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Makhija V, Gupta R, Neville S, Schuurman M, Francisco J, Kais S. Time Resolved Quantum Tomography in Molecular Spectroscopy by the Maximal Entropy Approach. J Phys Chem Lett 2024; 15:9525-9534. [PMID: 39264357 DOI: 10.1021/acs.jpclett.4c02368] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/13/2024]
Abstract
Attosecond science offers unprecedented precision in probing the initial moments of chemical reactions, revealing the dynamics of molecular electrons that shape reaction pathways. A fundamental question emerges: what role, if any, do quantum coherences between molecular electron states play in photochemical reactions? Answering this question necessitates quantum tomography─the determination of the electronic density matrix from experimental data, where the off-diagonal elements represent these coherences. The Maximal Entropy (MaxEnt) based Quantum State Tomography (QST) approach offers unique advantages in studying molecular dynamics, particularly with partial tomographic data. Here, we explore the application of MaxEnt-based QST on photoexcited ammonia, necessitating the operator form of observables specific to the performed measurements. We present two methodologies for constructing these operators: one leveraging Molecular Angular Distribution Moments (MADMs) which accurately capture the orientation-dependent vibronic dynamics of molecules and another utilizing Angular Momentum Coherence Operators to construct measurement operators for the full rovibronic density matrix in the symmetric top basis. A key revelation of our study is the direct link between Lagrange multipliers in the MaxEnt formalism and the unique set of MADMs. Additionally, we visualize the electron density within the molecular frame, demonstrating charge migration across the molecule. Furthermore, we achieve a groundbreaking milestone by constructing, for the first time, the entanglement entropy of the electronic subsystem─a metric that was previously inaccessible. The entropy vividly reveals and quantifies the effects of coupling between the excited electron and nuclear degrees of freedom. Consequently, our findings open new avenues for research in ultrafast molecular spectroscopy within the broader domain of quantum information science, offering profound implications for the study of molecular systems under excitation using quantum tomographic schemes.
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Affiliation(s)
- Varun Makhija
- Department of Chemistry and Physics, University of Mary Washington, Fredericksburg, Virginia 22401, United States
| | - Rishabh Gupta
- Department of Chemistry, Purdue University, West Lafayette, Indiana 47907, United States
| | - Simon Neville
- National Research Council Canada, 100 Sussex Drive, Ottawa, Ontario K1A 0R6, Canada
| | - Michael Schuurman
- National Research Council Canada, 100 Sussex Drive, Ottawa, Ontario K1A 0R6, Canada
- Department of Chemistry, University of Ottawa, Ottawa, Ontario K1N 6N5, Canada
| | - Joseph Francisco
- Department of Earth and Environmental Science and Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
| | - Sabre Kais
- Department of Electrical and Computer Engineering, North Carolina State University, Raleigh, North Carolina 27606, United States
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2
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Morrigan L, Neville SP, Gregory M, Boguslavskiy AE, Forbes R, Wilkinson I, Lausten R, Stolow A, Schuurman MS, Hockett P, Makhija V. Ultrafast Molecular Frame Quantum Tomography. PHYSICAL REVIEW LETTERS 2023; 131:193001. [PMID: 38000424 DOI: 10.1103/physrevlett.131.193001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/15/2023] [Revised: 09/05/2023] [Accepted: 10/03/2023] [Indexed: 11/26/2023]
Abstract
We develop and experimentally demonstrate a methodology for a full molecular frame quantum tomography (MFQT) of dynamical polyatomic systems. We exemplify this approach through the complete characterization of an electronically nonadiabatic wave packet in ammonia (NH_{3}). The method exploits both energy and time-domain spectroscopic data, and yields the lab frame density matrix (LFDM) for the system, the elements of which are populations and coherences. The LFDM fully characterizes electronic and nuclear dynamics in the molecular frame, yielding the time- and orientation-angle dependent expectation values of any relevant operator. For example, the time-dependent molecular frame electronic probability density may be constructed, yielding information on electronic dynamics in the molecular frame. In NH_{3}, we observe that electronic coherences are induced by nuclear dynamics which nonadiabatically drive electronic motions (charge migration) in the molecular frame. Here, the nuclear dynamics are rotational and it is nonadiabatic Coriolis coupling which drives the coherences. Interestingly, the nuclear-driven electronic coherence is preserved over longer timescales. In general, MFQT can help quantify entanglement between electronic and nuclear degrees of freedom, and provide new routes to the study of ultrafast molecular dynamics, charge migration, quantum information processing, and optimal control schemes.
