1
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Limbach MN, Do TD. Solvent-Free Nuclear Magnetic Resonance Spectroscopy of Charged Molecules. J Phys Chem A 2023; 127:9149-9157. [PMID: 37861438 DOI: 10.1021/acs.jpca.3c05241] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2023]
Abstract
Nuclear magnetic resonance (NMR) spectroscopy of small molecules protonated in a solvent-free environment was successfully demonstrated. The method is referred to as solvent-free protonation NMR (SoF-NMR). Leveraging matrix-assisted ionization (MAI), we generated protonated species of aniline, 4-chloroaniline, 4-aminobiphenyl, and benzocaine for NMR analysis under mild pressure and temperature conditions. The SoF-NMR spectra were compared to traditional solution NMR spectra, and the shift changes in nuclear spin resonance frequencies verify that these small molecules are protonated by 3-nitrobenzonitrile (3-NBN). As the sample pressure decreased, new spectral features appeared, indicating the presence of differently charged species. Several advantages of SoF-NMR are highlighted, such as the elimination of H/D exchange in labile protons, resulting in the precise observation of protons that are otherwise transient in solution. Notably, the data on benzocaine show evidence of neutral, N-protonated, and O-protonated species all in the same spectrum. SoF-NMR eliminates the solvent effects and interactions that can hinder important spectral features. Optimizing SoF-NMR will result in more cost-effective and efficient NMR experimentation to monitor high-temperature, solvent-free reactions. SoF-NMR has a viable future application for studying exchangeable protons, intermediates, and products in gas-phase chemistry.
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Affiliation(s)
- Miranda N Limbach
- Department of Chemistry, University of Tennessee, Knoxville, Tennessee 37996, United States
| | - Thanh D Do
- Department of Chemistry, University of Tennessee, Knoxville, Tennessee 37996, United States
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2
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Rouquet E, Roy Chowdhury M, Garcia GA, Nahon L, Dupont J, Lepère V, Le Barbu-Debus K, Zehnacker A. Induced photoelectron circular dichroism onto an achiral chromophore. Nat Commun 2023; 14:6290. [PMID: 37813848 PMCID: PMC10562374 DOI: 10.1038/s41467-023-42002-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2023] [Accepted: 09/25/2023] [Indexed: 10/11/2023] Open
Abstract
An achiral chromophore can acquire a chiral spectroscopic signature when interacting with a chiral environment. This so-called induced chirality is documented in electronic or vibrational circular dichroism, which arises from the coupling between electric and magnetic transition dipoles. Here, we demonstrate that a chiroptical response is also induced within the electric dipole approximation by observing the asymmetric scattering of a photoelectron ejected from an achiral chromophore in interaction with a chiral host. In a phenol-methyloxirane complex, removing an electron from an achiral aromatic π orbital localised on the phenol moiety results in an intense and opposite photoelectron circular dichroism (PECD) for the two enantiomeric complexes with (R) and (S) methyloxirane, evidencing the long-range effect (~5 Å) of the scattering chiral potential. This induced chirality has important structural and analytical implications, discussed here in the context of growing interest in laser-based PECD, for in situ, real time enantiomer determination.
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Affiliation(s)
- Etienne Rouquet
- Synchrotron SOLEIL, L'Orme des Merisiers, Départementale 128, F-91190, St Aubin, France
- Institut des Sciences Moléculaires d'Orsay (ISMO), CNRS, Université Paris-Saclay, F-91405, Orsay, France
| | | | - Gustavo A Garcia
- Synchrotron SOLEIL, L'Orme des Merisiers, Départementale 128, F-91190, St Aubin, France
| | - Laurent Nahon
- Synchrotron SOLEIL, L'Orme des Merisiers, Départementale 128, F-91190, St Aubin, France.
| | - Jennifer Dupont
- Institut des Sciences Moléculaires d'Orsay (ISMO), CNRS, Université Paris-Saclay, F-91405, Orsay, France
| | - Valéria Lepère
- Institut des Sciences Moléculaires d'Orsay (ISMO), CNRS, Université Paris-Saclay, F-91405, Orsay, France
| | - Katia Le Barbu-Debus
- Institut des Sciences Moléculaires d'Orsay (ISMO), CNRS, Université Paris-Saclay, F-91405, Orsay, France
| | - Anne Zehnacker
- Institut des Sciences Moléculaires d'Orsay (ISMO), CNRS, Université Paris-Saclay, F-91405, Orsay, France.
