1
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Gaba NP, de Moura CEV, Majumder R, Sokolov AY. Simulating transient X-ray photoelectron spectra of Fe(CO) 5 and its photodissociation products with multireference algebraic diagrammatic construction theory. Phys Chem Chem Phys 2024; 26:15927-15938. [PMID: 38805029 DOI: 10.1039/d4cp00801d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/29/2024]
Abstract
Accurate simulations of transient X-ray photoelectron spectra (XPS) provide unique opportunities to bridge the gap between theory and experiment in understanding the photoactivated dynamics in molecules and materials. However, simulating X-ray photoelectron spectra along a photochemical reaction pathway is challenging as it requires accurate description of electronic structure incorporating core-hole screening, orbital relaxation, electron correlation, and spin-orbit coupling in excited states or at nonequilibrium ground-state geometries. In this work, we employ the recently developed multireference algebraic diagrammatic construction theory (MR-ADC) to investigate the core-ionized states and X-ray photoelectron spectra of Fe(CO)5 and its photodissociation products (Fe(CO)4, Fe(CO)3) following excitation with 266 nm light. The simulated transient Fe 3p and CO 3σ XPS spectra incorporating spin-orbit coupling and high-order electron correlation effects are shown to be in a good agreement with the experimental measurements by Leitner et al. [J. Chem. Phys., 2018, 149, 044307]. Our calculations suggest that core-hole screening, spin-orbit coupling, and ligand-field splitting effects are similarly important in reproducing the experimentally observed chemical shifts in transient Fe 3p XPS spectra of iron carbonyl complexes. Our results also demonstrate that the MR-ADC methods can be very useful in interpreting the transient XPS spectra of transition metal compounds.
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Affiliation(s)
- Nicholas P Gaba
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, Ohio, 43210, USA.
| | - Carlos E V de Moura
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, Ohio, 43210, USA.
| | - Rajat Majumder
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, Ohio, 43210, USA.
| | - Alexander Yu Sokolov
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, Ohio, 43210, USA.
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2
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Leone SR. Reinvented: An Attosecond Chemist. Annu Rev Phys Chem 2024; 75:1-19. [PMID: 38012050 DOI: 10.1146/annurev-physchem-083122-011610] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2023]
Abstract
Attosecond science requires a substantial rethinking of how to make measurements on very short timescales; how to acquire the necessary equipment, technology, and personnel; and how to build a set of laboratories for such experiments. This entails a rejuvenation of the author in many respects, in the laboratory itself, with regard to students and postdocs, and in generating funding for research. It also brings up questions of what it means to do attosecond science, and the discovery of the power of X-ray spectroscopy itself, which complements the short timescales addressed. The lessons learned, expressed in the meanderings of this autobiographical article, may be of benefit to others who try to reinvent themselves.
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Affiliation(s)
- Stephen R Leone
- Departments of Chemistry and Physics and Lawrence Berkeley National Laboratory, University of California, Berkeley, California, USA;
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3
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Heim ZN, Neumark DM. Nonadiabatic Dynamics Studied by Liquid-Jet Time-Resolved Photoelectron Spectroscopy. Acc Chem Res 2022; 55:3652-3662. [PMID: 36480155 DOI: 10.1021/acs.accounts.2c00609] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The development of the liquid microjet technique by Faubel and co-workers has enabled the investigation of high vapor pressure liquids and solutions utilizing high-vacuum methods. One such method is photoelectron spectroscopy (PES), which allows one to probe the electronic properties of a sample through ionization in a state-specific manner. Liquid microjets consisting of pure solvents and solute-solvent systems have been studied with great success utilizing PES and, more recently, time-resolved PES (TRPES). Here, we discuss progress made over recent years in understanding the solvation and excited state dynamics of the solvated electron and nucleic acid constituents (NACs) using these methods, as well as the prospect for their future.The solvated electron is of particular interest in liquid microjet experiments as it represents the simplest solute system. Despite this simplicity, there were still many unresolved questions about its binding energy and excited state relaxation dynamics that are ideal problems for liquid microjet PES. In the work discussed in this Account, accurate binding energies were measured for the solvated electron in multiple high vapor pressure solvents. The advantages of liquid jet PES were further highlighted in the femtosecond excited state relaxation studies on the solvated electron in water where a 75 ± 20 fs lifetime attributable to internal conversion from the excited p-state to a hot ground state was measured, supporting a nonadiabatic relaxation mechanism.Nucleic acid constituents represent a class of important solutes with several unresolved questions that the liquid microjet PES method is uniquely suited to address. As TRPES is capable of tracking dynamics with state-specificity, it is ideal for instances where there are multiple excited states potentially involved in the dynamics. Time-resolved studies of NAC relaxation after excitation using ultraviolet light identified relaxation lifetimes from multiple excited states. The state-specific nature of the TRPES method allowed us to identify the lack of any signal attributable to the 1nπ* state in thymine derived NACs. The femtosecond time resolution of the technique also aided in identifying differences between the excited state lifetimes of thymidine and thymidine monophosphate. These have been interpreted, aided by molecular dynamics simulations, as an influence of conformational differences leading to a longer excited state lifetime in thymidine monophosphate.Finally, we discuss advances in tabletop light sources extending into the extreme ultraviolet and soft X-ray regimes that allow expansion of liquid jet TRPES to full valence band and potentially core level studies of solutes and pure liquids in liquid microjets. As most solutes have ground state binding energies in the range of 10 eV, observation of both excited state decay and ground state recovery using ultraviolet pump-ultraviolet probe TRPES has been intractable. With high-harmonic generation light sources, it will be possible to not only observe complete relaxation pathways for valence level dynamics but to also track dynamics with element specificity by probing core levels of the solute of interest.
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Affiliation(s)
- Zachary N Heim
- Department of Chemistry, University of California, Berkeley, California94720, United States
| | - Daniel M Neumark
- Department of Chemistry, University of California, Berkeley, California94720, United States.,Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California94720, United States
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4
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Svoboda V, Ram NB, Baykusheva D, Zindel D, Waters MDJ, Spenger B, Ochsner M, Herburger H, Stohner J, Wörner HJ. Femtosecond photoelectron circular dichroism of chemical reactions. SCIENCE ADVANCES 2022; 8:eabq2811. [PMID: 35857523 PMCID: PMC9286499 DOI: 10.1126/sciadv.abq2811] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/01/2022] [Accepted: 05/31/2022] [Indexed: 06/15/2023]
Abstract
Understanding the chirality of molecular reaction pathways is essential for a broad range of fundamental and applied sciences. However, the current ability to probe chirality on the time scale of primary processes underlying chemical reactions remains very limited. Here, we demonstrate time-resolved photoelectron circular dichroism (TRPECD) with ultrashort circularly polarized vacuum-ultraviolet (VUV) pulses from a tabletop source. We demonstrate the capabilities of VUV-TRPECD by resolving the chirality changes in time during the photodissociation of atomic iodine from two chiral molecules. We identify several general key features of TRPECD, which include the ability to probe dynamical chirality along the complete photochemical reaction path, the sensitivity to the local chirality of the evolving scattering potential, and the influence of electron scattering off dissociating photofragments. Our results are interpreted by comparison with high-level ab-initio calculations of transient PECDs from molecular photoionization calculations. Our experimental and theoretical techniques define a general approach to femtochirality.
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Affiliation(s)
- Vít Svoboda
- Laboratory of Physical Chemistry, ETH Zürich, 8093 Zürich, Switzerland
| | - Niraghatam Bhargava Ram
- Laboratory of Physical Chemistry, ETH Zürich, 8093 Zürich, Switzerland
- Department of Physics, Indian Institute of Science Education and Research–Bhopal, Bhauri, Bhopal 462066, India
| | | | - Daniel Zindel
- Laboratory of Physical Chemistry, ETH Zürich, 8093 Zürich, Switzerland
| | - Max D. J. Waters
- Laboratory of Physical Chemistry, ETH Zürich, 8093 Zürich, Switzerland
| | - Benjamin Spenger
- Institute of Chemistry and Biotechnology, Zurich University of Applied Sciences, Wädenswil 8820, Switzerland
| | - Manuel Ochsner
- Laboratory of Physical Chemistry, ETH Zürich, 8093 Zürich, Switzerland
| | - Holger Herburger
- Laboratory of Physical Chemistry, ETH Zürich, 8093 Zürich, Switzerland
| | - Jürgen Stohner
- Institute of Chemistry and Biotechnology, Zurich University of Applied Sciences, Wädenswil 8820, Switzerland
| | - Hans Jakob Wörner
- Laboratory of Physical Chemistry, ETH Zürich, 8093 Zürich, Switzerland
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5
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Loh ZH. Studies of Ultrafast Molecular Dynamics by Femtosecond Extreme Ultraviolet Absorption Spectroscopy. CHEM LETT 2021. [DOI: 10.1246/cl.200940] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Zhi-Heng Loh
- Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371, Singapore
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6
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Warne EM, Downes-Ward B, Woodhouse J, Parkes MA, Springate E, Pearcy PAJ, Zhang Y, Karras G, Wyatt AS, Chapman RT, Minns RS. Photodissociation dynamics of methyl iodide probed using femtosecond extreme ultraviolet photoelectron spectroscopy. Phys Chem Chem Phys 2020; 22:25695-25703. [DOI: 10.1039/d0cp03478a] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Femtosecond pump–probe photoelectron spectroscopy measurements using an extreme ultraviolet probe have been made on the photodissociation dynamics of UV (269 nm) excited CH3I.
