Nevertheless, a qualitative assignment is given, based on the character of the orbitals involved in the transitions. The dissociative photoionization was investigated by photoelectron-photoion coincidence spectroscopy. The breakdown diagram shows evidence for isomerization from \cation{HCNO}{+} to \cation{HNCO}{+} on the cationic potential energy surface. Zero Kelvin appearance energies for the daughter ions \cation{HCO}{+} and \cation{NCO}{+} have been derived.
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Affiliation(s)
- Marius Gerlach
- Institut für physkalische und theoretische Chemie, Universität Würzburg, Germany
| | | | | | | | | | | | | | | | - Graham Worth
- Chemistry, University College London Department of Chemistry, United Kingdom
| | - Ingo Fischer
- Institute of Physical and Theoretical Chemistry, Universität Würzburg, Germany
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14
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Schleier D, Gerlach M, Schaffner D, Mukhopadhyay DP, Hemberger P, Fischer I. Threshold photoelectron spectroscopy of trimethylborane and its pyrolysis products. Phys Chem Chem Phys 2023; 25:4511-4518. [PMID: 36445209 DOI: 10.1039/d2cp04513c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Trimethylborane (TMB) and its chemistry upon pyrolysis have been investigated by threshold photoelectron spectroscopy. TMB shows an unstructured spectrum and its adiabatic ionization energy (IEad) has been determined to be 9.93 ± 0.1 eV. Dissociative photoionization induces a methyl radical loss in TMB and the barrier to dissociation in the cation is measured to be 0.65 ± 0.1 eV. Upon pyrolysis methane loss dominates, leading to C2H5B, which can exist in five different isomeric structures. Quantum chemical calculations were used to investigate possible methane loss mechanisms as well as the isomerization pathways on the C2H5B potential energy surface. Through isomer-selective photoion mass-selected threshold photoelectron spectroscopy (ms-TPES) the two isomers CH3BCH2 and CH3CHBH were identified by their ms-TPE spectra and IEad values of 8.55 ± 0.02 eV and 8.73 ± 0.02 eV were determined, respectively. A second channel leading to the loss of ethene from TMB forms CH2BH, which exhibits an IEad value of 9.37 ± 0.03 eV. The reaction mechanism in the literature needs to be expanded by an additional methane loss from the intermediately formed ethyl methyl borane.
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Affiliation(s)
- Domenik Schleier
- Institute for Physical and Theoretical Chemistry, University of Würzburg, 97074, Würzburg, Germany.
| | - Marius Gerlach
- Institute for Physical and Theoretical Chemistry, University of Würzburg, 97074, Würzburg, Germany.
| | - Dorothee Schaffner
- Institute for Physical and Theoretical Chemistry, University of Würzburg, 97074, Würzburg, Germany.
| | - Deb Pratim Mukhopadhyay
- Institute for Physical and Theoretical Chemistry, University of Würzburg, 97074, Würzburg, Germany.
| | - Patrick Hemberger
- Laboratory for Synchrotron Radiation and Femtochemistry, Paul Scherrer Institute (PSI), 5232, Villigen, Switzerland.
| | - Ingo Fischer
- Institute for Physical and Theoretical Chemistry, University of Würzburg, 97074, Würzburg, Germany.
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15
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Abstract
Due to their unusual electronic structure, the biradical m-benzyne, C6H4, and its cation are of considerable interest in chemistry. Here, the photoion mass-selected threshold photoelectron spectrum of the m-benzyne biradical is presented. An adiabatic ionization energy of 8.65 ± 0.015 eV is derived, while a vibrational progression of 0.10 eV is assigned to the ν9+ ring breathing mode, in excellent agreement with computations. The experimental spectrum was reproduced well by Franck-Condon spectral modeling of the 2A1 ← X 1A1 transition, in which the cation retains a monocyclic C6 framework. The energetically close-lying bicyclic 2A2 cation state exhibits low Franck-Condon factors, due to the large change in geometry, and thus cannot be observed.
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Affiliation(s)
- M Gerlach
- Institute of Physical and Theoretical Chemistry, University of Würzburg, Am Hubland, D-97074 Würzburg, Germany
| | - E Karaev
- Institute of Physical and Theoretical Chemistry, University of Würzburg, Am Hubland, D-97074 Würzburg, Germany
| | - D Schaffner
- Institute of Physical and Theoretical Chemistry, University of Würzburg, Am Hubland, D-97074 Würzburg, Germany
| | - P Hemberger
- Laboratory for Synchrotron Radiation and Femtochemistry, Paul Scherrer Institut (PSI), CH-5232 Villigen-PSI, Switzerland
| | - I Fischer
- Institute of Physical and Theoretical Chemistry, University of Würzburg, Am Hubland, D-97074 Würzburg, Germany
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16
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Abstract
Reservoir computing is a machine learning approach that can generate a surrogate model of a dynamical system. It can learn the underlying dynamical system using fewer trainable parameters and, hence, smaller training data sets than competing approaches. Recently, a simpler formulation, known as next-generation reservoir computing, removed many algorithm metaparameters and identified a well-performing traditional reservoir computer, thus simplifying training even further. Here, we study a particularly challenging problem of learning a dynamical system that has both disparate time scales and multiple co-existing dynamical states (attractors). We compare the next-generation and traditional reservoir computer using metrics quantifying the geometry of the ground-truth and forecasted attractors. For the studied four-dimensional system, the next-generation reservoir computing approach uses ∼ 1.7 × less training data, requires 10 × shorter "warmup" time, has fewer metaparameters, and has an ∼ 100 × higher accuracy in predicting the co-existing attractor characteristics in comparison to a traditional reservoir computer. Furthermore, we demonstrate that it predicts the basin of attraction with high accuracy. This work lends further support to the superior learning ability of this new machine learning algorithm for dynamical systems.
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Affiliation(s)
- Daniel J Gauthier
- Department of Physics, The Ohio State University, 191 West Woodruff Ave., Columbus, Ohio 43210, USA
| | - Ingo Fischer
- Instituto de Física Interdisciplinar y Sistemas Complejos, IFISC (CSIC-UIB), Campus Universitat Illes Balears, E-07122 Palma de Mallorca, Spain
| | - André Röhm
- Department of Information Physics and Computing, Graduate School of Information Science and Technology, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan
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17
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Goldmann M, Mirasso CR, Fischer I, Soriano MC. Learn one size to infer all: Exploiting translational symmetries in delay-dynamical and spatiotemporal systems using scalable neural networks. Phys Rev E 2022; 106:044211. [PMID: 36397530 DOI: 10.1103/physreve.106.044211] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2021] [Accepted: 09/27/2022] [Indexed: 06/16/2023]
Abstract
We design scalable neural networks adapted to translational symmetries in dynamical systems, capable of inferring untrained high-dimensional dynamics for different system sizes. We train these networks to predict the dynamics of delay-dynamical and spatiotemporal systems for a single size. Then, we drive the networks by their own predictions. We demonstrate that by scaling the size of the trained network, we can predict the complex dynamics for larger or smaller system sizes. Thus, the network learns from a single example and by exploiting symmetry properties infers entire bifurcation diagrams.
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Affiliation(s)
- Mirko Goldmann
- Instituto de Física Interdisciplinar y Sistemas Complejos (IFISC, UIB-CSIC), Campus Universitat de les Illes Balears E-07122, Palma de Mallorca, Spain
| | - Claudio R Mirasso
- Instituto de Física Interdisciplinar y Sistemas Complejos (IFISC, UIB-CSIC), Campus Universitat de les Illes Balears E-07122, Palma de Mallorca, Spain
| | - Ingo Fischer
- Instituto de Física Interdisciplinar y Sistemas Complejos (IFISC, UIB-CSIC), Campus Universitat de les Illes Balears E-07122, Palma de Mallorca, Spain
| | - Miguel C Soriano
- Instituto de Física Interdisciplinar y Sistemas Complejos (IFISC, UIB-CSIC), Campus Universitat de les Illes Balears E-07122, Palma de Mallorca, Spain
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18
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Miao X, Preitschopf T, Sturm F, Fischer I, Lemmens AK, Limbacher M, Mitric R. Stacking Is Favored over Hydrogen Bonding in Azaphenanthrene Dimers. J Phys Chem Lett 2022; 13:8939-8944. [PMID: 36135713 DOI: 10.1021/acs.jpclett.2c02280] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
N-Doped polycyclic aromatic hydrocarbons have recently emerged as potential organic electronic materials. The function of such materials is determined not only by the intrinsic electronic properties of individual molecules but also by their supramolecular interactions in the solid state. Therefore, a proper characterization of the interactions between the individual units is of interest to materials science since they ultimately govern properties such as excitons and charge transfer. Here, we report a joint experimental and computational study of two azaphenanthrene dimers to determine the structure and the nature of supramolecular interactions in the aggregates. IR/UV double-resonance experiments were carried out using far- and mid-infrared free-electron laser radiation. The experimental spectra are compared with quantum chemical calculations for the lowest-energy π-stacked and hydrogen-bonded structures. The data reveal a preference of the π-stacked structure for the benzo[f]quinoline and the phenanthridine dimer.
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Affiliation(s)
- Xincheng Miao
- Institute of Physical and Theoretical Chemistry, University of Würzburg, Am Hubland, D-97074 Würzburg, Germany
| | - Tobias Preitschopf
- Institute of Physical and Theoretical Chemistry, University of Würzburg, Am Hubland, D-97074 Würzburg, Germany
| | - Floriane Sturm
- Institute of Physical and Theoretical Chemistry, University of Würzburg, Am Hubland, D-97074 Würzburg, Germany
| | - Ingo Fischer
- Institute of Physical and Theoretical Chemistry, University of Würzburg, Am Hubland, D-97074 Würzburg, Germany
| | - Alexander K Lemmens
- Institute for Molecules and Materials, FELIX Laboratory, Radboud University, Toernooiveld 7c, 6525 ED Nijmegen, The Netherlands
| | - Moritz Limbacher
- Institute of Physical and Theoretical Chemistry, University of Würzburg, Am Hubland, D-97074 Würzburg, Germany
| | - Roland Mitric
- Institute of Physical and Theoretical Chemistry, University of Würzburg, Am Hubland, D-97074 Würzburg, Germany
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19
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Ramler J, Stoy A, Preitschopf T, Kettner J, Fischer I, Roling B, Fantuzzi F, Lichtenberg C. Dihalo bismuth cations: unusual coordination properties and inverse solvent effects in Lewis acidity. Chem Commun (Camb) 2022; 58:9826-9829. [PMID: 35975673 DOI: 10.1039/d2cc04017d] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A series of well-defined cationic hepta-coordinate bismuth halides [BiX2(py)5][B(3,5-(CF3)2-C6H3)4] (X = Cl, Br, I), stabilized only by substitutionally labile solvent molecules, were synthesized and fully characterized. Their apparent D5h symmetry with a lone pair at the central atom is unprecedented for main group compounds. The potential of BiX3 to show unexpectedly high Lewis acidities in moderately polar solvents is likely due to the formation of [BiX2(solv)5]+ and related ionic species.