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3
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Sparling C, Crane SW, Ireland L, Anderson R, Ghafur O, Greenwood JB, Townsend D. Velocity-map imaging of photoelectron circular dichroism in non-volatile molecules using a laser-based desorption source. Phys Chem Chem Phys 2023; 25:6009-6015. [PMID: 36752555 DOI: 10.1039/d2cp05880d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/09/2023]
Abstract
We present an initial demonstration of a velocity-map imaging (VMI) experiment using a back-irradiation laser-based desorption source directly integrated into the electrode assembly. This has the potential to greatly expand the utility of the popular VMI approach by permitting its use with high density plumes of non-volatile molecular samples. Photoelectron circular dichroism measurements on the phenylalanine molecule using 400 nm multiphoton ionization are used to illustrate this novel method, revealing forward-backward emission asymmetries on the order of 7%.
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Affiliation(s)
- Chris Sparling
- Institute of Photonics & Quantum Sciences, Heriot-Watt University, Edinburgh, EH14 4AS, UK.
| | - Stuart W Crane
- Institute of Photonics & Quantum Sciences, Heriot-Watt University, Edinburgh, EH14 4AS, UK.
| | - Lewis Ireland
- Institute of Photonics & Quantum Sciences, Heriot-Watt University, Edinburgh, EH14 4AS, UK.
| | - Ross Anderson
- Institute of Photonics & Quantum Sciences, Heriot-Watt University, Edinburgh, EH14 4AS, UK.
| | - Omair Ghafur
- Institute of Photonics & Quantum Sciences, Heriot-Watt University, Edinburgh, EH14 4AS, UK.
| | - Jason B Greenwood
- School of Mathematics and Physics, Queen's University Belfast, Belfast, BT7 1NN, UK
| | - Dave Townsend
- Institute of Photonics & Quantum Sciences, Heriot-Watt University, Edinburgh, EH14 4AS, UK. .,Institute of Chemical Sciences, Heriot-Watt University, Edinburgh, EH14 4AS, UK
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4
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Triptow J, Fielicke A, Meijer G, Green M. Imaging Photoelectron Circular Dichroism in the Detachment of Mass-Selected Chiral Anions. Angew Chem Int Ed Engl 2023; 62:e202212020. [PMID: 36201361 PMCID: PMC10099851 DOI: 10.1002/anie.202212020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2022] [Indexed: 12/05/2022]
Abstract
Photoelectron Circular Dichroism (PECD) is a forward-backward asymmetry in the photoemission from a non-racemic sample induced by circularly polarized light. PECD spectroscopy has potential analytical advantages for chiral discrimination over other chiroptical methods due to its increased sensitivity to the chiral potential of the molecule. The use of anions for PECD spectroscopy allows for mass-selectivity and provides a path to simple experimental schemes that employ table-top light sources. Evidence of PECD for anions is limited, and insight into the forces that govern PECD electron dynamics in photodetachment is absent. Here, we demonstrate a PECD effect in the photodetachment of mass-selected deprotonated 1-indanol anions. By utilizing velocity map imaging photoelectron spectroscopy with a tunable light source, we determine the energy-resolved PECD over a wide range of photon energies. The observed PECD reaches up to 11 %, similar to what has been measured for neutral species.
