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Sparling C, Ruget A, Ireland L, Kotsina N, Ghafur O, Leach J, Townsend D. The importance of molecular axis alignment and symmetry-breaking in photoelectron elliptical dichroism. J Chem Phys 2023; 159:214301. [PMID: 38038198 DOI: 10.1063/5.0180361] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2023] [Accepted: 11/06/2023] [Indexed: 12/02/2023] Open
Abstract
Photoelectron angular distributions (PADs) produced from the photoionization of chiral molecules using elliptically polarized light exhibit a forward/backward asymmetry with respect to the optical propagation direction. By recording these distributions using the velocity-map imaging (VMI) technique, the resulting photoelectron elliptical dichroism (PEELD) has previously been demonstrated as a promising spectroscopic tool for studying chiral molecules in the gas phase. The use of elliptically polarized laser pulses, however, produces PADs (and consequently, PEELD distributions) that do not exhibit cylindrical symmetry about the propagation axis. This leads to significant limitations and challenges when employing conventional VMI acquisition and data processing strategies. Using novel photoelectron image analysis methods based around Hankel transform reconstruction tomography and machine learning, however, we have quantified-for the first time-significant symmetry-breaking contributions to PEELD signals that are of a comparable magnitude to the symmetric terms in the multiphoton ionization of (1R,4R)-(+)- and (1S,4S)-(-)-camphor. This contradicts any assumptions that symmetry-breaking can be ignored when reconstructing VMI data. Furthermore, these same symmetry-breaking terms are expected to appear in any experiment where circular and linear laser fields are used together. This ionization scheme is particularly relevant for investigating dynamics in chiral molecules, but it is not limited to them. Developing a full understanding of these terms and the role they play in the photoionization of chiral molecules is of clear importance if the potential of PEELD and related effects for future practical applications is to be fully realized.
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Affiliation(s)
- Chris Sparling
- Institute of Photonics & Quantum Sciences, Heriot-Watt University, Edinburgh EH14 4AS, United Kingdom
| | - Alice Ruget
- Institute of Photonics & Quantum Sciences, Heriot-Watt University, Edinburgh EH14 4AS, United Kingdom
| | - Lewis Ireland
- Institute of Photonics & Quantum Sciences, Heriot-Watt University, Edinburgh EH14 4AS, United Kingdom
| | - Nikoleta Kotsina
- Institute of Photonics & Quantum Sciences, Heriot-Watt University, Edinburgh EH14 4AS, United Kingdom
| | - Omair Ghafur
- Institute of Photonics & Quantum Sciences, Heriot-Watt University, Edinburgh EH14 4AS, United Kingdom
| | - Jonathan Leach
- Institute of Photonics & Quantum Sciences, Heriot-Watt University, Edinburgh EH14 4AS, United Kingdom
| | - Dave Townsend
- Institute of Photonics & Quantum Sciences, Heriot-Watt University, Edinburgh EH14 4AS, United Kingdom
- Institute of Chemical Sciences, Heriot-Watt University, Edinburgh EH14 4AS, United Kingdom
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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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Arlt J, Singh DP, Thompson JOF, Chatterley AS, Hockett P, Stapelfeldt H, Reid KL. Photoelectron angular distributions from resonant two-photon ionisation of adiabatically aligned naphthalene and aniline molecules. Mol Phys 2020. [DOI: 10.1080/00268976.2020.1836411] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Affiliation(s)
- Jacqueline Arlt
- Department of Chemistry, Aarhus University, Aarhus C, Denmark
| | | | | | | | - Paul Hockett
- Steacie Institute for Molecular Science, National Research Council of Canada, Ottawa, Canada
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Thesing LV, Yachmenev A, González-Férez R, Küpper J. The Effect of Nuclear-Quadrupole Coupling in the Laser-Induced Alignment of Molecules. J Phys Chem A 2020; 124:2225-2230. [PMID: 32077290 DOI: 10.1021/acs.jpca.9b11433] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We present a theoretical study of the time-dependent laser alignment of molecules taking into account the hyperfine coupling due to nuclear-quadrupole interactions. The coupling of nuclear spins to the overall angular momentum of molecules significantly influences their rotational dynamics. Here, we systematically analyze the impact of the nuclear-quadrupole coupling on the rotational dynamics of the linear and the asymmetric-top diiodobenzene molecule induced by external laser fields. We explore different regimes of pulse shapes and laser-pulse intensities and detail under which conditions the quadrupole coupling cannot be neglected in the description of the laser alignment of molecules.