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Affiliation(s)
- Luna Morrigan
- Department of Chemistry and Physics, University of Mary Washington, Fredericksburg, Virginia 22401, USA
| | - Simon P Neville
- National Research Council Canada, 100 Sussex Drive, Ottawa, Ontario K1A 0R6, Canada
| | - Margaret Gregory
- Department of Chemistry and Physics, University of Mary Washington, Fredericksburg, Virginia 22401, USA
| | - Andrey E Boguslavskiy
- Department of Physics, University of Ottawa, 150 Louis Pasteur, Ottawa, Ontario K1N 6N5, Canada
- Department of Chemistry and Biomolecular Sciences, University of Ottawa, Ottawa, Ontario K1N 6N5, Canada
| | - Ruaridh Forbes
- Department of Physics, University of Ottawa, 150 Louis Pasteur, Ottawa, Ontario K1N 6N5, Canada
- Linac Coherent Light Source, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
| | - Iain Wilkinson
- National Research Council Canada, 100 Sussex Drive, Ottawa, Ontario K1A 0R6, Canada
- Institute for Electronic Structure Dynamics, Helmholtz-Zentrum für Materialien und Energie, Hahn-Meitner-Platz 1, 14109 Berlin, Germany
| | - Rune Lausten
- National Research Council Canada, 100 Sussex Drive, Ottawa, Ontario K1A 0R6, Canada
| | - Albert Stolow
- National Research Council Canada, 100 Sussex Drive, Ottawa, Ontario K1A 0R6, Canada
- Department of Physics, University of Ottawa, 150 Louis Pasteur, Ottawa, Ontario K1N 6N5, Canada
- Department of Chemistry and Biomolecular Sciences, University of Ottawa, Ottawa, Ontario K1N 6N5, Canada
- NRC-uOttawa Joint Centre for Extreme and Quantum Photonics (JCEP), Ottawa, Ontario K1A 0R6, Canada
| | - Michael S Schuurman
- National Research Council Canada, 100 Sussex Drive, Ottawa, Ontario K1A 0R6, Canada
- Department of Chemistry and Biomolecular Sciences, University of Ottawa, Ottawa, Ontario K1N 6N5, Canada
| | - Paul Hockett
- National Research Council Canada, 100 Sussex Drive, Ottawa, Ontario K1A 0R6, Canada
| | - Varun Makhija
- Department of Chemistry and Physics, University of Mary Washington, Fredericksburg, Virginia 22401, USA
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Schwickert D, Ruberti M, Kolorenč P, Przystawik A, Skruszewicz S, Sumfleth M, Braune M, Bocklage L, Carretero L, Czwalinna MK, Diaman D, Düsterer S, Kuhlmann M, Palutke S, Röhlsberger R, Rönsch-Schulenburg J, Toleikis S, Usenko S, Viefhaus J, Vorobiov A, Martins M, Kip D, Averbukh V, Marangos JP, Laarmann T. Charge-induced chemical dynamics in glycine probed with time-resolved Auger electron spectroscopy. STRUCTURAL DYNAMICS (MELVILLE, N.Y.) 2022; 9:064301. [PMID: 36389279 PMCID: PMC9646253 DOI: 10.1063/4.0000165] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/28/2022] [Accepted: 10/17/2022] [Indexed: 06/16/2023]
Abstract
In the present contribution, we use x-rays to monitor charge-induced chemical dynamics in the photoionized amino acid glycine with femtosecond time resolution. The outgoing photoelectron leaves behind the cation in a coherent superposition of quantum mechanical eigenstates. Delayed x-ray pulses track the induced coherence through resonant x-ray absorption that induces Auger decay. Temporal modulation of the Auger electron signal correlated with specific ions is observed, which is governed by the initial electronic coherence and subsequent vibronic coupling to nuclear degrees of freedom. In the time-resolved x-ray absorption measurement, we monitor the time-frequency spectra of the resulting many-body quantum wave packets for a period of 175 fs along different reaction coordinates. Our experiment proves that by measuring specific fragments associated with the glycine dication as a function of the pump-probe delay, one can selectively probe electronic coherences at early times associated with a few distinguishable components of the broad electronic wave packet created initially by the pump pulse in the cation. The corresponding coherent superpositions formed by subsets of electronic eigenstates and evolving along parallel dynamical pathways show different phases and time periods in the range of ( - 0.3 ± 0.1 ) π ≤ ϕ ≤ ( 0.1 ± 0.2 ) π and 18.2 - 1.4 + 1.7 ≤ T ≤ 23.9 - 1.1 + 1.2 fs. Furthermore, for long delays, the data allow us to pinpoint the driving vibrational modes of chemical dynamics mediating charge-induced bond cleavage along different reaction coordinates.