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Affiliation(s)
- Jacqueline Ramler
- Institute of Inorganic Chemistry, Julius-Maximilians-University Würzburg, Am Hubland, 97074, Würzburg, Germany
| | - Andreas Stoy
- Department of Chemistry, Philipps-University Marburg, Hans-Meerwein-Str. 4, 35032, Marburg, Germany.
| | - Tobias Preitschopf
- Institute of Physical and Theoretical Chemistry, Julius-Maximilians-University Würzburg, Am Hubland, 97074, Würzburg, Germany
| | - Janosch Kettner
- Department of Chemistry, Philipps-University Marburg, Hans-Meerwein-Str. 4, 35032, Marburg, Germany.
| | - Ingo Fischer
- Institute of Physical and Theoretical Chemistry, Julius-Maximilians-University Würzburg, Am Hubland, 97074, Würzburg, Germany
| | - Bernhard Roling
- Department of Chemistry, Philipps-University Marburg, Hans-Meerwein-Str. 4, 35032, Marburg, Germany.
| | - Felipe Fantuzzi
- School of Physical Sciences, Ingram Building, University of Kent, Park Wood Rd, Canterbury, CT2 7NH, UK.
| | - Crispin Lichtenberg
- Institute of Inorganic Chemistry, Julius-Maximilians-University Würzburg, Am Hubland, 97074, Würzburg, Germany.,Department of Chemistry, Philipps-University Marburg, Hans-Meerwein-Str. 4, 35032, Marburg, Germany.
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20
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Podewski AF, Glimm AM, Fischer I, Bruyn GAW, Hanova P, Hammer HB, Aga AB, Haavardsholm EA, Ramiro S, Burmester GR, Backhaus M, Ohrndorf S. The MCP2 and the wrist plus two extensor compartments are the most affected and responsive joints/tendons out of the US7 score in patients with rheumatoid arthritis-an observational study. Arthritis Res Ther 2022; 24:183. [PMID: 35932087 PMCID: PMC9354335 DOI: 10.1186/s13075-022-02874-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2022] [Accepted: 07/18/2022] [Indexed: 11/25/2022] Open
Abstract
Background There is no international consensus on an optimal ultrasound score for monitoring of rheumatoid arthritis (RA) on patient-level yet. Our aim was to reassess the US7 score for the identification of the most frequently pathologic and responsive joint/tendon regions, to optimize it and contribute to an international consensus. Furthermore, we aimed to evaluate the impact of disease duration on the performance of the score. Methods RA patients were assessed at baseline and after 3 and 6 months of starting/changing DMARD therapy by the US7 score in greyscale (GS) and power Doppler (PD). The frequency of pathologic joint/tendon regions and their responsiveness to therapy were analyzed by Friedman test and Cochrane-Q test respectively, including the comparison of palmar vs. dorsal regions (chi-square test). The responsiveness of different reduced scores and the amount of information retained from the original US7 score were assessed by standardized response means (SRM)/linear regression. Analyses were also performed separately for early and established RA. Results A total of 435 patients (N = 138 early RA) were included (56.5 (SD 13.1) years old, 8.2 (9.1) years disease duration, 80% female). The dorsal wrist, palmar MCP2, extensor digitorum communis (EDC) and carpi ulnaris (ECU) tendons were most frequently affected by GS/PD synovitis/tenosynovitis (wrist: 45%/43%; MCP2: 35%/28%; EDC: 30%/11% and ECU: 25%/11%) and significantly changed within 6 months of therapy (all p ≤0.003 by GS/PD). The dorsal vs. palmar side of the wrist by GS/PD (p < 0.001) and the palmar side of the finger joints by PD (p < 0.001) were more frequently pathologic. The reduced US7 score (GS/PD: palmar MCP2, dorsal wrist, EDC and ECU, only PD: dorsal MCP2) showed therapy response (SRM 0.433) after 6 months and retained 76% of the full US7 score’s information. No major differences between the groups of early and established RA could be detected. Conclusions The wrist, MCP2, EDC, and ECU tendons were most frequently pathologic and responsive to therapy in both early and established RA and should therefore be included in a comprehensive score for monitoring RA patients on patient-level. Supplementary Information The online version contains supplementary material available at 10.1186/s13075-022-02874-y.
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Affiliation(s)
- A F Podewski
- Department of Rheumatology and Clinical Immunology, Charité - Universitätsmedizin Berlin, Berlin, Germany. .,Department of Internal Medicine - Rheumatology and Clinical Immunology, Park-Klinik Weißensee, Berlin, Germany.
| | - A M Glimm
- Department of Endocrinology, Nephrology, Rheumatology, Division Rheumatology, Universitätsklinikum Leipzig, Leipzig, Germany
| | - I Fischer
- Biostatistics Tubingen, Tubingen, Germany
| | - G A W Bruyn
- Department of Rheumatology, MC Groep Hospitals, Lelystad, Netherlands
| | - P Hanova
- Department of Rheumatology, First Faculty of Medicine, Charles University of Prague, Prague, Czech Republic
| | - H B Hammer
- Center for treatment of Rheumatic and Musculoskeletal Diseases (REMEDY), Diakonhjemmet Hospital, Oslo, Norway.,Faculty of Medicine, University of Oslo, Oslo, Norway
| | - A B Aga
- Center for treatment of Rheumatic and Musculoskeletal Diseases (REMEDY), Diakonhjemmet Hospital, Oslo, Norway
| | - E A Haavardsholm
- Center for treatment of Rheumatic and Musculoskeletal Diseases (REMEDY), Diakonhjemmet Hospital, Oslo, Norway.,Faculty of Medicine, University of Oslo, Oslo, Norway
| | - S Ramiro
- Department of Rheumatology, Leiden University Medical Center, Leiden, The Netherlands.,Zuyderland Medical Center, Heerlen, The Netherlands
| | - G R Burmester
- Department of Rheumatology and Clinical Immunology, Charité - Universitätsmedizin Berlin, Berlin, Germany
| | - M Backhaus
- Department of Rheumatology and Clinical Immunology, Charité - Universitätsmedizin Berlin, Berlin, Germany.,Department of Internal Medicine - Rheumatology and Clinical Immunology, Park-Klinik Weißensee, Berlin, Germany
| | - S Ohrndorf
- Department of Rheumatology and Clinical Immunology, Charité - Universitätsmedizin Berlin, Berlin, Germany
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21
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Schleier D, Gerlach M, Pratim Mukhopadhyay D, Karaev E, Schaffner D, Hemberger P, Fischer I. Cover Feature: Ammonia Borane, NH
3
BH
3
: A Threshold Photoelectron–Photoion Coincidence Study of a Potential Hydrogen‐Storage Material (Chem. Eur. J. 42/2022). Chemistry 2022. [DOI: 10.1002/chem.202201981] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Domenik Schleier
- Institute of Physical and Theoretical Chemistry University of Würzburg Am Hubland 97074 Würzburg Germany
- Present Address: Laboratory for Astrophysics Leiden Observatory Leiden University 2300 RA Leiden (The Netherlands
| | - Marius Gerlach
- Institute of Physical and Theoretical Chemistry University of Würzburg Am Hubland 97074 Würzburg Germany
| | - Deb Pratim Mukhopadhyay
- Institute of Physical and Theoretical Chemistry University of Würzburg Am Hubland 97074 Würzburg Germany
- Present address: Department of Dynamics of Molecules and Clusters J. Heyrovský Institute of Physical Chemistry Dolejškova 2155/3 182 23 Praha 8 Czech Republic
| | - Emil Karaev
- Institute of Physical and Theoretical Chemistry University of Würzburg Am Hubland 97074 Würzburg Germany
| | - Dorothee Schaffner
- Institute of Physical and Theoretical Chemistry University of Würzburg Am Hubland 97074 Würzburg Germany
| | - Patrick Hemberger
- Laboratory for Synchrotron Radiation and Femtochemistry Paul Scherrer Institut (PSI) 5232 Villigen Switzerland
| | - Ingo Fischer
- Institute of Physical and Theoretical Chemistry University of Würzburg Am Hubland 97074 Würzburg Germany
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22
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Schleier D, Gerlach M, Pratim Mukhopadhyay D, Karaev E, Schaffner D, Hemberger P, Fischer I. Ammonia Borane, NH 3 BH 3 : A Threshold Photoelectron-Photoion Coincidence Study of a Potential Hydrogen-Storage Material. Chemistry 2022; 28:e202201378. [PMID: 35622451 PMCID: PMC9401591 DOI: 10.1002/chem.202201378] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2022] [Indexed: 12/17/2022]
Abstract
We have investigated the photoionization of ammonia borane (AB) and determined adiabatic ionization energy to be 9.26±0.03 eV for the X+ 2E←X 1A1 transition. Although the threshold photoelectron spectrum appears at first glance to be similar to the one of the isosteric ethane, the electronic situation differs markedly, due to different orbital energies. In addition, an appearance energy AE0K(NH3BH3, NH3BH2+)= 10.00±0.03 eV has been determined, corresponding to the loss of a hydrogen atom at the BH3‐site. From the data, a 0 K bond dissociation energy for the B−H bond in the cation of 71.5±3 kJ mol−1 was derived, whereas the one in the neutral compound has been estimated to be 419±10 kJ mol−1.