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Affiliation(s)
- Jenny Triptow
- Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, 14195, Berlin, Germany
| | - André Fielicke
- Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, 14195, Berlin, Germany
| | - Gerard Meijer
- Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, 14195, Berlin, Germany
| | - Mallory Green
- Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, 14195, Berlin, Germany
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5
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Ayuso D, Ordonez AF, Smirnova O. Ultrafast chirality: the road to efficient chiral measurements. Phys Chem Chem Phys 2022; 24:26962-26991. [PMID: 36342056 PMCID: PMC9673685 DOI: 10.1039/d2cp01009g] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2022] [Accepted: 07/20/2022] [Indexed: 08/20/2023]
Abstract
Today we are witnessing the electric-dipole revolution in chiral measurements. Here we reflect on its lessons and outcomes, such as the perspective on chiral measurements using the complementary principles of "chiral reagent" and "chiral observer", the hierarchy of scalar, vectorial and tensorial enantio-sensitive observables, the new properties of the chiro-optical response in the ultrafast and non-linear domains, and the geometrical magnetism associated with the chiral response in photoionization. The electric-dipole revolution is a landmark event. It has opened routes to extremely efficient enantio-discrimination with a family of new methods. These methods are governed by the same principles but work in vastly different regimes - from microwaves to optical light; they address all molecular degrees of freedom - electronic, vibrational and rotational, and use flexible detection schemes, i.e. detecting photons or electrons, making them applicable to different chiral phases, from gases to liquids to amorphous solids. The electric-dipole revolution has also enabled enantio-sensitive manipulation of chiral molecules with light. This manipulation includes exciting and controlling ultrafast helical currents in vibronic states of chiral molecules, enantio-sensitive control of populations in electronic, vibronic and rotational molecular states, and opens the way to efficient enantio-separation and enantio-sensitive trapping of chiral molecules. The word "perspective" has two meanings: an "outlook" and a "point of view". In this perspective article, we have tried to cover both meanings.
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Affiliation(s)
- David Ayuso
- Max-Born-Institut, 12489 Berlin, Germany
- Imperial College London, SW7 2AZ London, UK.
| | - Andres F Ordonez
- Max-Born-Institut, 12489 Berlin, Germany
- ICFO-Institut de Ciencies Fotoniques, The Barcelona Institute of Science and Technology, 08860 Barcelona, Spain.
| | - Olga Smirnova
- Max-Born-Institut, 12489 Berlin, Germany
- Technische Universität Berlin, 10623 Berlin, Germany.
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6
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Bolognesi P, Avaldi L. Photoelectron-photoion(s) coincidence studies of molecules of biological interest. Phys Chem Chem Phys 2022; 24:22356-22370. [PMID: 36124990 DOI: 10.1039/d2cp03079a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Photoelectron-photoion(s) coincidence, PEPICO, experiments with synchrotron radiation have become one of the most powerful tools to investigate dissociative photoionization thanks to their selectivity. In this paper their application to the study of molecular species of biological interest in the gas phase is reviewed. Some applications of PEPICO to the study of potential radiosensitizers, amino acids and small peptides and opportunities offered by the advent of novel methods for the production of beams of these molecules are discussed.
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Affiliation(s)
- P Bolognesi
- CNR-Istituto di Struttura della Materia, Area della Ricerca di Roma 1, CP 10 00015 Monterotondo Scalo, Italy.
| | - L Avaldi
- CNR-Istituto di Struttura della Materia, Area della Ricerca di Roma 1, CP 10 00015 Monterotondo Scalo, Italy.
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7
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Krüger P, Both JH, Linne U, Chirot F, Weitzel KM. Photoelectron Circular Dichroism of Electrosprayed Gramicidin Anions. J Phys Chem Lett 2022; 13:6110-6116. [PMID: 35759344 DOI: 10.1021/acs.jpclett.2c01437] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Many sophisticated approaches for analyzing properties of chiral matter have been developed in recent years. But in general, the available chiroptical methods are limited to either solvated or small gaseous molecules. Studying the chirality of large biopolymers in the gas phase, including aspects of the secondary structure, becomes accessible by combining the electrospray ionization technique with chiroptical detection protocols. Here, laser-induced photodetachment from gramicidin anions, a peptide consisting of 15 amino acids has been investigated. The angular distribution of photoelectrons is demonstrated to be sensitive to the substitution of protons by cesium ions, which is accompanied by a conformational change. The photoelectron circular dichroism (PECD) is -0.5% for bare gramicidin, whereas gramicidin with several Cs+ ions attached exhibits a PECD of +0.5%. The results are complemented and supported by ion mobility studies. The presented approach offers the prospect of studying chirality and the secondary structure of various biopolymers.