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Affiliation(s)
- Emily M. Warne
- School of Chemistry
- University of Southampton
- Southampton SO17 1BJ
- UK
| | | | - Joanne Woodhouse
- School of Chemistry
- University of Southampton
- Southampton SO17 1BJ
- UK
| | | | - Emma Springate
- Central Laser Facility
- STFC Rutherford Appleton Laboratory
- Didcot
- UK
| | | | - Yu Zhang
- Central Laser Facility
- STFC Rutherford Appleton Laboratory
- Didcot
- UK
| | - Gabriel Karras
- Central Laser Facility
- STFC Rutherford Appleton Laboratory
- Didcot
- UK
| | - Adam S. Wyatt
- Central Laser Facility
- STFC Rutherford Appleton Laboratory
- Didcot
- UK
| | | | - Russell S. Minns
- School of Chemistry
- University of Southampton
- Southampton SO17 1BJ
- UK
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7
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Bayesian Analysis of Femtosecond Pump-Probe Photoelectron-Photoion Coincidence Spectra with Fluctuating Laser Intensities. ENTROPY 2019; 21:e21010093. [PMID: 33266809 PMCID: PMC7514205 DOI: 10.3390/e21010093] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/06/2018] [Revised: 01/10/2019] [Accepted: 01/16/2019] [Indexed: 11/17/2022]
Abstract
This paper employs Bayesian probability theory for analyzing data generated in femtosecond pump-probe photoelectron-photoion coincidence (PEPICO) experiments. These experiments allow investigating ultrafast dynamical processes in photoexcited molecules. Bayesian probability theory is consistently applied to data analysis problems occurring in these types of experiments such as background subtraction and false coincidences. We previously demonstrated that the Bayesian formalism has many advantages, amongst which are compensation of false coincidences, no overestimation of pump-only contributions, significantly increased signal-to-noise ratio, and applicability to any experimental situation and noise statistics. Most importantly, by accounting for false coincidences, our approach allows running experiments at higher ionization rates, resulting in an appreciable reduction of data acquisition times. In addition to our previous paper, we include fluctuating laser intensities, of which the straightforward implementation highlights yet another advantage of the Bayesian formalism. Our method is thoroughly scrutinized by challenging mock data, where we find a minor impact of laser fluctuations on false coincidences, yet a noteworthy influence on background subtraction. We apply our algorithm to data obtained in experiments and discuss the impact of laser fluctuations on the data analysis.
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8
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UV-Driven Harmonic Generation for Time-Resolved Photoelectron Spectroscopy of Polyatomic Molecules. APPLIED SCIENCES-BASEL 2018. [DOI: 10.3390/app8101784] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
A single-order harmonic pulse in the vacuum-ultraviolet (VUV) is highly desirable for time-resolved photoelectron spectroscopy (TRPES) of polyatomic molecules. A high-power 9th harmonic of a Ti:sapphire laser (hv = 14 eV) is obtained using a UV driving laser at 270 nm (the 3rd harmonic). We describe our recent efforts to develop VUV TRPES combined with UV-driven harmonic generation, and present a few representative results from our recent TRPES studies.
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9
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von Conta A, Tehlar A, Schletter A, Arasaki Y, Takatsuka K, Wörner HJ. Conical-intersection dynamics and ground-state chemistry probed by extreme-ultraviolet time-resolved photoelectron spectroscopy. Nat Commun 2018; 9:3162. [PMID: 30089780 PMCID: PMC6082858 DOI: 10.1038/s41467-018-05292-4] [Citation(s) in RCA: 41] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2018] [Accepted: 06/15/2018] [Indexed: 11/09/2022] Open
Abstract
Time-resolved photoelectron spectroscopy (TRPES) is a useful approach to elucidate the coupled electronic-nuclear quantum dynamics underlying chemical processes, but has remained limited by the use of low photon energies. Here, we demonstrate the general advantages of XUV-TRPES through an application to NO2, one of the simplest species displaying the complexity of a non-adiabatic photochemical process. The high photon energy enables ionization from the entire geometrical configuration space, giving access to the true dynamics of the system. Specifically, the technique reveals dynamics through a conical intersection, large-amplitude motion and photodissociation in the electronic ground state. XUV-TRPES simultaneously projects the excited-state wave packet onto many final states, offering a multi-dimensional view of the coupled electronic and nuclear dynamics. Our interpretations are supported by ab initio wavepacket calculations on new global potential-energy surfaces. The presented results contribute to establish XUV-TRPES as a powerful technique providing a complete picture of ultrafast chemical dynamics from photoexcitation to the final products.
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Affiliation(s)
- A von Conta
- Laboratory of Physical Chemistry, ETH Zurich, Vladimir-Prelog-Weg 2, CH-8093, Zurich, Switzerland
| | - A Tehlar
- Laboratory of Physical Chemistry, ETH Zurich, Vladimir-Prelog-Weg 2, CH-8093, Zurich, Switzerland
| | - A Schletter
- Laboratory of Physical Chemistry, ETH Zurich, Vladimir-Prelog-Weg 2, CH-8093, Zurich, Switzerland
| | - Y Arasaki
- Fukui Institute for Fundamental Chemistry, Kyoto University, Sakyo-ku, Kyoto, 606-8103, Japan
| | - K Takatsuka
- Fukui Institute for Fundamental Chemistry, Kyoto University, Sakyo-ku, Kyoto, 606-8103, Japan
| | - H J Wörner
- Laboratory of Physical Chemistry, ETH Zurich, Vladimir-Prelog-Weg 2, CH-8093, Zurich, Switzerland.
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10
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Tehlar A, von Conta A, Arasaki Y, Takatsuka K, Wörner HJ. Ab initio calculation of femtosecond-time-resolved photoelectron spectra of NO 2 after excitation to the A-band. J Chem Phys 2018; 149:034307. [PMID: 30037246 DOI: 10.1063/1.5029365] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
We present calculations of time-dependent photoelectron spectra of NO2 after excitation to the A-band for comparison with extreme-ultraviolet (XUV) time-resolved photoelectron spectroscopy. We employ newly calculated potential energy surfaces of the two lowest-lying coupled 2A' states obtained from multi-reference configuration-interaction calculations to propagate the photo-excited wave packet using a split-step-operator method. The propagation includes the nonadiabatic coupling of the potential surfaces as well as the explicit interaction with the pump pulse centered at 3.1 eV (400 nm). A semiclassical approach to calculate the time-dependent photoelectron spectrum arising from the ionization to the eight energetically lowest-lying states of the cation allows us to reproduce the static experimental spectrum up to a binding energy of 16 eV and enables direct comparisons with XUV time-resolved photoelectron spectroscopy.
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Affiliation(s)
- Andres Tehlar
- Laboratory for Physical Chemistry, ETH Zürich, Wolfgang-Pauli-Strasse 10, CH-8093 Zürich, Switzerland
| | - Aaron von Conta
- Laboratory for Physical Chemistry, ETH Zürich, Wolfgang-Pauli-Strasse 10, CH-8093 Zürich, Switzerland
| | - Yasuki Arasaki
- Fukui Institute for Fundamental Chemistry, Kyoto University, Sakyo-ku, Kyoto 606-8103, Japan
| | - Kazuo Takatsuka
- Fukui Institute for Fundamental Chemistry, Kyoto University, Sakyo-ku, Kyoto 606-8103, Japan
| | - Hans Jakob Wörner
- Laboratory for Physical Chemistry, ETH Zürich, Wolfgang-Pauli-Strasse 10, CH-8093 Zürich, Switzerland
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11
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Iikubo R, Sekikawa T, Harabuchi Y, Taketsugu T. Structural dynamics of photochemical reactions probed by time-resolved photoelectron spectroscopy using high harmonic pulses. Faraday Discuss 2018; 194:147-160. [PMID: 27711881 DOI: 10.1039/c6fd00063k] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Femtosecond ring-opening dynamics of 1,3-cyclohexadiene (CHD) in gas phase upon two-photon excitation at 400 nm (=3.1 eV) was investigated by time-resolved photoelectron spectroscopy using 42 nm (=29.5 eV) high harmonic photons probing the dynamics of the lower-lying occupied molecular orbitals (MOs), which are the fingerprints of the molecular structure. After 500 fs, the photoelectron intensity of the MO constituting the C[double bond, length as m-dash]C sigma bond (σC[double bond, length as m-dash]C) of CHD was enhanced, while that of the MO forming the C-C sigma bond (σCC) of CHD was decreased. The changes in the photoelectron spectra suggest that the ring of CHD opens to form a 1,3,5-hexatriene (HT) after 500 fs. The dynamics of the σC[double bond, length as m-dash]C and σCC bands between 200 and 500 fs reflects the ring deformation to a conical intersection between the 21A and 11A potential energy surfaces prior to the ring-opening reaction.
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Affiliation(s)
- Ryo Iikubo
- Department of Applied Physics, Faculty of Engineering, Hokkaido University, Kita 13 Nishi 8, Kita-ku, Sapporo 060-8628, Japan.
| | - Taro Sekikawa
- Department of Applied Physics, Faculty of Engineering, Hokkaido University, Kita 13 Nishi 8, Kita-ku, Sapporo 060-8628, Japan.
| | - Yu Harabuchi
- Department of Chemistry, Faculty of Science, Hokkaido University, Kita 10 Nishi 8, Kita-ku, Sapporo 060-0810, Japan
| | - Tetsuya Taketsugu
- Department of Chemistry, Faculty of Science, Hokkaido University, Kita 10 Nishi 8, Kita-ku, Sapporo 060-0810, Japan
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12
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Blanco M, Flores-Arias MT. Frequency gating to isolate single attosecond pulses with overdense plasmas using particle-in-cell simulations. OPTICS EXPRESS 2017; 25:13372-13381. [PMID: 28788874 DOI: 10.1364/oe.25.013372] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/20/2017] [Accepted: 05/29/2017] [Indexed: 06/07/2023]
Abstract
We present the isolation of single attosecond pulses for multi-cycle and few-cycle laser pulses from high harmonic generation in overdense plasmas, calculated with particle-in-cell simulations. By the combination of two laser pulses of equal amplitude and a small frequency shift between them, we demonstrate that it is possible to shorten the region in which the laser pulse is most intense, therefore restricting the generation of high harmonic orders in the form of attosecond pulses to a narrower time window. The creation of this window is achieved due to the combination of the laser pulse envelope and the slow oscillating wave obtained from the coherent sum of the two pulses. A parametric scan, performed with particle-in-cell simulations, reveals how the pulse isolation behaves for different input laser pulse lengths and which are the optimal frequency shifts between the two laser pulses in each case, giving the conditions for having a good isolation of an attosecond pulse when working with laser-plasma interaction in overdense targets.