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Affiliation(s)
- Domenik Schleier
- Institute of Physical and Theoretical Chemistry, University of Würzburg, Am Hubland, 97074, Würzburg, Germany.,Present Address: Laboratory for Astrophysics, Leiden Observatory, Leiden University, 2300 RA, Leiden (The, Netherlands
| | - Marius Gerlach
- Institute of Physical and Theoretical Chemistry, University of Würzburg, Am Hubland, 97074, Würzburg, Germany
| | - Deb Pratim Mukhopadhyay
- Institute of Physical and Theoretical Chemistry, University of Würzburg, Am Hubland, 97074, Würzburg, Germany.,Present address: Department of Dynamics of Molecules and Clusters, J. Heyrovský Institute of Physical Chemistry, Dolejškova 2155/3, 182 23, Praha 8, Czech Republic
| | - Emil Karaev
- Institute of Physical and Theoretical Chemistry, University of Würzburg, Am Hubland, 97074, Würzburg, Germany
| | - Dorothee Schaffner
- Institute of Physical and Theoretical Chemistry, University of Würzburg, Am Hubland, 97074, Würzburg, Germany
| | - Patrick Hemberger
- Laboratory for Synchrotron Radiation and Femtochemistry, Paul Scherrer Institut (PSI), 5232, Villigen, Switzerland
| | - Ingo Fischer
- Institute of Physical and Theoretical Chemistry, University of Würzburg, Am Hubland, 97074, Würzburg, Germany
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23
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Lehner U, Zaretsky E, Goeze A, Wermter L, Stuck BA, Birk R, Neff A, Fischer I, Ghanaati S, Sader R, Hey C. [Pre-treatment dysphagia in head-and-neck cancer patients]. HNO 2022; 70:533-539. [PMID: 35122104 PMCID: PMC9242961 DOI: 10.1007/s00106-021-01128-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/11/2021] [Indexed: 12/03/2022]
Abstract
BACKGROUND The swallowing and nutritional status of head-and-neck cancer patients after oncological therapy have been extensively researched. However, the same topics are seldom scrutinized before the onset of oncological therapy, although they can influence treatment success in the long term. OBJECTIVE This study focusses on a systematic assessment of swallowing function and nutritional status in head-and-neck cancer patients prior to oncological therapy. MATERIALS AND METHODS In 102 patients, penetration/aspiration (PA scale), limitations of oral intake (Functional Oral Intake Scale, FOIS), and the need for further intervention (NFI) were endoscopically assessed to objectively quantify swallowing function. The subjective evaluation of swallowing function was carried out with the gEAT-10 (German EAT-10) questionnaire, nutritional status was assessed by body mass index (BMI). Possible impact factors for swallowing function and BMI were analyzed by univariate and multivariate methods. RESULTS PAS, FOIS, and NFI values were abnormal in ≤ 15% of patients. BMI was more often too high than too low. Objectively assessed swallowing functions depended predominantly on tumor stage and showed moderate correlations with gEAT-10. The latter mostly yielded a "fail" result. The nutritional status depended on the patients' biological sex and NFI. CONCLUSION In the pre-treatment setting, neither dysphagia nor malnutrition were found in most patients. Impaired swallowing was associated with higher tumor stages, malnutrition with female sex and NFI. A systematic pre-treatment assessment of swallowing and nutritional status in head-and-neck cancer patients appears necessary for modern oncological therapy and optimal patient outcome.
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Affiliation(s)
- Uta Lehner
- Abteilung für Phoniatrie und Pädaudiologie, HNO, Universitätsklinikum Gießen und Marburg GmbH, Standort Marburg, Philipps-Universität Marburg, Baldingerstr. 1, 35043, Marburg, Deutschland
| | - Eugen Zaretsky
- Abteilung für Phoniatrie und Pädaudiologie, HNO, Universitätsklinikum Gießen und Marburg GmbH, Standort Marburg, Philipps-Universität Marburg, Baldingerstr. 1, 35043, Marburg, Deutschland.
| | - Almut Goeze
- Abteilung für Phoniatrie und Pädaudiologie, HNO, Universitätsklinikum Gießen und Marburg GmbH, Standort Marburg, Philipps-Universität Marburg, Baldingerstr. 1, 35043, Marburg, Deutschland
| | - Laura Wermter
- Abteilung für Phoniatrie und Pädaudiologie, HNO, Universitätsklinikum Gießen und Marburg GmbH, Standort Marburg, Philipps-Universität Marburg, Baldingerstr. 1, 35043, Marburg, Deutschland
| | - Boris A Stuck
- Klinik für Hals‑, Nasen- und Ohrenheilkunde, Universitätsklinikum Gießen und Marburg GmbH, Standort Marburg, Philipps-Universität Marburg, Marburg, Deutschland
| | - Richard Birk
- Klinik für Hals‑, Nasen- und Ohrenheilkunde, Universitätsklinikum Gießen und Marburg GmbH, Standort Marburg, Philipps-Universität Marburg, Marburg, Deutschland
| | - Andreas Neff
- Klinik und Poliklinik für Mund‑, Kiefer- und Gesichtschirurgie, Universitätsklinikum Gießen und Marburg GmbH, Standort Marburg, Philipps-Universität Marburg, Marburg, Deutschland
| | - Ingo Fischer
- Klinik und Poliklinik für Mund‑, Kiefer- und Gesichtschirurgie, Universitätsklinikum Gießen und Marburg GmbH, Standort Marburg, Philipps-Universität Marburg, Marburg, Deutschland
| | - Shahram Ghanaati
- Klinik für Mund‑, Kiefer‑, Plastische Gesichtschirurgie, Universitätsklinikum Frankfurt/Main, Goethe-Universität Frankfurt/Main, Frankfurt/Main, Deutschland
| | - Robert Sader
- Klinik für Mund‑, Kiefer‑, Plastische Gesichtschirurgie, Universitätsklinikum Frankfurt/Main, Goethe-Universität Frankfurt/Main, Frankfurt/Main, Deutschland
| | - Christiane Hey
- Abteilung für Phoniatrie und Pädaudiologie, HNO, Universitätsklinikum Gießen und Marburg GmbH, Standort Marburg, Philipps-Universität Marburg, Baldingerstr. 1, 35043, Marburg, Deutschland
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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] [What about the content of this article? (0)] [Affiliation(s)] [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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Podewski AF, Glimm AM, Fischer I, Bruyn G, Hanova P, Hammer HB, Aga AB, Haavardsholm EA, Ramiro S, Burmester GR, Backhaus M, Ohrndorf S. POS0106 THE MCP2 AND WRIST PLUS 2 TENDONS ARE THE MOST AFFECTED AND RESPONSIVE JOINTS/TENDONS OUT OF THE ‘US7 SCORE’ IN PATIENTS WITH RHEUMATOID ARTHRITIS – AN OBSERVATIONAL STUDY. Ann Rheum Dis 2022. [DOI: 10.1136/annrheumdis-2022-eular.713] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
BackgroundThere is no international consensus on an optimal ultrasound scoring system in patients with rheumatoid arthritis (RA) yet.ObjectivesTo assess the musculoskeletal ultrasound score on seven joints (‘US7 score’) (1) for the identification of the most frequently pathologic and responsive joint regions during 3 and 6 months of therapy in order to optimize the score. Furthermore, to evaluate the impact of disease duration on the performance of the score.MethodsRA patients were recruited from 54 German rheumatology centers when starting or changing DMARD therapy. Patients were assessed by the US7 score in greyscale (GS) and power Doppler (PD) at baseline, after 3 and 6 months. The frequency of pathologic joint/tendon regions and their responsiveness to therapy were assessed including the comparison of palmar vs. dorsal regions.Differences between the palmar and the dorsal sides were analyzed using Chi-square test, the gradings of the US-joint inflammation were compared between baseline, 3 months, and 6 months by Friedman test with Dunn test as post-hoc test.We used standard response mean to determine the responsiveness of possible reduced scores and linear regression to assess the amount of information retained from the original score. Analyses were also performed separately for early and established RA.ResultsA total of 435 patients (n=138 early RA) were included (56.5 (SD 13.1) years old, 8.2 (9.1) years disease duration, 80% female). The dorsal wrist, palmar MCP2, extensor digitorum communis (EDC) and carpi ulnaris (ECU) tendons out of 7 joints were most frequently affected by GS/PD synovitis/tenosynovitis (wrist: 45%/43%; MCP2: 35%/28%; EDC: 30%/11% and ECU: 25%/11%) and significantly changed within 6 months of therapy (all p≤0.003 in GS/PD).The dorsal vs. palmar side of the wrist by GS/PD (p<0.001) and the palmar vs. dorsal side of the finger joints by PD (p<0.001) were more frequently pathologic. The reduced US7 score (GS and PD: dorsal MCP2, dorsal wrist, EDC and ECU, only GS: palmar MCP2) showed therapy response (SRM 0.433) after 6 months and retained 76% of the information of the full US7 score. No major differences between the groups of early and established RA could be detected.ConclusionThe wrist, MCP2, EDC and ECU tendons were most frequently pathologic and responsive to therapy, representing an optimized score for monitoring of RA patients for both early and established RA and should therefore be included in comprehensive scores for monitoring RA patients.References[1]Backhaus M, Ohrndorf S, Kellner H, Strunk J, Backhaus TM, Hartung W, et al. Evaluation of a novel 7-joint ultrasound score in daily rheumatologic practice: a pilot project. Arthritis Rheum. 2009;61(9):1194-201.AcknowledgementsWe thank Gabriela Schmittat for logistical support in the study.Disclosure of InterestsAnnika Franziska Podewski: None declared, Anne-Marie Glimm: None declared, Imma Fischer: None declared, George Bruyn: None declared, Petra Hanova: None declared, Hilde Berner Hammer Speakers bureau: Paid speaker for Lilly, Novartis and AbbVie, Employee of: Advisory board for AbbVie, Anna-Birgitte Aga Speakers bureau: AbbVie, Eli Lilly, Novartis, Pfizer and UCB, Consultant of: AbbVie, Eli Lilly, Novartis, Pfizer and UCB, Espen A Haavardsholm: None declared, Sofia Ramiro Speakers bureau: Eli Lilly, MSD, Novartis, UCB, Consultant of: AbbVie, Eli Lilly, MSD, Novartis, Pfizer, UCB, Sanofi, Grant/research support from: AbbVie, Galapagos, Novartis, Pfizer, UCB, Gerd Rüdiger Burmester: None declared, Marina Backhaus Speakers bureau: Speaker fee from AbbVie, BMS, Galapagos, UCB, Novartis, Sarah Ohrndorf: None declared
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Mukhopadhyay DP, Gerlach M, Hartweg S, Fischer I, Loison JC. Photoelectron spectroscopy of low valent organophosphorus compounds, P-CH 3, H-PCH 2 and PCH 2. Phys Chem Chem Phys 2022; 24:10993-10999. [PMID: 35467677 DOI: 10.1039/d2cp01082h] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We report the mass-selected slow photoelectron spectra of three reactive organophosphorus species, PCH2, and the two isomers, methylenephosphine or phosphaethylene, HPCH2 and methylphosphinidine, P-CH3. All spectra were recorded by double imaging photoelectron-photoion coincidence spectroscopy (i2PEPICO) using synchrotron radiation and all species were generated in a flow reactor by the reaction of trimethyl phosphine with fluorine atoms. Adiabatic ionisation energies of 8.80 ± 0.02 eV (PCH2), 10.07 ± 0.03 eV (H-PCH2) and 8.91 ± 0.04 eV (P-CH3) were determined and the vibronic structure was simulated by calculating Franck-Condon factors from optimised structures based on quantum chemical methods. Observation of biradicalic P-CH3 isomer with its triplet ground state is surprising because it is less stable than H-PCH2.