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Affiliation(s)
- Peter Krüger
- Department of Chemistry, Philipps-Universität Marburg, Hans-Meerwein-Straße, 35043 Marburg, Germany
| | - Jon Henrik Both
- Department of Chemistry, Philipps-Universität Marburg, Hans-Meerwein-Straße, 35043 Marburg, Germany
| | - Uwe Linne
- Department of Chemistry, Philipps-Universität Marburg, Hans-Meerwein-Straße, 35043 Marburg, Germany
| | - Fabien Chirot
- Institut Lumière Matière, UMR5306 Université de Lyon, Université Lyon 1, CNRS, 5 rue de la Doua, 69100 Villeurbanne, France
| | - Karl-Michael Weitzel
- Department of Chemistry, Philipps-Universität Marburg, Hans-Meerwein-Straße, 35043 Marburg, Germany
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8
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Artemyev AN, Kutscher E, Demekhin PV. Photoelectron circular dichroism of a model chiral anion. J Chem Phys 2022; 156:031101. [DOI: 10.1063/5.0079723] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Anton N. Artemyev
- Institut für Physik und CINSaT, Universität Kassel, Heinrich-Plett-Str. 40, 34132 Kassel, Germany
| | - Eric Kutscher
- Institut für Physik und CINSaT, Universität Kassel, Heinrich-Plett-Str. 40, 34132 Kassel, Germany
| | - Philipp V. Demekhin
- Institut für Physik und CINSaT, Universität Kassel, Heinrich-Plett-Str. 40, 34132 Kassel, Germany
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9
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Yuan DF, Zhang YR, Qian CH, Wang LS. Resonant two-photon photoelectron imaging and adiabatic detachment processes from bound vibrational levels of dipole-bound states. Phys Chem Chem Phys 2022; 24:1380-1389. [PMID: 34981094 DOI: 10.1039/d1cp05219e] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Anions cannot have Rydberg states, but anions with polar neutral cores can support highly diffuse dipole-bound states (DBSs) as a class of interesting electronically excited states below the electron detachment threshold. The binding energies of DBSs are extremely small, ranging from a few to few hundred wavenumbers and generally cannot support bound vibrational levels below the detachment threshold. Thus, vibrational excitations in the DBS are usually above the electron detachment threshold and they have been used to conduct resonant photoelectron spectroscopy, which is dominated by state-specific autodetachment. Here we report an investigation of a cryogenically-cooled complex anion, the enantiopure (R)-(-)-1-(9-anthryl)-2,2,2-trifluoroethanolate (R-TFAE-). The neutral R-TFAE radical is relatively complex and highly polar with a non-planar structure (C1 symmetry). Photodetachment spectroscopy reveals a DBS 209 cm-1 below the detachment threshold of R-TFAE- and seven bound and eight above-threshold vibrational levels of the DBS. Resonant two-photon detachment (R2PD) via the bound vibrational levels of the DBS exhibits strictly adiabatic photodetachment behaviors by the second photon, in which the vibrational energies in the DBS are carried to the neutral final states, because of the parallel potential energy surfaces of the DBS and the corresponding neutral ground electronic state. Relaxation processes from the bound DBS levels to the ground and low-lying electronically excited states of R-TFAE- are also observed in the R2PD photoelectron spectra. The combination of photodetachment and resonant photoelectron spectroscopy yields frequencies for eight vibrational modes of the R-TFAE radical.