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13
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Wernet P, Leitner T, Josefsson I, Mazza T, Miedema PS, Schröder H, Beye M, Kunnus K, Schreck S, Radcliffe P, Düsterer S, Meyer M, Odelius M, Föhlisch A. Communication: Direct evidence for sequential dissociation of gas-phase Fe(CO) 5 via a singlet pathway upon excitation at 266 nm. J Chem Phys 2017; 146:211103. [PMID: 28595420 PMCID: PMC5457291 DOI: 10.1063/1.4984774] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2017] [Accepted: 05/18/2017] [Indexed: 11/14/2022] Open
Abstract
We prove the hitherto hypothesized sequential dissociation of Fe(CO)5 in the gas phase upon photoexcitation at 266 nm via a singlet pathway with time-resolved valence and core-level photoelectron spectroscopy with an x-ray free-electron laser. Valence photoelectron spectra are used to identify free CO molecules and to determine the time constants of stepwise dissociation to Fe(CO)4 within the temporal resolution of the experiment and further to Fe(CO)3 within 3 ps. Fe 3p core-level photoelectron spectra directly reflect the singlet spin state of the Fe center in Fe(CO)5, Fe(CO)4, and Fe(CO)3 showing that the dissociation exclusively occurs along a singlet pathway without triplet-state contribution. Our results are important for assessing intra- and intermolecular relaxation processes in the photodissociation dynamics of the prototypical Fe(CO)5 complex in the gas phase and in solution, and they establish time-resolved core-level photoelectron spectroscopy as a powerful tool for determining the multiplicity of transition metals in photochemical reactions of coordination complexes.
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Affiliation(s)
- Ph Wernet
- Institute for Methods and Instrumentation for Synchrotron Radiation Research, Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Albert-Einstein-Strasse 15, 12489 Berlin, Germany
| | - T Leitner
- Institute for Methods and Instrumentation for Synchrotron Radiation Research, Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Albert-Einstein-Strasse 15, 12489 Berlin, Germany
| | - I Josefsson
- Department of Physics, Stockholm University, AlbaNova University Center, 106 91 Stockholm, Sweden
| | - T Mazza
- European XFEL GmbH, Holzkoppel 4, 22869 Schenefeld, Germany
| | - P S Miedema
- Institute for Methods and Instrumentation for Synchrotron Radiation Research, Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Albert-Einstein-Strasse 15, 12489 Berlin, Germany
| | - H Schröder
- Institute for Methods and Instrumentation for Synchrotron Radiation Research, Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Albert-Einstein-Strasse 15, 12489 Berlin, Germany
| | - M Beye
- Institute for Methods and Instrumentation for Synchrotron Radiation Research, Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Albert-Einstein-Strasse 15, 12489 Berlin, Germany
| | - K Kunnus
- Institute for Methods and Instrumentation for Synchrotron Radiation Research, Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Albert-Einstein-Strasse 15, 12489 Berlin, Germany
| | - S Schreck
- Institute for Methods and Instrumentation for Synchrotron Radiation Research, Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Albert-Einstein-Strasse 15, 12489 Berlin, Germany
| | - P Radcliffe
- European XFEL GmbH, Holzkoppel 4, 22869 Schenefeld, Germany
| | - S Düsterer
- Deutsches Elektronen-Synchrotron DESY, Notkestrasse 85, 22607 Hamburg, Germany
| | - M Meyer
- European XFEL GmbH, Holzkoppel 4, 22869 Schenefeld, Germany
| | - M Odelius
- Department of Physics, Stockholm University, AlbaNova University Center, 106 91 Stockholm, Sweden
| | - A Föhlisch
- Institute for Methods and Instrumentation for Synchrotron Radiation Research, Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Albert-Einstein-Strasse 15, 12489 Berlin, Germany
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14
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Svoboda V, Ram NB, Rajeev R, Wörner HJ. Time-resolved photoelectron imaging with a femtosecond vacuum-ultraviolet light source: Dynamics in the A∼/B∼- and F∼-bands of SO 2. J Chem Phys 2017; 146:084301. [PMID: 28249458 DOI: 10.1063/1.4976552] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Time-resolved photoelectron imaging is demonstrated using the third harmonic of a 400-nm femtosecond laser pulse as the ionization source. The resulting 133-nm pulses are combined with 266-nm pulses to study the excited-state dynamics in the A∼/B∼- and F∼-band regions of SO2. The photoelectron signal from the molecules excited to the A∼/B∼-band does not decay for at least several picoseconds, reflecting the population of bound states. The temporal variation of the photoelectron angular distribution (PAD) reflects the creation of a rotational wave packet in the excited state. In contrast, the photoelectron signal from molecules excited to the F∼-band decays with a time constant of 80 fs. This time constant is attributed to the motion of the excited-state wave packet out of the ionization window. The observed time-dependent PADs are consistent with the F∼ band corresponding to a Rydberg state of dominant s character. These results establish low-order harmonic generation as a promising tool for time-resolved photoelectron imaging of the excited-state dynamics of molecules, simultaneously giving access to low-lying electronic states, as well as Rydberg states, and avoiding the ionization of unexcited molecules.
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Affiliation(s)
- Vít Svoboda
- Laboratory of Physical Chemistry, ETH Zurich, Vladimir-Prelog-Weg 2, CH-8093 Zurich, Switzerland
| | - Niraghatam Bhargava Ram
- Laboratory of Physical Chemistry, ETH Zurich, Vladimir-Prelog-Weg 2, CH-8093 Zurich, Switzerland
| | - Rajendran Rajeev
- Laboratory of Physical Chemistry, ETH Zurich, Vladimir-Prelog-Weg 2, CH-8093 Zurich, Switzerland
| | - Hans Jakob Wörner
- Laboratory of Physical Chemistry, ETH Zurich, Vladimir-Prelog-Weg 2, CH-8093 Zurich, Switzerland
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15
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Arbelo Y, Bleiner D. Induction spectrometry using an ultrafast hollow-cored toroidal-coil (HTC) detector. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2017; 88:024710. [PMID: 28249469 DOI: 10.1063/1.4975402] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Ultrafast photoelectron and photoion spectroscopy (as well as their combination known as "coincidence spectroscopy") utilizes detectors based on different electron multipliers such as microchannel plates or single-channel electron multipliers. These detectors have a few important limitations such as fast-signal distortion (low pass operation), mutually exclusive positive or negative mode, dead time, and requirement of trigger. A high-pass induction detector, based on a hollow-cored toroidal coil, was developed that overcomes the above-mentioned limitations. The frequency-dispersive response and linearity of different configurations were analyzed. It is shown that the response is enhanced for ultrafast electron signals, dependent on construction parameters, thus offering response flexibility by design. Kinetic energy distributions of pseudospark-induced electron pulses are characterized in order to validate the capabilities in real applications.
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Affiliation(s)
- Yunieski Arbelo
- Swiss Federal Laboratories for Materials Science and Technology (Empa), Überlandstrasse 129, CH-8600 Dübendorf, Switzerland
| | - Davide Bleiner
- Swiss Federal Laboratories for Materials Science and Technology (Empa), Überlandstrasse 129, CH-8600 Dübendorf, Switzerland
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16
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Fushitani M, Hishikawa A. Single-order laser high harmonics in XUV for ultrafast photoelectron spectroscopy of molecular wavepacket dynamics. STRUCTURAL DYNAMICS (MELVILLE, N.Y.) 2016; 3:062602. [PMID: 27795976 PMCID: PMC5065577 DOI: 10.1063/1.4964775] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/12/2016] [Accepted: 09/29/2016] [Indexed: 06/06/2023]
Abstract
We present applications of extreme ultraviolet (XUV) single-order laser harmonics to gas-phase ultrafast photoelectron spectroscopy. Ultrashort XUV pulses at 80 nm are obtained as the 5th order harmonics of the fundamental laser at 400 nm by using Xe or Kr as the nonlinear medium and separated from other harmonic orders by using an indium foil. The single-order laser harmonics is applied for real-time probing of vibrational wavepacket dynamics of I2 molecules in the bound and dissociating low-lying electronic states and electronic-vibrational wavepacket dynamics of highly excited Rydberg N2 molecules.
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Affiliation(s)
- Mizuho Fushitani
- Department of Chemistry, Nagoya University , Furo-cho, Chikusa, Nagoya, Aichi 464-8602, Japan
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17
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Rajeev R, Hellwagner J, Schumacher A, Jordan I, Huppert M, Tehlar A, Niraghatam BR, Baykusheva D, Lin N, von Conta A, Wörner HJ. In situ frequency gating and beam splitting of vacuum- and extreme-ultraviolet pulses. LIGHT, SCIENCE & APPLICATIONS 2016; 5:e16170. [PMID: 30167130 PMCID: PMC6059825 DOI: 10.1038/lsa.2016.170] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/14/2016] [Revised: 05/22/2016] [Accepted: 05/31/2016] [Indexed: 05/28/2023]
Abstract
Monochromatization of high-harmonic sources has opened fascinating perspectives regarding time-resolved photoemission from all phases of matter. Such studies have invariably involved the use of spectral filters or spectrally dispersive optical components that are inherently lossy and technically complex. Here we present a new technique for the spectral selection of near-threshold harmonics and their spatial separation from the driving beams without any optical elements. We discover the existence of a narrow phase-matching gate resulting from the combination of the non-collinear generation geometry in an extended medium, atomic resonances and absorption. Our technique offers a filter contrast of up to 104 for the selected harmonics against the adjacent ones and offers multiple temporally synchronized beamlets in a single unified scheme. We demonstrate the selective generation of 133, 80 or 56 nm femtosecond pulses from a 400-nm driver, which is specific to the target gas. These results open new pathways towards phase-sensitive multi-pulse spectroscopy in the vacuum- and extreme-ultraviolet, and frequency-selective output coupling from enhancement cavities.