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Affiliation(s)
- Deb Pratim Mukhopadhyay
- Institute of Physical and Theoretical Chemistry, University of Würzburg, Am Hubland, D-97074 Würzburg, Germany.
| | - Marius Gerlach
- Institute of Physical and Theoretical Chemistry, University of Würzburg, Am Hubland, D-97074 Würzburg, Germany.
| | - Sebastian Hartweg
- Synchrotron SOLEIL, L'Orme des Merisiers, St Aubin, B. P. 48, F-91192 Gif sur Yvette, France
| | - Ingo Fischer
- Institute of Physical and Theoretical Chemistry, University of Würzburg, Am Hubland, D-97074 Würzburg, Germany.
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Abstract
Resonance-stabilized radicals are considered as possible intermediates in the formation of polycyclic aromatic hydrocarbons (PAHs) in interstellar space. Here, we investigate the fulvenallenyl radical, the most stable C7H5 isomer by IR/UV ion dip spectroscopy employing free electron laser radiation in the mid-infrared region between 550 and 1750 cm-1. The radical is generated by pyrolysis from phthalide. Various jet-cooled reaction products are identified by their mass-selective IR spectra in the fingerprint region, based on a comparison with computed spectra. Interestingly, benzyl is present as a second resonance-stabilized radical. It is connected to fulvenallenyl by a sequence of two H atom losses or additions. Among the identified aromatic hydrocarbons are toluene and styrene, as well as polycyclic molecules, such as indene, naphthalene, fluorene and phenanthrene. Mechanisms for the formation of PAH from C7H5 have already been suggested in previous computational work. In particular, the radical/radical reaction of two fulvenallenyl radicals provides an efficient route to phenanthrene in one bimolecular step and might be relevant for PAH formation under astrochemical conditions.
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Affiliation(s)
- Florian Hirsch
- Institute of Physical and Theoretical Chemistry, University of Würzburg, Am Hubland, D-97074 Würzburg, Germany
| | - Ingo Fischer
- Institute of Physical and Theoretical Chemistry, University of Würzburg, Am Hubland, D-97074 Würzburg, Germany
| | - Sjors Bakels
- Radboud University, Institute for Molecules and Materials, FELIX Laboratory, Toernooiveld 7c, 6525 ED Nijmegen, The Netherlands
| | - Anouk M Rijs
- Radboud University, Institute for Molecules and Materials, FELIX Laboratory, Toernooiveld 7c, 6525 ED Nijmegen, The Netherlands
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Preitschopf T, Hirsch F, Lemmens AK, Rijs AM, Fischer I. The gas-phase infrared spectra of the 2-methylallyl radical and its high-temperature reaction products. Phys Chem Chem Phys 2022; 24:7682-7690. [PMID: 35302151 DOI: 10.1039/d2cp00400c] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The resonance-stabilized 2-methylallyl radical, 2-MA, is considered as a possible intermediate in the formation of polycyclic aromatic hydrocarbons (PAHs) in combustion processes. In this work, we report on its contribution to molecular growth in a high-temperature microreactor and provide mass-selective IR/UV ion dip spectra of the radical, as well as the various jet-cooled reaction products, employing free electron laser radiation in the mid-infrared region. Small (aromatic) hydrocarbons such as fulvene, benzene, styrene, or para-xylene, as well as polycyclic molecules, like (methylated) naphthalene, were identified with the aid of ab initio DFT computations. Several reaction products differ by one or more methyl groups, suggesting that molecular growth is dominated by (de)methylation in the reactor.
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Affiliation(s)
- Tobias Preitschopf
- Institute of Physical and Theoretical Chemistry, University of Wuerzburg, Am Hubland, 97074 Würzburg, Germany.
| | - Florian Hirsch
- Institute of Physical and Theoretical Chemistry, University of Wuerzburg, Am Hubland, 97074 Würzburg, Germany.
| | - Alexander K Lemmens
- Radboud University, Institute for Molecules and Materials, FELIX Laboratory, Toernooiveld 7, 6525 ED Nijmegen, The Netherlands.
| | - Anouk M Rijs
- Radboud University, Institute for Molecules and Materials, FELIX Laboratory, Toernooiveld 7, 6525 ED Nijmegen, The Netherlands.
| | - Ingo Fischer
- Institute of Physical and Theoretical Chemistry, University of Wuerzburg, Am Hubland, 97074 Würzburg, Germany.
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Abstract
Photoelectron spectroscopy has long been a powerful method in the toolbox of experimental physical chemistry and molecular physics. Recent improvements in coincidence methods, charged-particle imaging, and electron energy resolution have greatly expanded the variety of environments in which photoelectron spectroscopy can be applied, as well as the range of questions that can now be addressed. In this Perspectives Article, we focus on selected recent studies that highlight these advances and research areas. The topics include reactive intermediates and new thermochemical data, high-resolution comparisons of experiment and theory using methods based on pulsed-field ionisation (PFI), and the application of photoelectron spectroscopy as an analytical tool to monitor chemical reactions in complex environments, like model flames, catalytic or high-temperature reactors.
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Affiliation(s)
- Ingo Fischer
- Institute of Physical and Theoretical Chemistry, University of Würzburg, Am Hubland, D-97074 Würzburg, Germany.
| | - Stephen T Pratt
- Chemical Sciences and Engineering Division, Argonne National Laboratory, Lemont, IL 60439, USA.
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Matthaei CT, Mukhopadhyay DP, Röder A, Poisson L, Fischer I. Photodissociation of the trichloromethyl radical: photofragment imaging and femtosecond photoelectron spectroscopy. Phys Chem Chem Phys 2022; 24:928-940. [PMID: 34913455 DOI: 10.1039/d1cp04084g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Halogen-containing radicals play a key role in catalytic reactions leading to stratospheric ozone destruction, thus their photochemistry is of considerable interest. Here we investigate the photodissociation dynamics of the trichloromethyl radical, CCl3 after excitation in the ultraviolet. While the primary processes directly after light absorption are followed by femtosecond-time resolved photoionisation and photoelectron spectroscopy, the reaction products are monitored by photofragment imaging using nanosecond-lasers. The dominant reaction is loss of a Cl atom, associated with a CCl2 fragment. However, the detection of Cl atoms is of limited value, because in the pyrolysis CCl2 is formed as a side product, which in turn dissociates to CCl + Cl. We therefore additionally monitored the molecular fragments CCl2 and CCl by photoionisation at 118.2 nm and disentangled the contributions from various processes. A comparison of the CCl images with control experiments on CCl2 suggest that the dissociation to CCl + Cl2 contributes to the photochemistry of CCl3.
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Affiliation(s)
- Christian T Matthaei
- Institute of Physical and Theoretical Chemistry, University of Würzburg, Am Hubland, D-97074 Würzburg, Germany.
| | - Deb Pratim Mukhopadhyay
- Institute of Physical and Theoretical Chemistry, University of Würzburg, Am Hubland, D-97074 Würzburg, Germany.
| | - Anja Röder
- Institute of Physical and Theoretical Chemistry, University of Würzburg, Am Hubland, D-97074 Würzburg, Germany. .,LIDYL, CEA, CNRS, Université Paris-Saclay, CEA Saclay, 91191 Gif-sur-Yvette, France.
| | - Lionel Poisson
- LIDYL, CEA, CNRS, Université Paris-Saclay, CEA Saclay, 91191 Gif-sur-Yvette, France. .,Université Paris-Saclay, CNRS, Institut des Sciences Moléculaires d*Orsay, 91405, Orsay, France
| | - Ingo Fischer
- Institute of Physical and Theoretical Chemistry, University of Würzburg, Am Hubland, D-97074 Würzburg, Germany.
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Abstract
We report the mass-selected threshold photoelectron spectrum (ms-TPES) of iminoborane (HBNH), generated by pyrolysis of borazine. The adiabatic ionization energy (IE) of the X+ 2Π ← X 1Σ+ transition was determined to be 11.31 ± 0.02 eV and the wavenumber of the B-N stretching vibration in the cation was measured to be 1550 cm-1. The Renner-Teller splitting in the X+ 2Π state gives rise to two sets of vibrational progressions, separated by 70 meV.
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Affiliation(s)
- Domenik Schleier
- Institute of Physical and Theoretical Chemistry, University of Würzburg, Am Hubland, Würzburg D-97074, Germany.
| | - Dorothee Schaffner
- Institute of Physical and Theoretical Chemistry, University of Würzburg, Am Hubland, Würzburg D-97074, Germany.
| | - Marius Gerlach
- Institute of Physical and Theoretical Chemistry, University of Würzburg, Am Hubland, Würzburg D-97074, Germany.
| | - Patrick Hemberger
- Laboratory for Femtochemistry and Synchrotron Radiation, Paul Scherrer Institut (PSI), Villigen CH-5232, Switzerland.
| | - Ingo Fischer
- Institute of Physical and Theoretical Chemistry, University of Würzburg, Am Hubland, Würzburg D-97074, Germany.
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Gerlach M, Monninger S, Schleier D, Hemberger P, Goettel JT, Braunschweig H, Fischer I. Photoelectron Photoion Coincidence Spectroscopy of NCl 3 and NCl 2. Chemphyschem 2021; 22:2164-2167. [PMID: 34390518 PMCID: PMC8596423 DOI: 10.1002/cphc.202100537] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2021] [Revised: 08/10/2021] [Indexed: 12/02/2022]
Abstract
We investigate NCl3 and the NCl2 radical by photoelectron‐photoion coincidence spectroscopy using synchrotron radiation. The mass selected threshold photoelectron spectrum (ms‐TPES) of NCl3 is broad and unstructured due to the large geometry change. An ionization energy of 9.7±0.1 eV is estimated from the spectrum and supported by computations. NCl2 is generated by photolysis at 213 nm from NCl3 and its ms‐TPES shows an extended vibrational progression with a 90 meV spacing that is assigned to the symmetric N−Cl stretching mode in the cation. An adiabatic ionization energy of 9.94 ± 0.02 eV is determined.