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Affiliation(s)
- Dao-Fu Yuan
- Department of Chemsitry, Brown University, Providence, RI 02912, USA.
| | - Yue-Rou Zhang
- Department of Chemsitry, Brown University, Providence, RI 02912, USA.
| | - Chen-Hui Qian
- Department of Chemsitry, Brown University, Providence, RI 02912, USA.
| | - Lai-Sheng Wang
- Department of Chemsitry, Brown University, Providence, RI 02912, USA.
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10
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Ranecky ST, Park GB, Samartzis PC, Giannakidis IC, Schwarzer D, Senftleben A, Baumert T, Schäfer T. Detecting chirality in mixtures using nanosecond photoelectron circular dichroism. Phys Chem Chem Phys 2022; 24:2758-2761. [PMID: 35044414 DOI: 10.1039/d1cp05468f] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We report chirality detection of structural isomers in a gas phase mixture using nanosecond photoelectron circular dichroism (PECD). Combining pulsed molecular beams with high-resolution resonance enhanced multi-photon ionization (REMPI) allows specific isolated transitions belonging to distinct components in the mixture to be targeted.
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Affiliation(s)
- Simon T Ranecky
- Universität Kassel, Heinrich-Plett-Str. 40, Kassel 34132, Germany
| | - G Barratt Park
- Georg-August-Universität Göttingen, Tammannstr. 6, Göttingen 37077, Germany. .,Max Planck Institut für Biophysikalische Chemie, Am Fassberg 11, Göttingen 37077, Germany.,Department of Chemistry and Biochemistry, Texas Tech University, Box 41061, Lubbock, TX 79409-1061, USA
| | - Peter C Samartzis
- Institute of Electronic Structure and Lasers, Foundation for Research and Technology - Hellas (FORTH), P. O. Box 1527, Heraklion 71110, Greece
| | - Ioannis C Giannakidis
- Institute of Electronic Structure and Lasers, Foundation for Research and Technology - Hellas (FORTH), P. O. Box 1527, Heraklion 71110, Greece.,Department of Materials Science and Technology, University of Crete, Heraklion 71003, Greece
| | - Dirk Schwarzer
- Max Planck Institut für Biophysikalische Chemie, Am Fassberg 11, Göttingen 37077, Germany
| | - Arne Senftleben
- Universität Kassel, Heinrich-Plett-Str. 40, Kassel 34132, Germany
| | - Thomas Baumert
- Universität Kassel, Heinrich-Plett-Str. 40, Kassel 34132, Germany
| | - Tim Schäfer
- Georg-August-Universität Göttingen, Tammannstr. 6, Göttingen 37077, Germany. .,Max Planck Institut für Biophysikalische Chemie, Am Fassberg 11, Göttingen 37077, Germany
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11
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Lehmann CS, Botros D, Weitzel KM. Coincident measurement of photo-ion circular dichroism and photo-electron circular dichroism on 1-Phenylethylamine. Phys Chem Chem Phys 2022; 24:15904-15911. [DOI: 10.1039/d2cp01418a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Here we report the coincident measurement of the PICD and PECD effect in 1-Phenylethylamine upon multiphoton ionisation. Photo-ion circular dichroism (PICD) and photo-electron circular dichroism (PECD) are both methods to...
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12
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Lee HG, Ranecky ST, Vasudevan S, Ladda N, Rosen T, Das S, Ghosh J, Braun H, Reich DM, Senftleben A, Baumert T. Pulse length dependence of photoelectron circular dichroism. Phys Chem Chem Phys 2022; 24:27483-27494. [DOI: 10.1039/d2cp03202c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
We investigated photoelectron circular dichroism (PECD) using pulses with various durations. From the experiment with fenchone, we found constancy of the PECD over a wide range of pulse durations and estimated lifetimes of internal conversions.