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18
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Smith AD, Watts HM, Jager E, Horke DA, Springate E, Alexander O, Cacho C, Chapman RT, Minns RS. Resonant multiphoton ionisation probe of the photodissociation dynamics of ammonia. Phys Chem Chem Phys 2016; 18:28150-28156. [PMID: 27722319 DOI: 10.1039/c6cp05279g] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The dissociation dynamics of the Ã-state of ammonia have been studied using a resonant multiphoton ionisation probe in a photoelectron spectroscopy experiment. The use of a resonant intermediate in the multiphoton ionisation process changes the ionisation propensity, allowing access to different ion states when compared with equivalent single photon ionisation experiments. Ionisation through the E' 1A1' Rydberg intermediate means we maintain overlap with the ion state for an extended period, allowing us to monitor the excited state population for several hundred femtoseconds. The vibrational states in the photoelectron spectrum show two distinct timescales, 200 fs and 320 fs, that we assign to the non-adiabatic and adiabatic dissociation processes respectively. The different timescales derive from differences in the wavepacket trajectories for the two dissociation pathways that resonantly excite different vibrational states in the intermediate Rydberg state. The timescales are similar to those obtained from time resolved ion kinetic energy release measurements, suggesting we can measure the different trajectories taken out to the region of conical intersection.
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Affiliation(s)
- Adam D Smith
- Chemistry, University of Southampton, Highfield, Southampton SO17 1BJ, UK.
| | - Hannah M Watts
- Chemistry, University of Southampton, Highfield, Southampton SO17 1BJ, UK.
| | - Edward Jager
- Chemistry, University of Southampton, Highfield, Southampton SO17 1BJ, UK.
| | - Daniel A Horke
- Center for Free-Electron Laser Science, DESY, Notkestrasse 85, 22607 Hamburg, Germany
| | - Emma Springate
- Central Laser Facility, STFC Rutherford Appleton Laboratory, Didcot, Oxfordshire OX11 0QX, UK
| | - Oliver Alexander
- Central Laser Facility, STFC Rutherford Appleton Laboratory, Didcot, Oxfordshire OX11 0QX, UK
| | - Cephise Cacho
- Central Laser Facility, STFC Rutherford Appleton Laboratory, Didcot, Oxfordshire OX11 0QX, UK
| | - Richard T Chapman
- Central Laser Facility, STFC Rutherford Appleton Laboratory, Didcot, Oxfordshire OX11 0QX, UK
| | - Russell S Minns
- Chemistry, University of Southampton, Highfield, Southampton SO17 1BJ, UK.
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19
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von Conta A, Huppert M, Wörner HJ. A table-top monochromator for tunable femtosecond XUV pulses generated in a semi-infinite gas cell: Experiment and simulations. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2016; 87:073102. [PMID: 27475543 DOI: 10.1063/1.4955263] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/03/2016] [Accepted: 06/22/2016] [Indexed: 05/19/2023]
Abstract
We present a new design of a time-preserving extreme-ultraviolet (XUV) monochromator using a semi-infinite gas cell as a source. The performance of this beamline in the photon-energy range of 20 eV-42 eV has been characterized. We have measured the order-dependent XUV pulse durations as well as the flux and the spectral contrast. XUV pulse durations of ≤40 fs using 32 fs, 800 nm driving pulses were measured on the target. The spectral contrast was better than 100 over the entire energy range. A simple model based on the strong-field approximation is presented to estimate different contributions to the measured XUV pulse duration. On-axis phase-matching calculations are used to rationalize the variation of the photon flux with pressure and intensity.
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Affiliation(s)
- A von Conta
- Laboratorium für Physikalische Chemie, ETH Zürich, Vladimir-Prelog-Weg 2, CH-8093 Zürich, Switzerland
| | - M Huppert
- Laboratorium für Physikalische Chemie, ETH Zürich, Vladimir-Prelog-Weg 2, CH-8093 Zürich, Switzerland
| | - H J Wörner
- Laboratorium für Physikalische Chemie, ETH Zürich, Vladimir-Prelog-Weg 2, CH-8093 Zürich, Switzerland
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20
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Iikubo R, Fujiwara T, Sekikawa T, Harabuchi Y, Satoh S, Taketsugu T, Kayanuma Y. Time-Resolved Photoelectron Spectroscopy of Dissociating 1,2-Butadiene Molecules by High Harmonic Pulses. J Phys Chem Lett 2015; 6:2463-2468. [PMID: 26266720 DOI: 10.1021/acs.jpclett.5b00943] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Using 42 nm high harmonic pulses, the dissociation dynamics of 1,2-butadiene was investigated by time-resolved photoelectron spectroscopy (TRPES), enabling us to observe dynamical changes of multiple molecular orbitals (MOs) with higher temporal resolution than conventional light sources. Because each lower-lying occupied MO has particular spatial electron distribution, the structural dynamics of photochemical reaction can be revealed. On the femtosecond time scale, a short-lived excited state with a lifetime of 37 ± 15 fs and the coherent oscillation of the photoelectron yield stimulated by Hertzberg-Teller coupling were observed. Ab initio molecular dynamics simulations in the electronically excited state find three relaxation pathways from the vertically excited structure in S1 to the ground state, and one of them is the dominant relaxation pathway, observed as the short-lived excited state. On the picosecond time scale, the photoelectron yields related to the C-C bond decreased upon photoexcitation, indicating C-C bond cleavage.
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Affiliation(s)
- Ryo Iikubo
- †Department of Applied Physics, Faculty of Engineering, Hokkaido University, Kita 13 Nishi 8, Kita-ku, Sapporo 060-8628, Japan
| | - Takehisa Fujiwara
- †Department of Applied Physics, Faculty of Engineering, Hokkaido University, Kita 13 Nishi 8, Kita-ku, Sapporo 060-8628, Japan
| | - Taro Sekikawa
- †Department of Applied Physics, Faculty of Engineering, Hokkaido University, Kita 13 Nishi 8, Kita-ku, Sapporo 060-8628, Japan
| | - Yu Harabuchi
- ‡Department of Chemistry, Faculty of Science, Hokkaido University, Kita 10 Nishi 8, Kita-ku, Sapporo 060-0810, Japan
| | - Sota Satoh
- ‡Department of Chemistry, Faculty of Science, Hokkaido University, Kita 10 Nishi 8, Kita-ku, Sapporo 060-0810, Japan
| | - Tetsuya Taketsugu
- ‡Department of Chemistry, Faculty of Science, Hokkaido University, Kita 10 Nishi 8, Kita-ku, Sapporo 060-0810, Japan
| | - Yosuke Kayanuma
- §Materials and Structures Laboratory, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, Yokohama 226-8503, Japan
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21
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Weber SJ, Manschwetus B, Billon M, Böttcher M, Bougeard M, Breger P, Géléoc M, Gruson V, Huetz A, Lin N, Picard YJ, Ruchon T, Salières P, Carré B. Flexible attosecond beamline for high harmonic spectroscopy and XUV/near-IR pump probe experiments requiring long acquisition times. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2015; 86:033108. [PMID: 25832212 DOI: 10.1063/1.4914464] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
We describe the versatile features of the attosecond beamline recently installed at CEA-Saclay on the PLFA kHz laser. It combines a fine and very complete set of diagnostics enabling high harmonic spectroscopy (HHS) through the advanced characterization of the amplitude, phase, and polarization of the harmonic emission. It also allows a variety of photo-ionization experiments using magnetic bottle and COLTRIMS (COLd Target Recoil Ion Momentum Microscopy) electron spectrometers that may be used simultaneously, thanks to a two-foci configuration. Using both passive and active stabilization, special care was paid to the long term stability of the system to allow, using both experimental approaches, time resolved studies with attosecond precision, typically over several hours of acquisition times. As an illustration, applications to multi-orbital HHS and electron-ion coincidence time resolved spectroscopy are presented.