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Affiliation(s)
- Marius Gerlach
- Institute of Physical and Theoretical Chemistry, University of Würzburg, Am Hubland, 97074, Würzburg, Germany
| | - Sophie Monninger
- Institute of Physical and Theoretical Chemistry, University of Würzburg, Am Hubland, 97074, Würzburg, Germany
| | - Domenik Schleier
- Institute of Physical and Theoretical Chemistry, University of Würzburg, Am Hubland, 97074, Würzburg, Germany
| | - Patrick Hemberger
- Laboratory for Synchrotron Radiation and Femtochemistry, Paul Scherrer Institut (PSI), 5232, Villigen, Switzerland
| | - James T Goettel
- Institute of Inorganic Chemistry and Institute for Sustainable Chemistry and Catalysis with Boron, University of Würzburg, Am Hubland, 97074, Würzburg, Germany
| | - Holger Braunschweig
- Institute of Inorganic Chemistry and Institute for Sustainable Chemistry and Catalysis with Boron, University of Würzburg, Am Hubland, 97074, Würzburg, Germany
| | - Ingo Fischer
- Institute of Physical and Theoretical Chemistry, University of Würzburg, Am Hubland, 97074, Würzburg, Germany
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Röhm A, Gauthier DJ, Fischer I. Model-free inference of unseen attractors: Reconstructing phase space features from a single noisy trajectory using reservoir computing. Chaos 2021; 31:103127. [PMID: 34717323 DOI: 10.1063/5.0065813] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/05/2021] [Accepted: 09/25/2021] [Indexed: 06/13/2023]
Abstract
Reservoir computers are powerful tools for chaotic time series prediction. They can be trained to approximate phase space flows and can thus both predict future values to a high accuracy and reconstruct the general properties of a chaotic attractor without requiring a model. In this work, we show that the ability to learn the dynamics of a complex system can be extended to systems with multiple co-existing attractors, here a four-dimensional extension of the well-known Lorenz chaotic system. We demonstrate that a reservoir computer can infer entirely unexplored parts of the phase space; a properly trained reservoir computer can predict the existence of attractors that were never approached during training and, therefore, are labeled as unseen. We provide examples where attractor inference is achieved after training solely on a single noisy trajectory.
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Affiliation(s)
- André Röhm
- Instituto de Física Interdisciplinar y Sistemas Complejos, IFISC (CSIC-UIB), Campus Universitat Illes Balears, E-07122 Palma de Mallorca, Spain
| | - Daniel J Gauthier
- Department of Physics, The Ohio State University, 191 West Woodruff Ave., Columbus, Ohio 43210, USA
| | - Ingo Fischer
- Instituto de Física Interdisciplinar y Sistemas Complejos, IFISC (CSIC-UIB), Campus Universitat Illes Balears, E-07122 Palma de Mallorca, Spain
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Hoche J, Flock M, Miao X, Philipp LN, Wenzel M, Fischer I, Mitric R. Excimer formation dynamics in the isolated tetracene dimer. Chem Sci 2021; 12:11965-11975. [PMID: 34667562 PMCID: PMC8457379 DOI: 10.1039/d1sc03214c] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2021] [Accepted: 08/01/2021] [Indexed: 12/20/2022] Open
Abstract
The understanding of excimer formation and its interplay with the singlet-correlated triplet pair state 1(TT) is of high significance for the development of efficient organic electronics. Here, we study the photoinduced dynamics of the tetracene dimer in the gas phase by time-resolved photoionisation and photoion imaging experiments as well as nonadiabatic dynamics simulations in order to obtain mechanistic insight into the excimer formation dynamics. The experiments are performed using a picosecond laser system for excitation into the S2 state and reveal a biexponential time dependence. The time constants, obtained as a function of excess energy, lie in the range between ≈10 ps and 100 ps and are assigned to the relaxation of the excimer on the S1 surface and to its deactivation to the ground state. Simulations of the quantum-classical photodynamics are carried out in the frame of the semi-empirical CISD and TD-lc-DFTB methods. Both theoretical approaches reveal a dominating relaxation pathway that is characterised by the formation of a perfectly stacked excimer. TD-lc-DFTB simulations have also uncovered a second relaxation channel into a less stable dimer conformation in the S1 state. Both methods have consistently shown that the electronic and geometric relaxation to the excimer state is completed in less than 10 ps. The inclusion of doubly excited states in the CISD dynamics and their diabatisation further allowed to observe a transient population of the 1(TT) state, which, however, gets depopulated on a timescale of 8 ps, leading finally to the trapping in the excimer minimum. The understanding of excimer formation and its interplay with the singlet-correlated triplet pair state 1(TT) is of high significance for the development of efficient organic electronics.![]()
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Affiliation(s)
- Joscha Hoche
- Institut für Physikalische und Theoretische Chemie, Universität Würzburg Am Hubland 97074 Würzburg Germany
| | - Marco Flock
- Institut für Physikalische und Theoretische Chemie, Universität Würzburg Am Hubland 97074 Würzburg Germany
| | - Xincheng Miao
- Institut für Physikalische und Theoretische Chemie, Universität Würzburg Am Hubland 97074 Würzburg Germany
| | - Luca Nils Philipp
- Institut für Physikalische und Theoretische Chemie, Universität Würzburg Am Hubland 97074 Würzburg Germany
| | - Michael Wenzel
- Institut für Physikalische und Theoretische Chemie, Universität Würzburg Am Hubland 97074 Würzburg Germany
| | - Ingo Fischer
- Institut für Physikalische und Theoretische Chemie, Universität Würzburg Am Hubland 97074 Würzburg Germany
| | - Roland Mitric
- Institut für Physikalische und Theoretische Chemie, Universität Würzburg Am Hubland 97074 Würzburg Germany
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Stelzer F, Röhm A, Vicente R, Fischer I, Yanchuk S. Deep neural networks using a single neuron: folded-in-time architecture using feedback-modulated delay loops. Nat Commun 2021; 12:5164. [PMID: 34453053 PMCID: PMC8397757 DOI: 10.1038/s41467-021-25427-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2021] [Accepted: 08/10/2021] [Indexed: 11/21/2022] Open
Abstract
Deep neural networks are among the most widely applied machine learning tools showing outstanding performance in a broad range of tasks. We present a method for folding a deep neural network of arbitrary size into a single neuron with multiple time-delayed feedback loops. This single-neuron deep neural network comprises only a single nonlinearity and appropriately adjusted modulations of the feedback signals. The network states emerge in time as a temporal unfolding of the neuron's dynamics. By adjusting the feedback-modulation within the loops, we adapt the network's connection weights. These connection weights are determined via a back-propagation algorithm, where both the delay-induced and local network connections must be taken into account. Our approach can fully represent standard Deep Neural Networks (DNN), encompasses sparse DNNs, and extends the DNN concept toward dynamical systems implementations. The new method, which we call Folded-in-time DNN (Fit-DNN), exhibits promising performance in a set of benchmark tasks.
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Affiliation(s)
- Florian Stelzer
- Institute of Mathematics, Technische Universität Berlin, Berlin, Germany
- Department of Mathematics, Humboldt-Universität zu Berlin, Berlin, Germany
- Institute of Computer Science, University of Tartu, Tartu, Estonia
| | - André Röhm
- Instituto de Física Interdisciplinar y Sistemas Complejos, IFISC (UIB-CSIC), Campus Universitat de les Illes Baleares, Palma de Mallorca, Spain
| | - Raul Vicente
- Institute of Computer Science, University of Tartu, Tartu, Estonia
| | - Ingo Fischer
- Instituto de Física Interdisciplinar y Sistemas Complejos, IFISC (UIB-CSIC), Campus Universitat de les Illes Baleares, Palma de Mallorca, Spain
| | - Serhiy Yanchuk
- Institute of Mathematics, Technische Universität Berlin, Berlin, Germany.
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Jaeger A, Prieske K, Mathey S, Fischer I, Vettorazzi E, Kuerti S, Reuter S, Dieckmann J, Schmalfeldt B, Woelber L. Pelvic lymphadenectomy in vulvar cancer and its impact on prognosis and outcome. Arch Gynecol Obstet 2021; 305:233-240. [PMID: 34387725 PMCID: PMC8782795 DOI: 10.1007/s00404-021-06156-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2020] [Accepted: 07/21/2021] [Indexed: 12/20/2022]
Abstract
BACKGROUND The value of pelvic lymphadenectomy (LAE) has been subject of discussions since the 1980s. This is mainly due to the fact that the relation between lymph node involvement of the groin and pelvis is poorly understood and therewith the need for pelvic treatment in general. PATIENTS AND METHODS N = 514 patients with primary vulvar squamous cell cancer (VSCC) FIGO stage ≥ IB were treated at the University Medical Center Hamburg-Eppendorf between 1996 and 2018. In this analysis, patients with pelvic LAE (n = 21) were analyzed with regard to prognosis and the relation of groin and pelvic lymph node involvement. RESULTS The majority had T1b/T2 tumors (n = 15, 78.9%) with a median diameter of 40 mm (11-110 mm). 17/21 patients showed positive inguinal nodes. Pelvic nodal involvement without groin metastases was not observed. 6/17 node-positive patients with positive groin nodes also had pelvic nodal metastases (35.3%; median number of affected pelvic nodes 2.5 (1-8)). These 6 patients were highly node positive with median 4.5 (2-9) affected groin nodes. With regard to the metastatic spread between groins and pelvis, no contralateral spread was observed. Five recurrences were observed after a median follow-up of 33.5 months. No pelvic recurrences were observed in the pelvic nodal positive group. Patients with pelvic metastasis at first diagnosis had a median progression-free survival of only 9.9 months and overall-survival of 31.1 months. CONCLUSION A relevant risk for pelvic nodal involvement only seems to be present in highly node-positive disease, therefore pelvic staging (and radiotherapy) is probably unnecessary in the majority of patients with node-positive VSCC.