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Affiliation(s)
- David Schwickert
- Deutsches Elektronen-Synchrotron DESY, Notkestr. 85, 22607 Hamburg, Germany
| | - Marco Ruberti
- Department of Physics, Imperial College London, Prince Consort Road, London SW7 2AZ, United Kingdom
| | - Přemysl Kolorenč
- Charles University, Faculty of Mathematics and Physics, V Holesovickach 2, 180 00 Praha 8, Czech Republic
| | - Andreas Przystawik
- Deutsches Elektronen-Synchrotron DESY, Notkestr. 85, 22607 Hamburg, Germany
| | | | - Malte Sumfleth
- Deutsches Elektronen-Synchrotron DESY, Notkestr. 85, 22607 Hamburg, Germany
| | - Markus Braune
- Deutsches Elektronen-Synchrotron DESY, Notkestr. 85, 22607 Hamburg, Germany
| | | | - Luis Carretero
- Deutsches Elektronen-Synchrotron DESY, Notkestr. 85, 22607 Hamburg, Germany
| | | | - Dian Diaman
- Deutsches Elektronen-Synchrotron DESY, Notkestr. 85, 22607 Hamburg, Germany
| | - Stefan Düsterer
- Deutsches Elektronen-Synchrotron DESY, Notkestr. 85, 22607 Hamburg, Germany
| | - Marion Kuhlmann
- Deutsches Elektronen-Synchrotron DESY, Notkestr. 85, 22607 Hamburg, Germany
| | - Steffen Palutke
- Deutsches Elektronen-Synchrotron DESY, Notkestr. 85, 22607 Hamburg, Germany
| | | | | | - Sven Toleikis
- Deutsches Elektronen-Synchrotron DESY, Notkestr. 85, 22607 Hamburg, Germany
| | - Sergey Usenko
- European XFEL GmbH, Holzkoppel 4, 22869 Schenefeld, Germany
| | - Jens Viefhaus
- Helmholtz-Zentrum Berlin für Materialien und Energie, Albert-Einstein-Straße 15, 12489 Berlin, Germany
| | - Anton Vorobiov
- Faculty of Electrical Engineering, Helmut Schmidt University, Holstenhofweg 85, 22043 Hamburg, Germany
| | - Michael Martins
- Department of Physics, University of Hamburg, Luruper Chaussee 149, 22761 Hamburg, Germany
| | - Detlef Kip
- Faculty of Electrical Engineering, Helmut Schmidt University, Holstenhofweg 85, 22043 Hamburg, Germany
| | - Vitali Averbukh
- Department of Physics, Imperial College London, Prince Consort Road, London SW7 2AZ, United Kingdom
| | - Jon P. Marangos
- Department of Physics, Imperial College London, Prince Consort Road, London SW7 2AZ, United Kingdom
| | - Tim Laarmann
- Author to whom correspondence should be addressed:
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Gregory M, Neville S, Schuurman M, Makhija V. A laboratory frame density matrix for ultrafast quantum molecular dynamics. J Chem Phys 2022; 157:164301. [DOI: 10.1063/5.0109607] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
In most cases, the ultrafast dynamics of resonantly excited molecules are considered and almost always computed in the molecular frame, while experiments are carried out in the laboratory frame. Here, we provide a formalism in terms of a lab frame density matrix, which connects quantum dynamics in the molecular frame to those in the laboratory frame, providing a transparent link between computation and measurement. The formalism reveals that in any such experiment, the molecular frame dynamics vary for molecules in different orientations and that certain coherences, which are potentially experimentally accessible, are rejected by the orientation-averaged reduced vibronic density matrix. Instead, molecular angular distribution moments are introduced as a more accurate representation of experimentally accessible information. Furthermore, the formalism provides a clear definition of a molecular frame quantum tomography and specifies the requirements to perform such a measurement enabling the experimental imaging of molecular frame vibronic dynamics. Successful completion of such a measurement fully characterizes the molecular frame quantum dynamics for a molecule at any orientation in the laboratory frame.