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Affiliation(s)
- S J Weber
- Commissariat l'Energie Atomique, Laser, Interactions and Dynamics Laboratory (LIDyL), DSM/IRAMIS, CEA-Saclay, 91191 Gif sur Yvette, France
| | - B Manschwetus
- Commissariat l'Energie Atomique, Laser, Interactions and Dynamics Laboratory (LIDyL), DSM/IRAMIS, CEA-Saclay, 91191 Gif sur Yvette, France
| | - M Billon
- Commissariat l'Energie Atomique, Laser, Interactions and Dynamics Laboratory (LIDyL), DSM/IRAMIS, CEA-Saclay, 91191 Gif sur Yvette, France
| | - M Böttcher
- ISMO, UMR 8214, Université Paris-Sud, Batiment 350, Orsay, France
| | - M Bougeard
- Commissariat l'Energie Atomique, Laser, Interactions and Dynamics Laboratory (LIDyL), DSM/IRAMIS, CEA-Saclay, 91191 Gif sur Yvette, France
| | - P Breger
- Commissariat l'Energie Atomique, Laser, Interactions and Dynamics Laboratory (LIDyL), DSM/IRAMIS, CEA-Saclay, 91191 Gif sur Yvette, France
| | - M Géléoc
- Commissariat l'Energie Atomique, Laser, Interactions and Dynamics Laboratory (LIDyL), DSM/IRAMIS, CEA-Saclay, 91191 Gif sur Yvette, France
| | - V Gruson
- Commissariat l'Energie Atomique, Laser, Interactions and Dynamics Laboratory (LIDyL), DSM/IRAMIS, CEA-Saclay, 91191 Gif sur Yvette, France
| | - A Huetz
- ISMO, UMR 8214, Université Paris-Sud, Batiment 350, Orsay, France
| | - N Lin
- Commissariat l'Energie Atomique, Laser, Interactions and Dynamics Laboratory (LIDyL), DSM/IRAMIS, CEA-Saclay, 91191 Gif sur Yvette, France
| | - Y J Picard
- ISMO, UMR 8214, Université Paris-Sud, Batiment 350, Orsay, France
| | - T Ruchon
- Commissariat l'Energie Atomique, Laser, Interactions and Dynamics Laboratory (LIDyL), DSM/IRAMIS, CEA-Saclay, 91191 Gif sur Yvette, France
| | - P Salières
- Commissariat l'Energie Atomique, Laser, Interactions and Dynamics Laboratory (LIDyL), DSM/IRAMIS, CEA-Saclay, 91191 Gif sur Yvette, France
| | - B Carré
- Commissariat l'Energie Atomique, Laser, Interactions and Dynamics Laboratory (LIDyL), DSM/IRAMIS, CEA-Saclay, 91191 Gif sur Yvette, France
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22
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Ziemkiewicz MP, Bacellar C, Siefermann KR, Leone SR, Neumark DM, Gessner O. Femtosecond time-resolved XUV + UV photoelectron imaging of pure helium nanodroplets. J Chem Phys 2014; 141:174306. [DOI: 10.1063/1.4900503] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Affiliation(s)
- Michael P. Ziemkiewicz
- Ultrafast X-ray Science Laboratory, Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
- Department of Chemistry, University of California, Berkeley, California 94720, USA
| | - Camila Bacellar
- Ultrafast X-ray Science Laboratory, Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
- Department of Chemistry, University of California, Berkeley, California 94720, USA
| | - Katrin R. Siefermann
- Ultrafast X-ray Science Laboratory, Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
- Department of Chemistry, University of California, Berkeley, California 94720, USA
| | - Stephen R. Leone
- Ultrafast X-ray Science Laboratory, Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
- Department of Chemistry, University of California, Berkeley, California 94720, USA
- Department of Physics, University of California, Berkeley, California 94720, USA
| | - Daniel M. Neumark
- Ultrafast X-ray Science Laboratory, Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
- Department of Chemistry, University of California, Berkeley, California 94720, USA
| | - Oliver Gessner
- Ultrafast X-ray Science Laboratory, Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
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23
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Shavorskiy A, Neppl S, Slaughter DS, Cryan JP, Siefermann KR, Weise F, Lin MF, Bacellar C, Ziemkiewicz MP, Zegkinoglou I, Fraund MW, Khurmi C, Hertlein MP, Wright TW, Huse N, Schoenlein RW, Tyliszczak T, Coslovich G, Robinson J, Kaindl RA, Rude BS, Ölsner A, Mähl S, Bluhm H, Gessner O. Sub-nanosecond time-resolved ambient-pressure X-ray photoelectron spectroscopy setup for pulsed and constant wave X-ray light sources. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2014; 85:093102. [PMID: 25273702 DOI: 10.1063/1.4894208] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
An apparatus for sub-nanosecond time-resolved ambient-pressure X-ray photoelectron spectroscopy studies with pulsed and constant wave X-ray light sources is presented. A differentially pumped hemispherical electron analyzer is equipped with a delay-line detector that simultaneously records the position and arrival time of every single electron at the exit aperture of the hemisphere with ~0.1 mm spatial resolution and ~150 ps temporal accuracy. The kinetic energies of the photoelectrons are encoded in the hit positions along the dispersive axis of the two-dimensional detector. Pump-probe time-delays are provided by the electron arrival times relative to the pump pulse timing. An average time-resolution of (780 ± 20) ps (FWHM) is demonstrated for a hemisphere pass energy E(p) = 150 eV and an electron kinetic energy range KE = 503-508 eV. The time-resolution of the setup is limited by the electron time-of-flight (TOF) spread related to the electron trajectory distribution within the analyzer hemisphere and within the electrostatic lens system that images the interaction volume onto the hemisphere entrance slit. The TOF spread for electrons with KE = 430 eV varies between ~9 ns at a pass energy of 50 eV and ~1 ns at pass energies between 200 eV and 400 eV. The correlation between the retarding ratio and the TOF spread is evaluated by means of both analytical descriptions of the electron trajectories within the analyzer hemisphere and computer simulations of the entire trajectories including the electrostatic lens system. In agreement with previous studies, we find that the by far dominant contribution to the TOF spread is acquired within the hemisphere. However, both experiment and computer simulations show that the lens system indirectly affects the time resolution of the setup to a significant extent by inducing a strong dependence of the angular spread of electron trajectories entering the hemisphere on the retarding ratio. The scaling of the angular spread with the retarding ratio can be well approximated by applying Liouville's theorem of constant emittance to the electron trajectories inside the lens system. The performance of the setup is demonstrated by characterizing the laser fluence-dependent transient surface photovoltage response of a laser-excited Si(100) sample.
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Affiliation(s)
- Andrey Shavorskiy
- Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Stefan Neppl
- Ultrafast X-ray Science Laboratory, Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Daniel S Slaughter
- Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - James P Cryan
- Ultrafast X-ray Science Laboratory, Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Katrin R Siefermann
- Ultrafast X-ray Science Laboratory, Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Fabian Weise
- Ultrafast X-ray Science Laboratory, Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Ming-Fu Lin
- Ultrafast X-ray Science Laboratory, Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Camila Bacellar
- Ultrafast X-ray Science Laboratory, Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Michael P Ziemkiewicz
- Ultrafast X-ray Science Laboratory, Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Ioannis Zegkinoglou
- Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Matthew W Fraund
- Ultrafast X-ray Science Laboratory, Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Champak Khurmi
- Ultrafast X-ray Science Laboratory, Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Marcus P Hertlein
- Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Travis W Wright
- Ultrafast X-ray Science Laboratory, Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Nils Huse
- Ultrafast X-ray Science Laboratory, Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Robert W Schoenlein
- Ultrafast X-ray Science Laboratory, Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Tolek Tyliszczak
- Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Giacomo Coslovich
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Joseph Robinson
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Robert A Kaindl
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Bruce S Rude
- Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | | | - Sven Mähl
- SPECS Surface Nano Analysis GmbH, 13355 Berlin, Germany
| | - Hendrik Bluhm
- Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Oliver Gessner
- Ultrafast X-ray Science Laboratory, Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
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24
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Gomes JDS, Gargano R, Martins JBL, M de Macedo LG. Relativistic four-component potential energy curves for the lowest 23 covalent states of molecular bromine (Br2). J Phys Chem A 2014; 118:5818-22. [PMID: 24779448 DOI: 10.1021/jp4114283] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The covalent excited states and ground state of the Br2 molecule has been investigated by using four-component relativistic COSCI and MRCISD methods. These methods were performed for all covalent states in the representation Ω((±)). Calculated potential energy curves (PECs) were obtained at the four-component COSCI level, and spectroscopic constants (R(e), D(e), D0, ω(e), ω(e)x(e), ω(e)y(e), B(e), α(e), γ(e), Te, Dv) for bounded states are reported. The vertical excitations for all covalent states are reported at COSCI, MRCISD, and MRCISD+Q levels. We also present spectroscopic constants for two weakly bounded states (A':(1)2u and B':(1)0(-)u) not yet reported in the literature, as well as accurate analytical curves for all five relativistic molecular bounded sates [the ground state X:0 g(+) and the excited states A:(1)1(u), B:(1)0(u)(+), C:(2)1(u), and B':(1)0(u)(-)] found in this work.
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Affiliation(s)
- José da Silva Gomes
- Faculdade de Biotecnologia, Instituto de Ciências Biológicas, Universidade Federal do Pará (UFPA) , Belém, Pará 66075-110, Brazil
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25
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Makida A, Igarashi H, Fujiwara T, Sekikawa T, Harabuchi Y, Taketsugu T. Ultrafast Relaxation Dynamics in trans-1,3-Butadiene Studied by Time-Resolved Photoelectron Spectroscopy with High Harmonic Pulses. J Phys Chem Lett 2014; 5:1760-1765. [PMID: 26270380 DOI: 10.1021/jz5003567] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
In trans-1,3-butadiene, the ultrafast relaxation from the doubly excited state 2(1)Ag and the corresponding recovery of the ground state 1(1)Ag were observed simultaneously for the first time by time-resolved photoelectron spectroscopy (TRPES) using 29.5 eV high harmonic pulses. The fast recovery of 1(1)Ag shows that the following dissociation upon photoexcitation takes place after returning to the ground state. At 427 fs after photoexcitation, only the ionization energy from the C═C σ bond was found to remain shifted. Accompanying theoretical calculations with an assumption of Koopmans' theorem show that the ionization energy of the C═C σ bond is modulated by vibrational excitation of the antisymmetric C═C stretching mode. TRPES by high harmonics can probe the changes in the molecular structure sensitively.