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Affiliation(s)
- A Jaeger
- Department of Gynecology and Gynecologic Oncology, University Medical Center Hamburg-Eppendorf, Martinistraße 52, 20246, Hamburg, Germany
| | - K Prieske
- Department of Gynecology and Gynecologic Oncology, University Medical Center Hamburg-Eppendorf, Martinistraße 52, 20246, Hamburg, Germany.,Mildred Scheel Cancer Career Center HaTriCS4, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - S Mathey
- Department of Gynecology and Gynecologic Oncology, University Medical Center Hamburg-Eppendorf, Martinistraße 52, 20246, Hamburg, Germany
| | - I Fischer
- Department of Gynecology and Gynecologic Oncology, University Medical Center Hamburg-Eppendorf, Martinistraße 52, 20246, Hamburg, Germany
| | - E Vettorazzi
- Department of Medical Biometry and Epidemiology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - S Kuerti
- Department of Gynecology and Gynecologic Oncology, University Medical Center Hamburg-Eppendorf, Martinistraße 52, 20246, Hamburg, Germany
| | - S Reuter
- Department of Gynecology and Gynecologic Oncology, University Medical Center Hamburg-Eppendorf, Martinistraße 52, 20246, Hamburg, Germany
| | - J Dieckmann
- Department of Gynecology and Gynecologic Oncology, University Medical Center Hamburg-Eppendorf, Martinistraße 52, 20246, Hamburg, Germany
| | - B Schmalfeldt
- Department of Gynecology and Gynecologic Oncology, University Medical Center Hamburg-Eppendorf, Martinistraße 52, 20246, Hamburg, Germany
| | - L Woelber
- Department of Gynecology and Gynecologic Oncology, University Medical Center Hamburg-Eppendorf, Martinistraße 52, 20246, Hamburg, Germany.
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Bosse L, Mant BP, Schleier D, Gerlach M, Fischer I, Krueger A, Hemberger P, Worth G. Threshold Photoelectron Spectrum of Cyclobutadiene: Comparison with Time-Dependent Wavepacket Simulations. J Phys Chem Lett 2021; 12:6901-6906. [PMID: 34279954 DOI: 10.1021/acs.jpclett.1c01848] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
The C4H4 isomer cyclobutadiene (CBD) is the prime model for antiaromaticity and thus a molecule of considerable interest in chemistry. Because it is highly reactive, it can only be studied under isolated conditions. Its electronic structure is characterized by a pseudo-Jahn-Teller effect in the neutral and a E ⊗ β Jahn-Teller effect in the cation. As a result, recording photoelectron spectra as well as describing them theoretically has been challenging. Here we present the photoion mass-selected threshold photoelectron spectrum of cyclobutadiene together with a simulation based on time-dependent wavepacket dynamics that includes vibronic coupling in the ion, taking into account eight vibrational modes in the cation. Excellent agreement between theory and experiment is found, and the ionization energy is revised to 8.06 ± 0.02 eV.
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Affiliation(s)
- Lea Bosse
- Institute of Physical and Theoretical Chemistry, University of Würzburg, D-97074 Würzburg, Germany
| | - Barry P Mant
- Department of Chemistry, University College London, 20 Gordon St., London WC1H 0AJ, U.K
| | - Domenik Schleier
- Institute of Physical and Theoretical Chemistry, University of Würzburg, D-97074 Würzburg, Germany
| | - Marius Gerlach
- Institute of Physical and Theoretical Chemistry, University of Würzburg, D-97074 Würzburg, Germany
| | - Ingo Fischer
- Institute of Physical and Theoretical Chemistry, University of Würzburg, D-97074 Würzburg, Germany
| | - Anke Krueger
- Institute of Organic Chemistry, University of Würzburg, D-97074 Würzburg, Germany
| | - Patrick Hemberger
- Laboratory for Femtochemistry and Synchrotron Radiation, Paul Scherrer Institut (PSI), CH-5232 Villigen, Switzerland
| | - Graham Worth
- Department of Chemistry, University College London, 20 Gordon St., London WC1H 0AJ, U.K
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Ashfold M, Chergui M, Fischer I, Ge L, Grell G, Ivanov M, Kirrander A, Kornilov O, Krishnan SR, Küpper J, Kuttner C, Makhija V, Martín F, Matsika S, Minns RS, Natan A, Neumark DM, Palacios A, Pratt S, Röder A, Rost JM, Ruberti M, Stolow A, Titov E, Young L. Time-resolved ultrafast spectroscopy: general discussion. Faraday Discuss 2021; 228:329-348. [PMID: 33982724 DOI: 10.1039/d1fd90024b] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Jung JP, Haunstein K, Müller HH, Fischer I, Neff A. Intensive Care as an Independent Risk Factor for Infection after Reconstruction and Augmentation with Autologous Bone Grafts in Craniomaxillofacial Surgery: A Retrospective Cohort Study. J Clin Med 2021; 10:jcm10122560. [PMID: 34207893 PMCID: PMC8228131 DOI: 10.3390/jcm10122560] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2021] [Revised: 05/21/2021] [Accepted: 06/02/2021] [Indexed: 11/24/2022] Open
Abstract
Autologous bone grafts for reconstruction and augmentation are routinely used for maintaining functionality and facial aesthetics. Associated complications, however, have a significant impact on patients and health care systems. This study aims to investigate the possible risk factors associated with the occurrence of complications in order to provide evidence for the outcome of autologous bone graft reconstructive procedures. Patients from 2008 to 2018 who underwent autologous (mostly mandibular) reconstruction were included in the observational study. Clinical, pathological, and therapeutic factors were examined in univariate and multivariate analysis for significance with occurring complications. A multivariate model was used to create a prognostic model predicting the occurrence of complications. Graft complications requiring revision were exhibited by 33/128 patients. Infections were most frequent, with 4/22 patients affected by multi-resistant germs. Multivariate analysis showed radiotherapy (OR = 5.714; 95% CI: 1.839–17.752; p = 0.003), obstructive pulmonary disease (OPD) (OR = 4.329; 95% CI: 1.040–18.021; p = 0.044) and length of defect (in mm) (OR = 1.016; 95% CI: 1.004–1.028; p = 0.009) as independent risk factors associated with graft complications with high accuracy of prediction (AUC = 0.815). Intensive care (OR = 4.419; 95% CI: 1.576–12.388; p = 0.005) with a coefficient between intensive care and OPD (0.214) being low was identified as the most relevant risk factor for infection. Although intensive care is not a classic risk factor, but rather a summation of factors not reaching significance in the individual case, a stay in ICU (intensive care unit) needs to be considered for graft complications. As a clinical consequence, we recommend using the best possible hygienic measures during procedures e.g., while performing dressing and drainage changes in ICU.
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Affiliation(s)
- Jonas P. Jung
- Department of Oral and Maxillofacial Surgery, University of Marburg, Baldingerstrasse, D-35043 Marburg, Germany; (K.H.); (I.F.); (A.N.)
- Correspondence: ; Tel.: +49-151-282-554-31 or +49-6421-58-63237
| | - Kathrin Haunstein
- Department of Oral and Maxillofacial Surgery, University of Marburg, Baldingerstrasse, D-35043 Marburg, Germany; (K.H.); (I.F.); (A.N.)
| | - Hans-Helge Müller
- Institute of Medical Bioinformatics and Biostatistics, University of Marburg, Bunsenstrasse 3, D-35032 Marburg, Germany;
| | - Ingo Fischer
- Department of Oral and Maxillofacial Surgery, University of Marburg, Baldingerstrasse, D-35043 Marburg, Germany; (K.H.); (I.F.); (A.N.)
| | - Andreas Neff
- Department of Oral and Maxillofacial Surgery, University of Marburg, Baldingerstrasse, D-35043 Marburg, Germany; (K.H.); (I.F.); (A.N.)
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Ress L, Kaiser D, Grüne J, Gerlach M, Reusch E, Brixner T, Sperlich A, Engels B, Fischer I. Femtosecond dynamics of diphenylpropynylidene in ethanol and dichloromethane. Spectrochim Acta A Mol Biomol Spectrosc 2021; 254:119606. [PMID: 33740753 DOI: 10.1016/j.saa.2021.119606] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/01/2020] [Revised: 02/02/2021] [Accepted: 02/05/2021] [Indexed: 06/12/2023]
Abstract
Carbon chains with an odd number of C atoms are reactive intermediates with a high biradical character. Here we report a joint experimental and computational investigation of the dynamics of diphenylpropynylidene, C6H5-C3-C6H5, in dichloromethane and ethanol. The biradical is generated by ultraviolet light from 1,3-diphenyldiazopropyne. Electron paramagnetic resonance spectra are recorded to elucidate the spin multiplicity and geometry of the biradical. In both solvents a triplet ground state at 4 K is verified. Transient absorption spectra provide insight into the fate of the biradical. A study in deaerated dichloromethane permits us to follow the photophysics of diphenylpropynylidene and to extract time constants for its vibrational as well as electronic relaxation. In the presence of oxygen, a more complex photochemistry is observed that permits us to derive a model for the reaction of the biradical with O2. In ethanol, the spectra recorded in the presence and absence of O2 are very similar, which can be explained by the similarity of the chromophores of the reaction products.
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Affiliation(s)
- Lea Ress
- Institut für Physikalische und Theoretische Chemie, Universität Würzburg, Am Hubland, D-97074 Würzburg, Germany
| | - Dustin Kaiser
- Institut für Physikalische und Theoretische Chemie, Universität Würzburg, Am Hubland, D-97074 Würzburg, Germany
| | - Jeannine Grüne
- Fakultät für Physik, Universität of Würzburg, Am Hubland, D-97074 Würzburg, Germany
| | - Marius Gerlach
- Institut für Physikalische und Theoretische Chemie, Universität Würzburg, Am Hubland, D-97074 Würzburg, Germany
| | - Engelbert Reusch
- Institut für Physikalische und Theoretische Chemie, Universität Würzburg, Am Hubland, D-97074 Würzburg, Germany
| | - Tobias Brixner
- Institut für Physikalische und Theoretische Chemie, Universität Würzburg, Am Hubland, D-97074 Würzburg, Germany; Center for Nanosystems Chemistry (CNC), Universität Würzburg, Theodor-Boveri-Weg, 97074 Würzburg, Germany.
| | - Andreas Sperlich
- Fakultät für Physik, Universität of Würzburg, Am Hubland, D-97074 Würzburg, Germany.
| | - Bernd Engels
- Institut für Physikalische und Theoretische Chemie, Universität Würzburg, Am Hubland, D-97074 Würzburg, Germany.
| | - Ingo Fischer
- Institut für Physikalische und Theoretische Chemie, Universität Würzburg, Am Hubland, D-97074 Würzburg, Germany.