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Affiliation(s)
- Margaret Gregory
- Department of Chemistry and Physics, University of Mary Washington, 1301 College Avenue, Fredericksburg, Virginia 22401, USA
| | - Simon Neville
- National Research Council Canada, 100 Sussex Drive, Ottawa, Ontario K1A 0R6, Canada
| | - Michael Schuurman
- National Research Council Canada, 100 Sussex Drive, Ottawa, Ontario K1A 0R6, Canada
- Department of Chemistry and Biomolecular Sciences, University of Ottawa, 150 Louis Pasteur, Ottawa, Ontario K1N 6N5, Canada
| | - Varun Makhija
- Department of Chemistry and Physics, University of Mary Washington, 1301 College Avenue, Fredericksburg, Virginia 22401, USA
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Ruberti M, Patchkovskii S, Averbukh V. Quantum coherence in molecular photoionization. Phys Chem Chem Phys 2022; 24:19673-19686. [PMID: 35946491 DOI: 10.1039/d2cp01562e] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The study of onset and decay, as well as control of ultrafast quantum coherence in many-electron systems is in the focus of interest of attosecond physics. Interpretation of attosecond experiments detecting the ultrafast quantum coherence requires application of advanced theoretical and computational tools combining many-electron theory, description of the electronic continuum, including in the strong laser field scenario, as well as nuclear dynamics theory. This perspective reviews the recent theoretical advances in understanding the attosecond dynamics of quantum coherence in photoionized molecular systems and outlines possible future directions of theoretical and experimental study of coherence and entanglement in the attosecond regime.
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Affiliation(s)
- Marco Ruberti
- Imperial College London, Department of Physics, South Kensington Campus, London SW7 2AZ, UK.
| | | | - Vitali Averbukh
- Imperial College London, Department of Physics, South Kensington Campus, London SW7 2AZ, UK.
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6
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Maxwell AS, Madsen LB, Lewenstein M. Entanglement of orbital angular momentum in non-sequential double ionization. Nat Commun 2022; 13:4706. [PMID: 35948552 PMCID: PMC9365801 DOI: 10.1038/s41467-022-32128-z] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2022] [Accepted: 07/19/2022] [Indexed: 11/30/2022] Open
Abstract
Entanglement has a capacity to enhance imaging procedures, but this remains unexplored for attosecond imaging. Here, we elucidate that possibility, addressing orbital angular momentum (OAM) entanglement in ultrafast processes. In the correlated process non-sequential double ionization (NSDI) we demonstrate robust photoelectron entanglement. In contrast to commonly considered continuous variables, the discrete OAM allows for a simpler interpretation, computation, and measurement of entanglement. The logarithmic negativity reveals that the entanglement is robust to incoherence and an entanglement witness minimizes the number of measurements to detect the entanglement, both quantities are related to OAM coherence terms. We quantify the entanglement for a range of targets and field parameters to find the most entangled photoelectron pairs. This methodology provides a general way to use OAM to quantify and measure entanglement, well-suited to attosecond processes, and can be exploited to enhance imaging capabilities through correlated measurements, or for generation of OAM-entangled electrons.
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Affiliation(s)
- Andrew S Maxwell
- ICFO-Institut de Ciencies Fotoniques, The Barcelona Institute of Science and Technology, Av. Carl Friedrich Gauss 3, 08860, Castelldefels, Barcelona, Spain.