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Affiliation(s)
- Ayumu Makida
- †Department of Applied Physics, Faculty of Engineering, Hokkaido University, Kita 13 Nishi 8, Kita-ku, Sapporo 060-8628, Japan
| | - Hironori Igarashi
- †Department of Applied Physics, Faculty of Engineering, Hokkaido University, Kita 13 Nishi 8, Kita-ku, Sapporo 060-8628, Japan
| | - Takehisa Fujiwara
- †Department of Applied Physics, Faculty of Engineering, Hokkaido University, Kita 13 Nishi 8, Kita-ku, Sapporo 060-8628, Japan
| | - Taro Sekikawa
- †Department of Applied Physics, Faculty of Engineering, Hokkaido University, Kita 13 Nishi 8, Kita-ku, Sapporo 060-8628, Japan
| | - Yu Harabuchi
- ‡Department of Chemistry, Faculty of Science, Hokkaido University, Kita 10 Nishi 8, Kita-ku, Sapporo 060-0810, Japan
| | - Tetsuya Taketsugu
- ‡Department of Chemistry, Faculty of Science, Hokkaido University, Kita 10 Nishi 8, Kita-ku, Sapporo 060-0810, Japan
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26
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Metje J, Borgwardt M, Moguilevski A, Kothe A, Engel N, Wilke M, Al-Obaidi R, Tolksdorf D, Firsov A, Brzhezinskaya M, Erko A, Kiyan IY, Aziz EF. Monochromatization of femtosecond XUV light pulses with the use of reflection zone plates. OPTICS EXPRESS 2014; 22:10747-60. [PMID: 24921776 DOI: 10.1364/oe.22.010747] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
We report on a newly built laser-based tabletop setup which enables generation of femtosecond light pulses in the XUV range employing the process of high-order harmonic generation (HHG) in a gas medium. The spatial, spectral, and temporal characteristics of the XUV beam are presented. Monochromatization of XUV light with minimum temporal pulse distortion is the central issue of this work. Off-center reflection zone plates are shown to be advantageous when selection of a desired harmonic is carried out with the use of a single optical element. A cross correlation technique was applied to characterize the performance of the zone plates in the time domain. By using laser pulses of 25 fs length to pump the HHG process, a pulse duration of 45 fs for monochromatized harmonics was achieved in the present setup.
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27
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Ibek M, Leitner T, Erko A, Firsov A, Wernet P. Monochromatizing and focussing femtosecond high-order harmonic radiation with one optical element. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2013; 84:103102. [PMID: 24182096 DOI: 10.1063/1.4822114] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
A novel approach for monochromatizing and focussing the Vacuum-Ultraviolet and soft x-ray radiation from high-order harmonic generation of a femtosecond optical laser with only one optical element is presented. We demonstrate that off-axis reflection zone plates applied as focussing monochromators allow for efficiently optimizing the trade-off between energy resolution and temporal dispersion of the femtosecond pulses. In the current experimental realization, we show how the temporal dispersion can be varied between 2 fs and 16 fs with a correlating variation of the energy resolution E/ΔE between 20 and 90 for an off-axis reflection zone plate optimized for harmonic 13 at 20.41 eV. We also show how the focal spot size varies correspondingly between 80 × 90 μm(2) and 290 × 140 μm(2) as determined with a computational fitting approach based on a 3D Gaussian model. The diffraction efficiency for the tested zone plates amounts to up to 10%. We furthermore evaluate the influence of pointing stability on the performance of the zone plates. Based on our results we propose an optimized realization of a dedicated beam line for femtosecond pulses from high-order harmonic generation with an off-axis reflection zone plate.
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Affiliation(s)
- Mateusz Ibek
- Institute for Methods and Instrumentation for Synchrotron Radiation Research, Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Albert-Einstein-Str. 15, 12489 Berlin, Germany
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28
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Chatterley AS, Roberts GM, Stavros VG. Timescales for adiabatic photodissociation dynamics from the à state of ammonia. J Chem Phys 2013; 139:034318. [DOI: 10.1063/1.4811672] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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29
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Tehlar A, Wörner HJ. Time-resolved high-harmonic spectroscopy of the photodissociation of CH3I and CF3I. Mol Phys 2013. [DOI: 10.1080/00268976.2013.782439] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Affiliation(s)
- A. Tehlar
- Laboratorium für Physikalische Chemie, , ETH Zürich, Switzerland
| | - H. J. Wörner
- Laboratorium für Physikalische Chemie, , ETH Zürich, Switzerland
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30
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Loh ZH, Leone SR. Capturing Ultrafast Quantum Dynamics with Femtosecond and Attosecond X-ray Core-Level Absorption Spectroscopy. J Phys Chem Lett 2013; 4:292-302. [PMID: 26283437 DOI: 10.1021/jz301910n] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Recent technical advances in ultrafast laser sources enable the generation of femtosecond and attosecond soft X-ray pulses in tabletop laser setups as well as accelerator-based synchrotron and free-electron laser sources. These new light sources can be harnessed via pump-probe spectroscopy to elucidate ultrafast quantum dynamics in atoms, molecules, and condensed matter with unprecedented time resolution and chemical sensitivity. Employing such ultrashort pulses in transient X-ray absorption spectroscopy combines the unique advantages of core-level absorption probing of chemical environments and oxidation states with the ability to obtain ultimately freeze-frame snapshots of electronic and nuclear dynamics. In this Perspective, we provide an overview of the progress in applying the recently developed technique of femtosecond to attosecond time-resolved soft X-ray transient absorption spectroscopy to the study of ultrafast phenomena, including some of our own efforts to elucidate the interaction of intense laser pulses with atoms and molecules in the strong-field, nonperturbative limit. Possible avenues for future work are outlined.
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Affiliation(s)
- Zhi-Heng Loh
- †Division of Chemistry and Biological Chemistry, and Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371, Singapore
| | - Stephen R Leone
- ‡Departments of Chemistry and Physics, University of California, Berkeley, California 94720, United States
- §Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
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31
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Bünermann O, Kornilov O, Haxton DJ, Leone SR, Neumark DM, Gessner O. Ultrafast probing of ejection dynamics of Rydberg atoms and molecular fragments from electronically excited helium nanodroplets. J Chem Phys 2012; 137:214302. [DOI: 10.1063/1.4768422] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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32
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Adachi S, Horio T, Suzuki T. Generation of intense single-order harmonic pulse in the vacuum ultraviolet region using a deep ultraviolet driving laser. OPTICS LETTERS 2012; 37:2118-2120. [PMID: 22660140 DOI: 10.1364/ol.37.002118] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
A 90 nm single-order harmonic pulse with a 200 nJ on-target pulse energy at 1 kHz was realized through a harmonic generation process with a 35 fs Ti:Sa third harmonic in a Kr gas cell.
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Affiliation(s)
- Shunsuke Adachi
- Department of Chemistry, Graduate School of Science, Kyoto University, Kyoto 606-8502, Japan. ‑u.ac.jp
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33
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Igarashi H, Makida A, Ito M, Sekikawa T. Pulse compression of phase-matched high harmonic pulses from a time-delay compensated monochromator. OPTICS EXPRESS 2012; 20:3725-3732. [PMID: 22418130 DOI: 10.1364/oe.20.003725] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Single 32.6 eV high harmonic pulses from a time-delay compensated monochromator were compressed down to 11 ± 3 fs by completely compensating for the pulse-front tilt. The photon flux was intensified up to 5.7×10(9) photons/s on target by implementing high harmonic generation under a phase matching condition in a hollow fiber used for increasing the interaction length. The output photon flux on target from the monochromator was comparable to that from a small synchrotron facility, while the pulse duration was more than three orders of magnitude shorter. This high harmonic beam line fulfills two requirements for time-resolved spectroscopy in extreme ultraviolet region, namely, ultrashort pulses and high photon flux.
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Affiliation(s)
- Hironori Igarashi
- Department of Applied Physics, Hokkaido University, Kita 13 Nishi 8, Kita-ku, Sapporo 060-8628, Japan
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34
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Faubel M, Siefermann KR, Liu Y, Abel B. Ultrafast soft X-ray photoelectron spectroscopy at liquid water microjets. Acc Chem Res 2012; 45:120-30. [PMID: 22075058 DOI: 10.1021/ar200154w] [Citation(s) in RCA: 73] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Since the pioneering work of Kai Siegbahn, electron spectroscopy for chemical analysis (ESCA) has been developed into an indispensable analytical technique for surface science. The value of this powerful method of photoelectron spectroscopy (PES, also termed photoemission spectroscopy) and Siegbahn's contributions were recognized in the 1981 Nobel Prize in Physics. The need for high vacuum, however, originally prohibited PES of volatile liquids, and only allowed for investigation of low-vapor-pressure molecules attached to a surface (or close to a surface) or liquid films of low volatility. Only with the invention of liquid beams of volatile liquids compatible with high-vacuum conditions was PES from liquid surfaces under vacuum made feasible. Because of the ubiquity of water interfaces in nature, the liquid water-vacuum interface became a most attractive research topic, particularly over the past 10 years. PES studies of these important aqueous interfaces remained significantly challenging because of the need to develop high-pressure PES methods. For decades, ESCA or PES (termed XPS, for X-ray photoelectron spectroscopy, in the case of soft X-ray photons) was restricted to conventional laboratory X-ray sources or beamlines in synchrotron facilities. This approach enabled frequency domain measurements, but with poor time resolution. Indirect access to time-resolved processes in the condensed phase was only achieved if line-widths could be analyzed or if processes could be related to a fast clock, that is, reference processes that are fast enough and are also well understood in the condensed phase. Just recently, the emergence of high harmonic light sources, providing short-wavelength radiation in ultrashort light pulses, added the dimension of time to the classical ESCA or XPS technique and opened the door to (soft) X-ray photoelectron spectroscopy with ultrahigh time resolution. The combination of high harmonic light sources (providing radiation with laserlike beam qualities) and liquid microjet technology recently enabled the first liquid interface PES experiments in the IR/UV-pump and extreme ultraviolet-probe (EUV-probe) configuration. In this Account, we highlight features of the technology and a number of recent applications, including extreme states of matter and the discovery and detection of short-lived transients of the solvated electron in water. Properties of the EUV radiation, such as its controllable polarization and features of the liquid microjet, will enable unique experiments in the near future. PES measures electron binding energies and angular distributions of photoelectrons, which comprise unique information about electron orbitals and their involvement in chemical bonding. One of the future goals is to use this information to trace molecular orbitals, over time, in chemical reactions or biological transformations.