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Affiliation(s)
- Han-gyeol Lee
- Institut für Physik, Universität Kassel, Heinrich-Plett-Str. 40, 34132 Kassel, Germany
| | - Simon T. Ranecky
- Institut für Physik, Universität Kassel, Heinrich-Plett-Str. 40, 34132 Kassel, Germany
| | - Sudheendran Vasudevan
- Institut für Physik, Universität Kassel, Heinrich-Plett-Str. 40, 34132 Kassel, Germany
| | - Nicolas Ladda
- Institut für Physik, Universität Kassel, Heinrich-Plett-Str. 40, 34132 Kassel, Germany
| | - Tonio Rosen
- Institut für Physik, Universität Kassel, Heinrich-Plett-Str. 40, 34132 Kassel, Germany
| | - Sagnik Das
- Institut für Physik, Universität Kassel, Heinrich-Plett-Str. 40, 34132 Kassel, Germany
| | - Jayanta Ghosh
- Institut für Physik, Universität Kassel, Heinrich-Plett-Str. 40, 34132 Kassel, Germany
| | - Hendrike Braun
- Institut für Physik, Universität Kassel, Heinrich-Plett-Str. 40, 34132 Kassel, Germany
| | - Daniel M. Reich
- Dahlem Center for Complex Quantum Systems and Fachbereich Physik, Freie Universität Berlin, Arnimallee 14, D-14195 Berlin, Germany
| | - Arne Senftleben
- Institut für Physik, Universität Kassel, Heinrich-Plett-Str. 40, 34132 Kassel, Germany
| | - Thomas Baumert
- Institut für Physik, Universität Kassel, Heinrich-Plett-Str. 40, 34132 Kassel, Germany
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13
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Dowek D, Decleva P. Trends in angle-resolved molecular photoelectron spectroscopy. Phys Chem Chem Phys 2022; 24:24614-24654. [DOI: 10.1039/d2cp02725a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
In this perspective article, main trends of angle-resolved molecular photoelectron spectroscopy in the laboratory up to the molecular frame, in different regimes of light-matter interactions, are highlighted with emphasis on foundations and most recent applications.
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Affiliation(s)
- Danielle Dowek
- Université Paris-Saclay, CNRS, Institut des Sciences Moléculaires d’Orsay, 91405 Orsay, France
| | - Piero Decleva
- CNR IOM and Dipartimento DSCF, Università di Trieste, Trieste, Italy
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14
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Marlton SJP, Trevitt A. Laser Photodissocation, Action Spectroscopy and Mass Spectrometry Unite to Detect and Separate Isomers. Chem Commun (Camb) 2022; 58:9451-9467. [DOI: 10.1039/d2cc02101c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The separation and detection of isomers remains a challenge for many areas of mass spectrometry. This article highlights laser photodissociation and ion mobility strategies that have been deployed to tackle...
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15
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Janssen M, Nahon L, Smirnova O, Stolow A. Fundamentals and applications of molecular photoelectron spectroscopy – Festschrift for Ivan Powis. Phys Chem Chem Phys 2022; 24:24611-24613. [DOI: 10.1039/d2cp90168d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
This themed collection includes a collection of articles on fundamentals and applications of molecular photoelectron spectroscopy.
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Affiliation(s)
| | | | - Olga Smirnova
- Max Born Institute and Technical University Berlin, Germany
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16
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Singh DP, Thompson JOF, Reid KL, Powis I. Influence of Vibrational Excitation and Nuclear Dynamics in Multiphoton Photoelectron Circular Dichroism of Fenchone. J Phys Chem Lett 2021; 12:11438-11443. [PMID: 34792356 DOI: 10.1021/acs.jpclett.1c03231] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
We report photoelectron circular dichroism of S-(+)-fenchone enantiomers recorded with state-state vibrational level resolution using picosecond laser (2 + 1) resonance enhanced multiphoton ionization via 3s and 3p Rydberg intermediate states. The 3p state decays to the 3s state on a picosecond time scale so that, above the 3p Rydberg excitation threshold, ionization of vibrationally hot 3s states competes with direct 3p-1 ionization. Complex vibronic dynamics of the 3p → 3s internal conversion weaken the Rydberg Δv = 0 propensity rule in both the 3p-1 and 3s-1 ionization channels. Large variations of the forward-backward chiral asymmetry factors are observed between the Δv = 0 and Δv > 0 vibrational transitions, including dramatic swings from up to ±17%. Such changes of sign indicate complete reversal of the preferred direction for photoelectron emission in the laboratory frame, associated with vibrational motion. These asymmetry switches easily exceed the amplitude and frequency of such vibrationally induced flips previously observed in single photon ionization.