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Hofmann BB, Fischer I, Engel A, Jannusch K, Donaldson DM, Karadag C, van Lieshout JH, Beseoglu K, Muhammad S, Turowski B, Hänggi D, Kamp MA, Rubbert C. MTT Heterogeneity in Perfusion CT Imaging as a Predictor of Outcome after Aneurysmal SAH. AJNR Am J Neuroradiol 2021; 42:1387-1395. [PMID: 34083263 DOI: 10.3174/ajnr.a7169] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2021] [Accepted: 03/09/2021] [Indexed: 11/07/2022]
Abstract
BACKGROUND AND PURPOSE Impairment of tissue oxygenation caused by inhomogeneous microscopic blood flow distribution, the so-called capillary transit time heterogeneity, is thought to contribute to delayed cerebral ischemia after aneurysmal SAH but has so far not been systematically evaluated in patients. We hypothesized that heterogeneity of the MTT, derived from CTP parameters, would give insight into the clinical course of patients with aneurysmal SAH and may identify patients at risk of poor outcome. MATERIALS AND METHODS We retrospectively analyzed the heterogeneity of the MTT using the coefficient of variation in CTP scans from 132 patients. A multivariable logistic regression model was used to model the dichotomized mRS outcome. Linear regression was used to eliminate variables with high linear dependence. T tests were used to compare the means of 2 groups. Furthermore, the time of the maximum coefficient of variation for MTT after bleeding was evaluated for correlation with the mRS after 6 months. RESULTS On average, each patient underwent 5.3 CTP scans during his or her stay. Patients with high coefficient of variation for MTT presented more often with higher modified Fisher (P = .011) and World Federation of Neurosurgical Societies grades (P = .014). A high coefficient of variation for MTT at days 3-21 after aneurysmal SAH correlated significantly with a worse mRS score after 6 months (P = .016). We found no correlation between the time of the maximum coefficient of variation for MTT after bleeding and the patients' outcomes after 6 months (P = .203). CONCLUSIONS Heterogeneity of MTT in CTP after aneurysmal SAH correlates with the patients' outcomes. Because the findings are in line with the pathophysiologic concept of the capillary transit time heterogeneity, future studies should seek to verify the coefficient of variation for MTT as a potential imaging biomarker for outcome.
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Affiliation(s)
- B B Hofmann
- From the Department of Neurosurgery (B.B.H., I.F., A.E., D.M.D., C.K., J.H.v.L., K.B., S.M., D.H., M.A.K.), Medical Faculty, University Düsseldorf, Düsseldorf, Germany
| | - I Fischer
- From the Department of Neurosurgery (B.B.H., I.F., A.E., D.M.D., C.K., J.H.v.L., K.B., S.M., D.H., M.A.K.), Medical Faculty, University Düsseldorf, Düsseldorf, Germany
| | - A Engel
- From the Department of Neurosurgery (B.B.H., I.F., A.E., D.M.D., C.K., J.H.v.L., K.B., S.M., D.H., M.A.K.), Medical Faculty, University Düsseldorf, Düsseldorf, Germany
| | - K Jannusch
- Department of Diagnostic and Interventional Radiology (K.J., B.T., C.R.), Medical Faculty, University Düsseldorf, Düsseldorf, Germany
| | - D M Donaldson
- From the Department of Neurosurgery (B.B.H., I.F., A.E., D.M.D., C.K., J.H.v.L., K.B., S.M., D.H., M.A.K.), Medical Faculty, University Düsseldorf, Düsseldorf, Germany
| | - C Karadag
- Medical Faculty (C.K.), University Düsseldorf, Düsseldorf, Germany
| | - J H van Lieshout
- From the Department of Neurosurgery (B.B.H., I.F., A.E., D.M.D., C.K., J.H.v.L., K.B., S.M., D.H., M.A.K.), Medical Faculty, University Düsseldorf, Düsseldorf, Germany
| | - K Beseoglu
- From the Department of Neurosurgery (B.B.H., I.F., A.E., D.M.D., C.K., J.H.v.L., K.B., S.M., D.H., M.A.K.), Medical Faculty, University Düsseldorf, Düsseldorf, Germany
| | - S Muhammad
- From the Department of Neurosurgery (B.B.H., I.F., A.E., D.M.D., C.K., J.H.v.L., K.B., S.M., D.H., M.A.K.), Medical Faculty, University Düsseldorf, Düsseldorf, Germany
| | - B Turowski
- Department of Diagnostic and Interventional Radiology (K.J., B.T., C.R.), Medical Faculty, University Düsseldorf, Düsseldorf, Germany
| | - D Hänggi
- From the Department of Neurosurgery (B.B.H., I.F., A.E., D.M.D., C.K., J.H.v.L., K.B., S.M., D.H., M.A.K.), Medical Faculty, University Düsseldorf, Düsseldorf, Germany
| | - M A Kamp
- From the Department of Neurosurgery (B.B.H., I.F., A.E., D.M.D., C.K., J.H.v.L., K.B., S.M., D.H., M.A.K.), Medical Faculty, University Düsseldorf, Düsseldorf, Germany
| | - C Rubbert
- Department of Diagnostic and Interventional Radiology (K.J., B.T., C.R.), Medical Faculty, University Düsseldorf, Düsseldorf, Germany
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Allum F, Amini K, Ashfold M, Bansal D, Berger RJF, Centurion M, Dixit G, Durham D, Fasshauer E, Figueira Nunes JP, Fischer I, Grell G, Ivanov M, Kirrander A, Kornilov O, Kuttner C, Lopata K, Ma L, Makhija V, Maxwell A, Moreno Carrascosa A, Natan A, Neumark D, Pratt S, Röder A, Rolles D, Rost JM, Sekikawa T, Simmermacher M, Stolow A, Titov E, Tremblay JC, Weber PM, Yong H, Young L. Time-resolved diffraction: general discussion. Faraday Discuss 2021; 228:161-190. [PMID: 33982708 DOI: 10.1039/d1fd90023d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Allum F, Calegari F, Cavaletto SM, Centurion M, Dixit G, Fasshauer E, Fischer I, Forbes R, Grell G, Ivanov M, Kirrander A, Kornilov O, Küpper J, Kuttner C, Marangos J, Matsika S, Maxwell A, Minns RS, Moreno Carrascosa A, Natan A, Neumark D, Odate A, Oyarzún A, Palacios A, Pfeifer T, Röder A, Rost JM, Rouzée A, Stolow A, Titov E, Weber PM, Wolf T. Ultrafast X-ray science: general discussion. Faraday Discuss 2021; 228:597-621. [PMID: 33978014 DOI: 10.1039/d1fd90026a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Pariz A, Fischer I, Valizadeh A, Mirasso C. Transmission delays and frequency detuning can regulate information flow between brain regions. PLoS Comput Biol 2021; 17:e1008129. [PMID: 33857135 PMCID: PMC8049288 DOI: 10.1371/journal.pcbi.1008129] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2020] [Accepted: 02/16/2021] [Indexed: 12/28/2022] Open
Abstract
Brain networks exhibit very variable and dynamical functional connectivity and flexible configurations of information exchange despite their overall fixed structure. Brain oscillations are hypothesized to underlie time-dependent functional connectivity by periodically changing the excitability of neural populations. In this paper, we investigate the role of the connection delay and the detuning between the natural frequencies of neural populations in the transmission of signals. Based on numerical simulations and analytical arguments, we show that the amount of information transfer between two oscillating neural populations could be determined by their connection delay and the mismatch in their oscillation frequencies. Our results highlight the role of the collective phase response curve of the oscillating neural populations for the efficacy of signal transmission and the quality of the information transfer in brain networks.
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Affiliation(s)
- Aref Pariz
- Department of Physics, Institute for Advanced Studies in Basic Sciences (IASBS), Zanjan, Iran
- Instituto de Física Interdisciplinar y Sistemas Complejos IFISC (UIB-CSIC), Campus Universitat de les Illes Balears, Palma de Mallorca, Spain
| | - Ingo Fischer
- Instituto de Física Interdisciplinar y Sistemas Complejos IFISC (UIB-CSIC), Campus Universitat de les Illes Balears, Palma de Mallorca, Spain
| | - Alireza Valizadeh
- Department of Physics, Institute for Advanced Studies in Basic Sciences (IASBS), Zanjan, Iran
- School of biological sciences, Institute for research in fundamental sciences (IPM), Tehran, Iran
- * E-mail: (AV); (CM)
| | - Claudio Mirasso
- Instituto de Física Interdisciplinar y Sistemas Complejos IFISC (UIB-CSIC), Campus Universitat de les Illes Balears, Palma de Mallorca, Spain
- * E-mail: (AV); (CM)
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Matthaei CT, Mukhopadhyay DP, Fischer I. Photodissociation of Benzoyl Chloride: A Velocity Map Imaging Study Using VUV Detection of Chlorine Atoms. J Phys Chem A 2021; 125:2816-2825. [PMID: 33819043 DOI: 10.1021/acs.jpca.0c11236] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
UV photodissociation of benzoyl chloride, Ph-CO-Cl, is associated with the loss of a chlorine atom. Here we excite benzoyl chloride to the S1, S2, and S3 excited states at 237, 253, 265, and 279.6 nm and detect the Cl photofragment by [1 + 1'] photoionization using 118.9 nm VUV radiation. The translational energy distribution of the Cl atom is measured by velocity map ion imaging. An isotropic image and a unimodal translational energy distribution are observed at all dissociation wavelengths, and a fraction of 18-20% of the excess energy is released into translation. The results indicate a dissociation that predominately proceeds from the vibrationally hot S0 ground state, although the observed translational energy release deviates significantly from a prior distribution. However, the impulsive model does also not represent the translational energy release. As a Cl/Cl* branching ratio of 9:1 or more is observed in one-color experiments at 235 nm, we conclude that direct dissociation from excited electronic states contributes only to a minor extent.