- Department of Physics and Astronomy, Aarhus University, DK-8000, Aarhus C, Denmark.
| | - Lars Bojer Madsen
- Department of Physics and Astronomy, Aarhus University, DK-8000, Aarhus C, Denmark
| | - Maciej Lewenstein
- ICFO-Institut de Ciencies Fotoniques, The Barcelona Institute of Science and Technology, Av. Carl Friedrich Gauss 3, 08860, Castelldefels, Barcelona, Spain
- ICREA, Pg. Lluís Companys 23, 08010, Barcelona, Spain
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7
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Schwickert D, Ruberti M, Kolorenč P, Usenko S, Przystawik A, Baev K, Baev I, Braune M, Bocklage L, Czwalinna MK, Deinert S, Düsterer S, Hans A, Hartmann G, Haunhorst C, Kuhlmann M, Palutke S, Röhlsberger R, Rönsch-Schulenburg J, Schmidt P, Toleikis S, Viefhaus J, Martins M, Knie A, Kip D, Averbukh V, Marangos JP, Laarmann T. Electronic quantum coherence in glycine molecules probed with ultrashort x-ray pulses in real time. SCIENCE ADVANCES 2022; 8:eabn6848. [PMID: 35648864 PMCID: PMC9159702 DOI: 10.1126/sciadv.abn6848] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/13/2021] [Accepted: 04/15/2022] [Indexed: 06/15/2023]
Abstract
Here, we use x-rays to create and probe quantum coherence in the photoionized amino acid glycine. The outgoing photoelectron leaves behind the cation in a coherent superposition of quantum mechanical eigenstates. Delayed x-ray pulses track the induced coherence through resonant x-ray absorption that induces Auger decay and by photoelectron emission from sequential double photoionization. Sinusoidal temporal modulation of the detected signal at early times (0 to 25 fs) is observed in both measurements. Advanced ab initio many-electron simulations allow us to explain the first 25 fs of the detected coherent quantum evolution in terms of the electronic coherence. In the kinematically complete x-ray absorption measurement, we monitor its dynamics for a period of 175 fs and observe an evolving modulation that may implicate the coupling of electronic to vibronic coherence at longer time scales. Our experiment provides a direct support for the existence of long-lived electronic coherence in photoionized biomolecules.
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Affiliation(s)
- David Schwickert
- Deutsches Elektronen-Synchrotron DESY, Notkestr. 85, 22607 Hamburg, Germany
| | - Marco Ruberti
- Department of Physics, Imperial College London, Prince Consort Road, London SW7 2AZ, UK
| | - Přemysl Kolorenč
- Faculty of Mathematics and Physics, Charles University, V Holesovickach 2, 180 00 Praha 8, Czech Republic
| | - Sergey Usenko
- Deutsches Elektronen-Synchrotron DESY, Notkestr. 85, 22607 Hamburg, Germany
- Department of Physics, University of Hamburg, Luruper Chaussee 149, 22761 Hamburg, Germany
| | - Andreas Przystawik
- Deutsches Elektronen-Synchrotron DESY, Notkestr. 85, 22607 Hamburg, Germany
| | - Karolin Baev
- Deutsches Elektronen-Synchrotron DESY, Notkestr. 85, 22607 Hamburg, Germany
- Department of Physics, University of Hamburg, Luruper Chaussee 149, 22761 Hamburg, Germany
| | - Ivan Baev
- Department of Physics, University of Hamburg, Luruper Chaussee 149, 22761 Hamburg, Germany
| | - Markus Braune
- Deutsches Elektronen-Synchrotron DESY, Notkestr. 85, 22607 Hamburg, Germany
| | - Lars Bocklage
- Deutsches Elektronen-Synchrotron DESY, Notkestr. 85, 22607 Hamburg, Germany
- The Hamburg Centre for Ultrafast Imaging CUI, Luruper Chaussee 149, 22761 Hamburg, Germany
| | | | - Sascha Deinert
- Deutsches Elektronen-Synchrotron DESY, Notkestr. 85, 22607 Hamburg, Germany
| | - Stefan Düsterer
- Deutsches Elektronen-Synchrotron DESY, Notkestr. 85, 22607 Hamburg, Germany
| | - Andreas Hans
- Institute of Physics, University of Kassel, Heinrich-Plett-Str. 40, 34132 Kassel, Germany
| | - Gregor Hartmann