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Affiliation(s)
- M. Faubel
- Max-Planck-Institut für Dynamik und Selbstorganisation, Bunsenstrasse 10, D-37073 Göttingen, Germany
| | - K. R. Siefermann
- Lawrence Berkeley National Laboratory, 1 Cyclotron Road 2-306, Berkeley, California 94720, United States
| | - Y. Liu
- Wilhelm-Ostwald-Institute for Physical and Theoretical Chemistry, University Leipzig, Linnéstrasse 2, D-04103 Leipzig, Germany
| | - B. Abel
- Wilhelm-Ostwald-Institute for Physical and Theoretical Chemistry, University Leipzig, Linnéstrasse 2, D-04103 Leipzig, Germany
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35
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Evans NL, Yu H, Roberts GM, Stavros VG, Ullrich S. Observation of ultrafast NH3 (Ã) state relaxation dynamics using a combination of time-resolved photoelectron spectroscopy and photoproduct detection. Phys Chem Chem Phys 2012; 14:10401-9. [DOI: 10.1039/c2cp40178a] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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36
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Wörner HJ, Bertrand JB, Fabre B, Higuet J, Ruf H, Dubrouil A, Patchkovskii S, Spanner M, Mairesse Y, Blanchet V, Mével E, Constant E, Corkum PB, Villeneuve DM. Conical Intersection Dynamics in NO
2
Probed by Homodyne High-Harmonic Spectroscopy. Science 2011; 334:208-12. [DOI: 10.1126/science.1208664] [Citation(s) in RCA: 201] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Affiliation(s)
- H. J. Wörner
- Joint Laboratory for Attosecond Science, National Research Council of Canada and University of Ottawa, 100 Sussex Drive, Ottawa, Ontario, Canada K1A 0R6
- Laboratorium für Physikalische Chemie, Eidgenössische Technische Hochschule Zürich, Wolfgang-Pauli-Strasse 10, 8093 Zürich, Switzerland
| | - J. B. Bertrand
- Joint Laboratory for Attosecond Science, National Research Council of Canada and University of Ottawa, 100 Sussex Drive, Ottawa, Ontario, Canada K1A 0R6
| | - B. Fabre
- Centre Lasers Intenses et Applications, Université de Bordeaux, CEA, CNRS, UMR5107, 351 Cours de la Libération, 33405 Talence, France
| | - J. Higuet
- Centre Lasers Intenses et Applications, Université de Bordeaux, CEA, CNRS, UMR5107, 351 Cours de la Libération, 33405 Talence, France
| | - H. Ruf
- Centre Lasers Intenses et Applications, Université de Bordeaux, CEA, CNRS, UMR5107, 351 Cours de la Libération, 33405 Talence, France
| | - A. Dubrouil
- Centre Lasers Intenses et Applications, Université de Bordeaux, CEA, CNRS, UMR5107, 351 Cours de la Libération, 33405 Talence, France
| | - S. Patchkovskii
- Joint Laboratory for Attosecond Science, National Research Council of Canada and University of Ottawa, 100 Sussex Drive, Ottawa, Ontario, Canada K1A 0R6
| | - M. Spanner
- Joint Laboratory for Attosecond Science, National Research Council of Canada and University of Ottawa, 100 Sussex Drive, Ottawa, Ontario, Canada K1A 0R6
| | - Y. Mairesse
- Centre Lasers Intenses et Applications, Université de Bordeaux, CEA, CNRS, UMR5107, 351 Cours de la Libération, 33405 Talence, France
| | - V. Blanchet
- Laboratoire Collisions Agrégats Réactivité (IRSAMC), UPS, Université de Toulouse, F-31062 Toulouse, France and CNRS, UMR 5589, F-31062 Toulouse, France
| | - E. Mével
- Centre Lasers Intenses et Applications, Université de Bordeaux, CEA, CNRS, UMR5107, 351 Cours de la Libération, 33405 Talence, France
| | - E. Constant
- Centre Lasers Intenses et Applications, Université de Bordeaux, CEA, CNRS, UMR5107, 351 Cours de la Libération, 33405 Talence, France
| | - P. B. Corkum
- Joint Laboratory for Attosecond Science, National Research Council of Canada and University of Ottawa, 100 Sussex Drive, Ottawa, Ontario, Canada K1A 0R6
| | - D. M. Villeneuve
- Joint Laboratory for Attosecond Science, National Research Council of Canada and University of Ottawa, 100 Sussex Drive, Ottawa, Ontario, Canada K1A 0R6
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37
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Wernet P, Gaudin J, Godehusen K, Schwarzkopf O, Eberhardt W. Femtosecond time-resolved photoelectron spectroscopy with a vacuum-ultraviolet photon source based on laser high-order harmonic generation. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2011; 82:063114. [PMID: 21721681 DOI: 10.1063/1.3600901] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
A laser-based tabletop approach to femtosecond time-resolved photoelectron spectroscopy with photons in the vacuum-ultraviolet (VUV) energy range is described. The femtosecond VUV pulses are produced by high-order harmonic generation (HHG) of an amplified femtosecond Ti:sapphire laser system. Two generations of the same setup and results from photoelectron spectroscopy in the gas phase are discussed. In both generations, a toroidal grating monochromator was used to select one harmonic in the photon energy range of 20-30 eV. The first generation of the setup was used to perform photoelectron spectroscopy in the gas phase to determine the bandwidth of the source. We find that our HHG source has a bandwidth of 140 ± 40 meV. The second and current generation is optimized for femtosecond pump-probe photoelectron spectroscopy with high flux and a small spot size at the sample of the femtosecond probe pulses. The VUV radiation is focused into the interaction region with a toroidal mirror to a spot smaller than 100 × 100 μm(2) and the flux amounts to 10(10) photons/s at the sample at a repetition rate of 1 kHz. The duration of the monochromatized VUV pulses is determined to be 120 fs resulting in an overall pump-probe time resolution of 135 ± 5 fs. We show how this setup can be used to map the transient valence electronic structure in molecular dissociation.
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Affiliation(s)
- Philippe Wernet
- Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Albert-Einstein-Strasse 15, 12489 Berlin, Germany.
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38
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Fushitani M, Matsuda A, Hishikawa A. Time-resolved EUV photoelectron spectroscopy of dissociating I2 by laser harmonics at 80 nm. OPTICS EXPRESS 2011; 19:9600-9606. [PMID: 21643218 DOI: 10.1364/oe.19.009600] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Generation of single-order laser harmonics in extreme ultraviolet (EUV) and the application to the time-resolved photoelectron spectroscopy of I(2) are demonstrated. The EUV pulses at 80 nm were generated from Kr as the 5th order harmonics of intense 400 nm laser pulses and then separated from other harmonic orders by a thin indium foil. The pump-probe photoelectron spectroscopy of I(2) in the B (3)Π(0(u)(+)) and B" (1)Π(1(u)) states excited by visible laser pulses at 490 nm showed a rapid increase in the yield of atomic iodine (~400 fs), reflecting the dissociation dynamics evolving simultaneously in the two excited states.
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Affiliation(s)
- Mizuho Fushitani
- Department of Chemistry, Graduate School of Science, Nagoya University, Nagoya, Aichi 464-8602, Japan
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39
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Dachraoui H, Michelswirth M, Siffalovic P, Bartz P, Schäfer C, Schnatwinkel B, Mattay J, Pfeiffer W, Drescher M, Heinzmann U. Photoinduced reconfiguration cycle in a molecular adsorbate layer studied by femtosecond inner-shell photoelectron spectroscopy. PHYSICAL REVIEW LETTERS 2011; 106:107401. [PMID: 21469832 DOI: 10.1103/physrevlett.106.107401] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/24/2010] [Indexed: 05/30/2023]
Abstract
A time-resolved study of core-level chemical shifts in a monolayer of aromatic molecules reveals complex photoinduced reaction dynamics. The combination of electron spectroscopy for chemical analysis and ultrashort pulse excitation in the extreme ultraviolet allows performing time-correlated 4d-core-level spectroscopy of iodine atoms that probe the local chemical environment in the adsorbate molecule. The selectivity of the method unveils metastable molecular configurations that appear about 50 ps after the excitation and are efficiently quenched back to the ground state.
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Affiliation(s)
- H Dachraoui
- Molekül und Oberflächenphysik, Fakultät für Physik, Universität Bielefeld, Universitätsstraße 25, 33615 Bielefeld, Germany
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40
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Lecointre J, Roberts GM, Horke DA, Verlet JRR. Ultrafast relaxation dynamics observed through time-resolved photoelectron angular distributions. J Phys Chem A 2011; 114:11216-24. [PMID: 20961158 DOI: 10.1021/jp1028855] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Time-resolved photoelectron imaging of the 7,7,8,8-tetracyanoquinodimethane (TCNQ) radical anion is presented. Photoelectron angular distributions (PADs) are qualitatively analyzed in terms of the simple s-p model that is based on symmetry arguments. The internal conversion dynamics from the first excited state (1(2)B(3u)) to the ground state ((2)B(2g)) may be observed through temporal changes in the PADs of the spectrally overlapping photoelectron features arising from photodetachment of the ground state and the excited state. A formulism for extracting the population dynamics from the β(2) anisotropy parameter of overlapping spectroscopic features is presented. This is used to extract the lifetime of the first excited state, which is in good agreement with that observed in the time-resolved photoelectron spectra.