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Affiliation(s)
- Dhirendra P Singh
- School of Chemistry, The University of Nottingham, University Park, Nottingham NG7 2RD, U.K
| | - James O F Thompson
- School of Chemistry, The University of Nottingham, University Park, Nottingham NG7 2RD, U.K
| | - Katharine L Reid
- School of Chemistry, The University of Nottingham, University Park, Nottingham NG7 2RD, U.K
| | - Ivan Powis
- School of Chemistry, The University of Nottingham, University Park, Nottingham NG7 2RD, U.K
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17
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Yoo IT, Eun HJ, Min A, Jeon CW, Jeong J, Heo J, Kim NJ. Ultraviolet photodissociation circular dichroism spectroscopy of protonated L-phenylalanyl-L-alanine in a cryogenic ion trap. Phys Chem Chem Phys 2021; 23:24180-24186. [PMID: 34676382 DOI: 10.1039/d1cp04030h] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
We obtained ultraviolet photodissociation (UVPD) circular dichroism (CD) spectra of protonated L-phenylalanyl-L-alanine (L-H+PheAla) near the origin band of the S0-S1 transition using cryogenic ion spectroscopy. Infrared (IR) ion-dip, IR-UV hole burning (HB) and UV-UV HB spectra showed that L-H+PheAla existed as two different conformers in a cryogenic ion trap, and they had nearly identical peptide backbones but different conformations in the Phe side chain. The UVPD CD spectra revealed that the two conformers had opposite CD signs and significantly different CD magnitudes from each other. These results demonstrate that the CD value of L-H+PheAla near the origin band is strongly influenced by the conformation of the Phe side chain.
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Affiliation(s)
- Il Tae Yoo
- Department of Chemistry, Chungbuk National University, Chungbuk 28644, Korea.
| | - Han Jun Eun
- Department of Chemistry, Chungbuk National University, Chungbuk 28644, Korea.
| | - Ahreum Min
- Department of Chemistry (BK21 +) and Research Institute of Natural Science, Gyeongsang National University, Jinju 52828, Korea
| | - Chang Wook Jeon
- Department of Chemistry, Chungbuk National University, Chungbuk 28644, Korea.
| | - Jinho Jeong
- Department of Chemistry, Chungbuk National University, Chungbuk 28644, Korea.
| | - Jiyoung Heo
- Department of Green Chemical Engineering, Sangmyung University, Chungnam 31066, Korea
| | - Nam Joon Kim
- Department of Chemistry, Chungbuk National University, Chungbuk 28644, Korea.
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Krüger P, Weitzel K. Photoelectron Circular Dichroism in the Photodetachment of Amino Acid Anions. Angew Chem Int Ed Engl 2021; 60:17861-17865. [PMID: 34137142 PMCID: PMC8457165 DOI: 10.1002/anie.202107150] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2021] [Indexed: 01/31/2023]
Abstract
The chirality of chemical compounds is of undisputed importance in science and technology. In particular with respect to pharmacological application most molecules of interest cannot be accessed by the powerful techniques developed in recent years for gas phase analytes. Here, we demonstrate that the combination of electrospray ionization (ESI) with the detection of photoelectron circular dichroism (PECD) provides access to chirality information applicable to molecular materials with negligible vapor pressure, for example, amino acids. To this end, glutamic acid and 3,4-dihydroxyphenylalanine (DOPA) have been electrosprayed into the source of a chirality spectrometer, where photodetachment is enforced and the PECD is detected. The technique can be expected to be conceptually applicable to all chemical systems with chirality based on molecular properties.
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Affiliation(s)
- Peter Krüger
- Fachbereich ChemiePhilipps-Universität Marburg35032MarburgGermany
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