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Affiliation(s)
- Linda V Thesing
- Center for Free-Electron Laser Science, Deutsches Elektronen-Synchrotron DESY, Notkestrasse 85, 22607 Hamburg, Germany.,Center for Ultrafast Imaging, Universität Hamburg, Luruper Chaussee 149, 22761 Hamburg, Germany.,Department of Physics, Universität Hamburg, Luruper Chaussee 149, Hamburg 22761, Germany
| | - Andrey Yachmenev
- Center for Free-Electron Laser Science, Deutsches Elektronen-Synchrotron DESY, Notkestrasse 85, 22607 Hamburg, Germany.,Center for Ultrafast Imaging, Universität Hamburg, Luruper Chaussee 149, 22761 Hamburg, Germany
| | - Rosario González-Férez
- Instituto Carlos I de Fı́sica Teórica y Computacional and Departamento de Fı́sica Atómica, Molecular y Nuclear, Universidad de Granada, 18071 Granada, Spain
| | - Jochen Küpper
- Center for Free-Electron Laser Science, Deutsches Elektronen-Synchrotron DESY, Notkestrasse 85, 22607 Hamburg, Germany.,Center for Ultrafast Imaging, Universität Hamburg, Luruper Chaussee 149, 22761 Hamburg, Germany.,Department of Physics, Universität Hamburg, Luruper Chaussee 149, Hamburg 22761, Germany.,Department of Chemistry, Universität Hamburg, Luruper Chaussee 149, Hamburg 22761, Germany
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Long-lasting field-free alignment of large molecules inside helium nanodroplets. Nat Commun 2019; 10:133. [PMID: 30635554 PMCID: PMC6329814 DOI: 10.1038/s41467-018-07995-0] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2018] [Accepted: 12/05/2018] [Indexed: 11/09/2022] Open
Abstract
Molecules with their axes sharply confined in space, available through laser-induced alignment methods, are essential for many current experiments, including ultrafast molecular imaging. For these applications the aligning laser field should ideally be turned-off, to avoid undesired perturbations, and the strong alignment should last long enough that reactions and dynamics can be mapped out. Presently, this is only possible for small, linear molecules and for times less than 1 picosecond. Here, we demonstrate strong, field-free alignment of large molecules inside helium nanodroplets, lasting >10 picoseconds. One-dimensional or three-dimensional alignment is created by a slowly switched-on laser pulse, made field-free through rapid pulse truncation, and retained thanks to the impeding effect of the helium environment on molecular rotation. The opportunities field-free aligned molecules open are illustrated by measuring the alignment-dependent strong-field ionization yield of dibromothiophene oligomers. Our technique will enable molecular frame experiments, including ultrafast excited state dynamics, on a variety of large molecules and complexes.
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Stace AJ, Clary DC. Modern theoretical chemistry: the legacy of Prof. John N. Murrell. PHILOSOPHICAL TRANSACTIONS. SERIES A, MATHEMATICAL, PHYSICAL, AND ENGINEERING SCIENCES 2018; 376:rsta.2017.0460. [PMID: 29431685 PMCID: PMC5805920 DOI: 10.1098/rsta.2017.0460] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 12/13/2017] [Indexed: 06/08/2023]
Affiliation(s)
- Anthony J Stace
- School of Chemistry, University of Nottingham, University Park, Nottingham NG7 2RD, UK
| | - David C Clary
- Department of Physical and Theoretical Chemistry, University of Oxford, South Parks Road, Oxford OX1 3QZ, UK
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