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Affiliation(s)
- Christian T Matthaei
- Institute of Physical and Theoretical Chemistry, University of Würzburg, Am Hubland, D-97074 Würzburg, Germany
| | - Deb Pratim Mukhopadhyay
- Institute of Physical and Theoretical Chemistry, University of Würzburg, Am Hubland, D-97074 Würzburg, Germany
| | - Ingo Fischer
- Institute of Physical and Theoretical Chemistry, University of Würzburg, Am Hubland, D-97074 Würzburg, Germany
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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] [What about the content of this article? (0)] [Affiliation(s)] [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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Affiliation(s)
- Ingo Fischer
- Instituto de Física Interdisciplinar y Sistemas Complejos (IFISC), Consejo Superior de Investigaciones Científicas-Universitat de las Islas Baleares (CSIC-UIB), Campus Universitat de les Illes Balears, E-07122 Palma de Mallorca, Spain.
| | - Daniel J Gauthier
- Department of Physics, Ohio State University, Columbus, OH 43210, USA.
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Valencia RG, Mihailovska E, Winter L, Bauer K, Fischer I, Walko G, Jorgacevski J, Potokar M, Zorec R, Wiche G. Plectin dysfunction in neurons leads to tau accumulation on microtubules affecting neuritogenesis, organelle trafficking, pain sensitivity and memory. Neuropathol Appl Neurobiol 2021; 47:73-95. [PMID: 32484610 PMCID: PMC7891324 DOI: 10.1111/nan.12635] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2019] [Accepted: 05/19/2020] [Indexed: 12/26/2022]
Abstract
AIMS Plectin, a universally expressed multi-functional cytolinker protein, is crucial for intermediate filament networking, including crosstalk with actomyosin and microtubules. In addition to its involvement in a number of diseases affecting skin, skeletal muscle, heart, and other stress-exposed tissues, indications for a neuropathological role of plectin have emerged. Having identified P1c as the major isoform expressed in neural tissues in previous studies, our aim for the present work was to investigate whether, and by which mechanism(s), the targeted deletion of this isoform affects neuritogenesis and proper nerve cell functioning. METHODS For ex vivo phenotyping, we used dorsal root ganglion and hippocampal neurons derived from isoform P1c-deficient and plectin-null mice, complemented by in vitro experiments using purified proteins and cell fractions. To assess the physiological significance of the phenotypic alterations observed in P1c-deficient neurons, P1c-deficient and wild-type littermate mice were subjected to standard behavioural tests. RESULTS We demonstrate that P1c affects axonal microtubule dynamics by isoform-specific interaction with tubulin. P1c deficiency in neurons leads to altered dynamics of microtubules and excessive association with tau protein, affecting neuritogenesis, neurite branching, growth cone morphology, and translocation and directionality of movement of vesicles and mitochondria. On the organismal level, we found P1c deficiency manifesting as impaired pain sensitivity, diminished learning capabilities and reduced long-term memory of mice. CONCLUSIONS Revealing a regulatory role of plectin scaffolds in microtubule-dependent nerve cell functions, our results have potential implications for cytoskeleton-related neuropathies.
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Affiliation(s)
- R. G. Valencia
- Max F. Perutz LaboratoriesDepartment of Biochemistry and Cell BiologyUniversity of ViennaViennaAustria
- Present address:
Department of ImmunologyUniversity Children’s Hospital ZurichZurichSwitzerland
| | - E. Mihailovska
- Max F. Perutz LaboratoriesDepartment of Biochemistry and Cell BiologyUniversity of ViennaViennaAustria
- Present address:
AFFiRiS AGViennaAustria
| | - L. Winter
- Max F. Perutz LaboratoriesDepartment of Biochemistry and Cell BiologyUniversity of ViennaViennaAustria
- Neuromuscular Research DepartmentCenter for Anatomy and Cell BiologyMedical University of ViennaViennaAustria
| | - K. Bauer
- Max F. Perutz LaboratoriesDepartment of Biochemistry and Cell BiologyUniversity of ViennaViennaAustria
| | - I. Fischer
- Max F. Perutz LaboratoriesDepartment of Biochemistry and Cell BiologyUniversity of ViennaViennaAustria
| | - G. Walko
- Max F. Perutz LaboratoriesDepartment of Biochemistry and Cell BiologyUniversity of ViennaViennaAustria
- Present address:
Department of Biology and BiochemistryUniversity of BathBathUK
| | - J. Jorgacevski
- Laboratory of Neuroendocrinology – Molecular Cell PhysiologyFaculty of MedicineInstitute of PathophysiologyUniversity of LjubljanaLjubljanaSlovenia
- Celica Biomedical SloveniaLjubljanaSlovenia
| | - M. Potokar
- Laboratory of Neuroendocrinology – Molecular Cell PhysiologyFaculty of MedicineInstitute of PathophysiologyUniversity of LjubljanaLjubljanaSlovenia
- Celica Biomedical SloveniaLjubljanaSlovenia
| | - R. Zorec
- Laboratory of Neuroendocrinology – Molecular Cell PhysiologyFaculty of MedicineInstitute of PathophysiologyUniversity of LjubljanaLjubljanaSlovenia
- Celica Biomedical SloveniaLjubljanaSlovenia
| | - G. Wiche
- Max F. Perutz LaboratoriesDepartment of Biochemistry and Cell BiologyUniversity of ViennaViennaAustria
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Schleier D, Reusch E, Gerlach M, Preitschopf T, Mukhopadhyay DP, Faßheber N, Friedrichs G, Hemberger P, Fischer I. Kinetics of 1- and 2-methylallyl + O 2 reaction, investigated by photoionisation using synchrotron radiation. Phys Chem Chem Phys 2021; 23:1539-1549. [PMID: 33404571 DOI: 10.1039/d0cp05441k] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The reaction kinetics of the isomers of the methylallyl radical with molecular oxygen has been studied in a flow tube reactor at the vacuum ultraviolet (VUV) beamline of the Swiss Light Source storage ring. The radicals were generated by direct photodissociation of bromides or iodides at 213 nm. Experiments were conducted at room temperature and low pressures between 1 and 3 mbar using He as the buffer gas. Oxygen was employed in excess to maintain near pseudo-first-order reaction conditions. Concentration-time profiles of the radical were monitored by photoionisation. For the oxidation of 2-methylallyl (2-MA) and with k(2-MA + O2) = (5.1 ± 1.0) × 1011 cm3 mol-1 s-1, the rate constant was found to be in the high-pressure limit already at 1 mbar. In contrast, 1-methylallyl exists in two isomers, E- and Z-1-methylallyl. We selectively detected the E-conformer as well as a mixture of both isomers and observed almost identical rate constants within the uncertainty of the experiment. A small pressure dependence is observed with the rate constant increasing from k(1-MA + O2) = (3.5 ± 0.7) × 1011 cm3 mol-1 s-1 at 1 mbar to k(1-MA + O2) = (4.6 ± 0.9) × 1011 cm3 mol-1 s-1 at 3 mbar. While for 2-methylallyl + O2 no previous experimental data are available, the rate constants for 1-methylallyl are in agreement with previous work. A comparison is drawn for the trends of the high-pressure limiting rate constants and pressure dependences observed for the O2 recombination of allylic radicals with the corresponding reactions of alkyl radicals.
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Affiliation(s)
- Domenik Schleier
- Institute of Physical and Theoretical Chemistry, University of Würzburg, Am Hubland, D-97074 Würzburg, Germany.
| | - Engelbert Reusch
- Institute of Physical and Theoretical Chemistry, University of Würzburg, Am Hubland, D-97074 Würzburg, Germany.
| | - Marius Gerlach
- Institute of Physical and Theoretical Chemistry, University of Würzburg, Am Hubland, D-97074 Würzburg, Germany.
| | - Tobias Preitschopf
- Institute of Physical and Theoretical Chemistry, University of Würzburg, Am Hubland, D-97074 Würzburg, Germany.
| | - Deb Pratim Mukhopadhyay
- Institute of Physical and Theoretical Chemistry, University of Würzburg, Am Hubland, D-97074 Würzburg, Germany.
| | - Nancy Faßheber
- Institute of Physical Chemistry, Christian-Albrechts-University Kiel, Max-Eyth-Str. 1, D-24118 Kiel, Germany.
| | - Gernot Friedrichs
- Institute of Physical Chemistry, Christian-Albrechts-University Kiel, Max-Eyth-Str. 1, D-24118 Kiel, Germany.
| | - Patrick Hemberger
- Laboratory for Femtochemistry and Synchrotron Radiation, Paul Scherrer Institut (PSI), CH-5232 Villigen, Switzerland.
| | - Ingo Fischer
- Institute of Physical and Theoretical Chemistry, University of Würzburg, Am Hubland, D-97074 Würzburg, Germany.
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Schmitt HC, Fischer I, Ji L, Merz J, Marder TB, Hoche J, Röhr MIS, Mitric R. Isolated 2-hydroxypyrene and its dimer: a frequency- and time-resolved spectroscopic study. NEW J CHEM 2021. [DOI: 10.1039/d0nj02391d] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We investigated isolated 2-hydroxypyrene and its dimer in the gas phase by time- and frequency-resolved photoionisation with picosecond time-resolution.
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Affiliation(s)
- Hans-Christian Schmitt
- Institut für Physikalische und Theoretische Chemie, Julius-Maximilians-Universität Würzburg, D-97074 Würzburg, Germany
| | - Ingo Fischer
- Institut für Physikalische und Theoretische Chemie, Julius-Maximilians-Universität Würzburg, D-97074 Würzburg, Germany
| | - Lei Ji
- Institut für Anorganische Chemie, and Institute for Sustainable Chemistry & Catalysis with Boron, Julius-Maximilians-Universität Würzburg, D-97074 Würzburg, Germany
| | - Julia Merz
- Institut für Anorganische Chemie, and Institute for Sustainable Chemistry & Catalysis with Boron, Julius-Maximilians-Universität Würzburg, D-97074 Würzburg, Germany
| | - Todd B. Marder
- Institut für Anorganische Chemie, and Institute for Sustainable Chemistry & Catalysis with Boron, Julius-Maximilians-Universität Würzburg, D-97074 Würzburg, Germany
| | - Joscha Hoche
- Institut für Physikalische und Theoretische Chemie, Julius-Maximilians-Universität Würzburg, D-97074 Würzburg, Germany
| | - Merle I. S. Röhr
- Institut für Physikalische und Theoretische Chemie, Julius-Maximilians-Universität Würzburg, D-97074 Würzburg, Germany
- Center for Nanosystems Chemistry (CNC), Julius-Maximilians-Universität Würzburg, Theodor-Boveri-Weg, D-97074 Würzburg, Germany
| | - Roland Mitric
- Institut für Physikalische und Theoretische Chemie, Julius-Maximilians-Universität Würzburg, D-97074 Würzburg, Germany
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