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Affiliation(s)
- Julien Lecointre
- Department of Chemistry, University of Durham, South Road, Durham, DH1 3LE, UK
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41
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Krikunova M, Maltezopoulos T, Wessels P, Schlie M, Azima A, Wieland M, Drescher M. Ultrafast photofragmentation dynamics of molecular iodine driven with timed XUV and near-infrared light pulses. J Chem Phys 2011; 134:024313. [DOI: 10.1063/1.3528722] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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42
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Plenge J, Wirsing A, Raschpichler C, Wassermann B, Rühl E. Control of coherent excitation of neon in the extreme ultraviolet regime. Faraday Discuss 2011; 153:361-73; discussion 395-413. [PMID: 22452090 DOI: 10.1039/c1fd00032b] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Coherent excitation of a superposition of Rydberg states in neon by the 13th harmonic of an intense 804 nm pulse and the formation of a wave packet is reported. Pump-probe experiments are performed, where the 3d-manifold of the 2p6-->2p5 (2P3/2) 3d [1/2]1- and 2p6-->2p5 (2P3/2) 3d [3/2]1-transitions are excited by an extreme ultraviolet (XUV) radiation pulse, which is centered at 20.05 eV photon energy. The temporal evolution of the excited state population is probed by ionization with a time-delayed 804 nm pulse. Control of coherent transient excitation and wave packet dynamics in the XUV-regime is demonstrated, where the spectral phase of the 13th harmonic is used as a control parameter. Modulation of the phase is achieved by propagation of the XUV-pulse through neon of variable gas density. The experimental results indicate that phase-shaped high-order harmonics can be used to control fundamental coherent excitation processes in the XUV-regime.
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Affiliation(s)
- Jürgen Plenge
- Physikalische und Theoretische Chemie, Institut für Chemie und Biochemie, Freie Universität Berlin, Takustr. 3, 14195 Berlin, Germany.
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43
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Wernet P. Electronic structure in real time: mapping valence electron rearrangements during chemical reactions. Phys Chem Chem Phys 2011; 13:16941-54. [DOI: 10.1039/c0cp02934c] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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44
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Filsinger F, Meijer G, Stapelfeldt H, Chapman HN, Küpper J. State- and conformer-selected beams of aligned and oriented molecules for ultrafast diffraction studies. Phys Chem Chem Phys 2010; 13:2076-87. [PMID: 21165481 DOI: 10.1039/c0cp01585g] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The manipulation of the motion of neutral molecules with electric or magnetic fields has seen tremendous progress over the last decade. Recently, these techniques have been extended to the manipulation of large and complex molecules. In this article we introduce experimental approaches to the manipulation of large molecules, i.e., the deflection, focusing and deceleration using electric fields. We detail how these methods can be exploited to spatially separate quantum states and how to select individual conformers of complex molecules. We briefly describe mixed-field orientation experiments made possible by the quantum-state selection. Moreover, we provide an outlook on ultrafast diffraction experiments using these highly controlled samples.
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Affiliation(s)
- Frank Filsinger
- Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, 14195 Berlin, Germany
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45
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Following a chemical reaction using high-harmonic interferometry. Nature 2010; 466:604-7. [PMID: 20671706 DOI: 10.1038/nature09185] [Citation(s) in RCA: 152] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2009] [Accepted: 05/20/2010] [Indexed: 11/08/2022]
Abstract
The study of chemical reactions on the molecular (femtosecond) timescale typically uses pump laser pulses to excite molecules and subsequent probe pulses to interrogate them. The ultrashort pump pulse can excite only a small fraction of molecules, and the probe wavelength must be carefully chosen to discriminate between excited and unexcited molecules. The past decade has seen the emergence of new methods that are also aimed at imaging chemical reactions as they occur, based on X-ray diffraction, electron diffraction or laser-induced recollision--with spectral selection not available for any of these new methods. Here we show that in the case of high-harmonic spectroscopy based on recollision, this apparent limitation becomes a major advantage owing to the coherent nature of the attosecond high-harmonic pulse generation. The coherence allows the unexcited molecules to act as local oscillators against which the dynamics are observed, so a transient grating technique can be used to reconstruct the amplitude and phase of emission from the excited molecules. We then extract structural information from the amplitude, which encodes the internuclear separation, by quantum interference at short times and by scattering of the recollision electron at longer times. The phase records the attosecond dynamics of the electrons, giving access to the evolving ionization potentials and the electronic structure of the transient molecule. In our experiment, we are able to document a temporal shift of the high-harmonic field of less than an attosecond (1 as = 10(-18) s) between the stretched and compressed geometry of weakly vibrationally excited Br(2) in the electronic ground state. The ability to probe structural and electronic features, combined with high time resolution, make high-harmonic spectroscopy ideally suited to measuring coupled electronic and nuclear dynamics occurring in photochemical reactions and to characterizing the electronic structure of transition states.
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46
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Wörner HJ, Bertrand JB, Corkum PB, Villeneuve DM. High-harmonic homodyne detection of the ultrafast dissociation of Br2 molecules. PHYSICAL REVIEW LETTERS 2010; 105:103002. [PMID: 20867516 DOI: 10.1103/physrevlett.105.103002] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/29/2010] [Indexed: 05/29/2023]
Abstract
We report the time-resolved observation of the photodissociation of Br2 using high-harmonic generation (HHG) as a probe. The simultaneous measurement of the high-harmonic and ion yields shows that high harmonics generated by the electronically excited state interfere with harmonics generated by the ground state. The resulting homodyne effect provides a high sensitivity to the excited state dynamics. We present a simple theoretical model that accounts for the main observations. Our experiment paves the way towards the dynamic imaging of molecules using HHG.
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Affiliation(s)
- H J Wörner
- Joint Laboratory for Attosecond Science, National Research Council of Canada and University of Ottawa, 100 Sussex Drive, Ottawa, Ontario, Canada K1A 0R6
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47
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Kornilov O, Wilcox R, Gessner O. Nanograting-based compact vacuum ultraviolet spectrometer and beam profiler for in situ characterization of high-order harmonic generation light sources. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2010; 81:063109. [PMID: 20590227 DOI: 10.1063/1.3443575] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
A compact, versatile device for vacuum ultraviolet (VUV) beam characterization is presented. It combines the functionalities of a VUV spectrometer and a VUV beam profiler in one unit and is entirely supported by a standard DN200 CF flange. The spectrometer employs a silicon nitride transmission nanograting in combination with a microchannel plate-based imaging detector. This enables the simultaneous recording of wavelengths ranging from 10 to 80 nm with a resolution of 0.25-0.13 nm. Spatial beam profiles with diameters up to 10 mm are imaged with 0.1 mm resolution. The setup is equipped with an in-vacuum translation stage that allows for in situ switching between the spectrometer and beam profiler modes and for moving the setup out of the beam. The simple, robust design of the device is well suited for nonintrusive routine characterization of emerging laboratory- and accelerator-based VUV light sources. Operation of the device is demonstrated by characterizing the output of a femtosecond high-order harmonic generation light source.
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Affiliation(s)
- Oleg Kornilov
- Ultrafast X-Ray Science Laboratory, Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
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48
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Ito M, Kataoka Y, Okamoto T, Yamashita M, Sekikawa T. Spatiotemporal characterization of single-order high harmonic pulses from time-compensated toroidal-grating monochromator. OPTICS EXPRESS 2010; 18:6071-8. [PMID: 20389628 DOI: 10.1364/oe.18.006071] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Extreme ultraviolet (XUV) single-order high harmonic pulses with 10(6) photons/pulse were separated from multiple harmonic orders by a time-compensated toroidal-grating monochromator consisting of a pair of toroidal gratings. The first grating separates the harmonic order and the second one compensates for the pulse-front tilt. The center photon energies were tunable between 42 and 23 eV. The separated single harmonic pulses were spatially and temporally characterized as having a spot size of 58 +/- 3 microm at the focus, with a shortest pulse duration of 47 +/- 2 fs. The developed XUV light source is versatile for application to time- and space-resolved spectroscopy.
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Affiliation(s)
- Motohiko Ito
- Department of Applied Physics, Hokkaido University, Kita-13, Nishi-8, Kita-ku, Sapporo 060-8628, Japan
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49
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Kornilov O, Wang CC, Bünermann O, Healy AT, Leonard M, Peng C, Leone SR, Neumark DM, Gessner O. Ultrafast Dynamics in Helium Nanodroplets Probed by Femtosecond Time-Resolved EUV Photoelectron Imaging. J Phys Chem A 2009; 114:1437-45. [DOI: 10.1021/jp907312t] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Oleg Kornilov
- Ultrafast X-ray Science Laboratory, Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, and Department of Chemistry, University of California, Berkeley, California 94720
| | - Chia C. Wang
- Ultrafast X-ray Science Laboratory, Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, and Department of Chemistry, University of California, Berkeley, California 94720
| | - Oliver Bünermann
- Ultrafast X-ray Science Laboratory, Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, and Department of Chemistry, University of California, Berkeley, California 94720
| | - Andrew T. Healy
- Ultrafast X-ray Science Laboratory, Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, and Department of Chemistry, University of California, Berkeley, California 94720
| | - Mathew Leonard
- Ultrafast X-ray Science Laboratory, Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, and Department of Chemistry, University of California, Berkeley, California 94720
| | - Chunte Peng
- Ultrafast X-ray Science Laboratory, Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, and Department of Chemistry, University of California, Berkeley, California 94720
| | - Stephen R. Leone
- Ultrafast X-ray Science Laboratory, Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, and Department of Chemistry, University of California, Berkeley, California 94720
| | - Daniel M. Neumark
- Ultrafast X-ray Science Laboratory, Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, and Department of Chemistry, University of California, Berkeley, California 94720
| | - Oliver Gessner
- Ultrafast X-ray Science Laboratory, Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, and Department of Chemistry, University of California, Berkeley, California 94720
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Abstract
Abstract
Electron spectroscopy for chemical analysis (ESCA) is a well established tool for quantitative studies of the composition and the chemical environment of molecular systems. Recent developments in the generation and utilization of ultrashort X-ray pulses now add the dimension of time to this technique and will expand the possibilities of femtochemistry in terms of chemical selectivity, quality of information, and temporal resolution. The properties and capabilities of various X-ray pulse sources are discussed, along with their prospects for dynamical studies. Examples of time-resolved electron spectroscopy are presented in the femtosecond (1 fs = 10−15 s) as well as the attosecond (1 as = 10−18 s) regime, the latter marking the current ultimate limit for the time-resolution in pump-probe experiments.
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