- Institute of Physics, University of Kassel, Heinrich-Plett-Str. 40, 34132 Kassel, Germany
| | - Christian Haunhorst
- Faculty of Electrical Engineering, Helmut Schmidt University, Holstenhofweg 85, 22043 Hamburg, Germany
- Helmholtz Institute Jena, Fröbelstieg 3, 07743 Jena, Germany
| | - Marion Kuhlmann
- Deutsches Elektronen-Synchrotron DESY, Notkestr. 85, 22607 Hamburg, Germany
| | - Steffen Palutke
- Deutsches Elektronen-Synchrotron DESY, Notkestr. 85, 22607 Hamburg, Germany
| | - Ralf Röhlsberger
- Deutsches Elektronen-Synchrotron DESY, Notkestr. 85, 22607 Hamburg, Germany
- Helmholtz Institute Jena, Fröbelstieg 3, 07743 Jena, Germany
- Helmholtz Centre for Heavy Ion Research (GSI), Planckstr. 1, 64291 Darmstadt, Germany
- Friedrich-Schiller-Universität Jena, Max-Wien-Platz 1, 07743 Jena, Germany
| | | | - Philipp Schmidt
- Institute of Physics, University of Kassel, Heinrich-Plett-Str. 40, 34132 Kassel, Germany
| | - Sven Toleikis
- Deutsches Elektronen-Synchrotron DESY, Notkestr. 85, 22607 Hamburg, Germany
| | - Jens Viefhaus
- Helmholtz-Zentrum Berlin für Materialien und Energie, Albert-Einstein-Straße 15, 12489 Berlin, Germany
| | - Michael Martins
- Department of Physics, University of Hamburg, Luruper Chaussee 149, 22761 Hamburg, Germany
| | - André Knie
- Institute of Physics, University of Kassel, Heinrich-Plett-Str. 40, 34132 Kassel, Germany
| | - Detlef Kip
- Faculty of Electrical Engineering, Helmut Schmidt University, Holstenhofweg 85, 22043 Hamburg, Germany
| | - Vitali Averbukh
- Department of Physics, Imperial College London, Prince Consort Road, London SW7 2AZ, UK
| | - Jon P. Marangos
- Department of Physics, Imperial College London, Prince Consort Road, London SW7 2AZ, UK
| | - Tim Laarmann
- Deutsches Elektronen-Synchrotron DESY, Notkestr. 85, 22607 Hamburg, Germany
- The Hamburg Centre for Ultrafast Imaging CUI, Luruper Chaussee 149, 22761 Hamburg, Germany
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Yang M, Sissay A, Chen M, Lopata K. Intruder Peak-Free Transient Inner-Shell Spectra Using Real-Time Simulations. J Chem Theory Comput 2022; 18:992-1002. [PMID: 35025498 DOI: 10.1021/acs.jctc.1c00079] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Real-time methods are convenient for simulating core-level absorption spectra but suffer from nonphysical intruder peaks when using atom-centered basis sets. In transient absorption spectra, these peaks exhibit highly nonphysical time-dependent modulations in their energies and oscillator strengths. In this paper, we address the origins of these intruder peaks and propose a straightforward and effective solution based on a filtered dipole operator. In combination with real-time time-dependent density functional theory (RT-TDDFT), we demonstrate how to compute intruder-free attosecond transient X-ray absorption spectra for the aminophenol (C6H7NO) oxygen and nitrogen K-edges and the α-quartz (SiO2) silicon L-edge. Without filtering, the computed spectra are qualitatively wrong. This procedure is suitable for both static and transient inner-shell spectroscopy studies and can easily be implemented in a range of real-time methodologies.
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Affiliation(s)
- Mengqi Yang
- Department of Chemistry, Louisiana State University, Baton Rouge, Louisiana 70803, United States
| | - Adonay Sissay
- Department of Chemistry, Louisiana State University, Baton Rouge, Louisiana 70803, United States
| | - Min Chen
- Department of Chemistry, Louisiana State University, Baton Rouge, Louisiana 70803, United States
| | - Kenneth Lopata
- Department of Chemistry, Louisiana State University, Baton Rouge, Louisiana 70803, United States.,Center for Computation and Technology, Louisiana State University, Baton Rouge, Louisiana 70803, United States
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