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Robinson MS, Küpper J. Unraveling the ultrafast dynamics of thermal-energy chemical reactions. Phys Chem Chem Phys 2024; 26:1587-1601. [PMID: 38131437 DOI: 10.1039/d3cp03954d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2023]
Abstract
In this perspective, we discuss how one can initiate, image, and disentangle the ultrafast elementary steps of thermal-energy chemical dynamics, building upon advances in technology and scientific insight. We propose that combinations of ultrashort mid-infrared laser pulses, controlled molecular species in the gas phase, and forefront imaging techniques allow to unravel the elementary steps of general-chemistry reaction processes in real time. We detail, for prototypical first reaction systems, experimental methods enabling these investigations, how to sufficiently prepare and promote gas-phase samples to thermal-energy reactive states with contemporary ultrashort mid-infrared laser systems, and how to image the initiated ultrafast chemical dynamics. The results of such experiments will clearly further our understanding of general-chemistry reaction dynamics.
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Affiliation(s)
- Matthew S Robinson
- Center for Free-Electron Laser Science CFEL, Deutsches Elektronen-Synchrotron DESY, Notkestr. 85, 22607 Hamburg, Germany.
- Center for Ultrafast Imaging, Universität Hamburg, Luruper Chaussee 149, 22761 Hamburg, Germany
| | - Jochen Küpper
- Center for Free-Electron Laser Science CFEL, Deutsches Elektronen-Synchrotron DESY, Notkestr. 85, 22607 Hamburg, Germany.
- Center for Ultrafast Imaging, Universität Hamburg, Luruper Chaussee 149, 22761 Hamburg, Germany
- Department of Physics, Universität Hamburg, Luruper Chaussee 149, 22761 Hamburg, Germany
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Abstract
Direct experimental determination of precise electron affinities (EAs) of lanthanides is a longstanding challenge to experimentalists. Considerable debate exists in previous experiment and theory, hindering the complete understanding about the properties of the atomic anions. Herein, we report the first precise photoelectron imaging spectroscopy of europium (Eu), with the aim of eliminating prior contradictions. The measured EA (0.116 ± 0.013 eV) of Eu is in excellent agreement with recently reported theoretical predictions, providing direct spectroscopic evidence that the additional electron is weakly attached. Additionally, a new experimental strategy is proposed that can significantly increase the yield of the lanthanide anions, opening up the best opportunity to complete the periodic table of the atomic anions. The present findings not only serve to resolve previous discrepancy but also will help in improving the depth and accuracy of our understanding about the fundamental properties of the atomic anions.
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Das S, Pal S, Krishnamurty S. Understanding the Site Selectivity in Small-Sized Neutral and Charged Aln (4 ≤ n ≤ 7) Clusters Using Density Functional Theory Based Reactivity Descriptors: A Validation Study on Water Molecule Adsorption. J Phys Chem A 2013; 117:8691-702. [DOI: 10.1021/jp403109s] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Susanta Das
- Physical Chemistry Division, CSIR-National Chemical Laboratory, Pune 411008, India
| | - Sourav Pal
- Physical Chemistry Division, CSIR-National Chemical Laboratory, Pune 411008, India
| | - Sailaja Krishnamurty
- Functional Materials Division, CSIR-Central Electrochemical Research Institute, Karaikudi 630006,
India
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Goebbert DJ, Sanov A. Photodetachment, photofragmentation, and fragment autodetachment of [O[sub 2n](H[sub 2]O)[sub m]][sup −] clusters: Core-anion structures and fragment energy partitioning. J Chem Phys 2009. [DOI: 10.1063/1.3224135] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Kang C, Troyer JL, Robertson EM, Rothgeb DW, Hossain E, Wyrwas RB, Parmenter CS, Jarrold CC. Solvation of O(2)(-) and O(4)(-) by p-difluorobenzene and p-xylene studied by photoelectron spectroscopy. J Chem Phys 2008; 128:104309. [PMID: 18345890 DOI: 10.1063/1.2838849] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Anion photoelectron spectra of the O(2)(-) . arene and O(4)(-) . arene complexes with p-xylene and p-difluorobenzene are presented and analyzed with the aid of calculations on the anions and corresponding neutrals. Relative to the adiabatic electron affinity of O(2), the O(2)(-) . arene spectra are blueshifted by 0.75-1 eV. Solvation energy alone does not account for this shift, and it is proposed that a repulsive portion of the neutral potential energy surface is accessed in the detachment, resulting in dissociative photodetachment. O(2)(-) is found to interact more strongly with the p-difluorobenzene than the p-xylene. The binding motif involves the O(2)(-) in plane with the arene, interacting via electron donation along nearby C-H bonds. A peak found at 4.36(2) eV in the photoelectron spectrum of O(2)(-) . p-difluorobenzene (p-DFB) is tentatively attributed to the charge transfer state, O(2)(-) . p-DFB(+). Spectra of O(4)(-) . arene complexes show less blueshift in electron binding energy relative to the spectrum of bare O(4)(-), which itself undergoes dissociative photodetachment. The striking similarity between the profiles of the O(4)(-) . arene complexes with the O(4)(-) spectrum suggests that the O(4)(-) molecule remains intact upon complex formation, and delocalization of the charge across the O(4)(-) molecule results in similar structures for the anion and neutral complexes.
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Affiliation(s)
- Cheolhwa Kang
- Department of Chemistry, Indiana University, Bloomington, IN 47405, USA
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Antonchenko VY, Kryachko ES. Structural, energetic, and spectroscopic features of lower energy complexes of superoxide hydrates O2(-)(H2O)(1-4). J Phys Chem A 2007; 109:3052-9. [PMID: 16833629 DOI: 10.1021/jp046498z] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
The lower-energy portions of the potential energy surfaces of superoxide hydrates O2(-)(H2O)(1< or = n < or = 4) are thoroughly investigated at high computational levels. The structural, energetic and spectroscopic features of the stable superoxide hydrates on these potential energy surfaces are discussed, focusing in particular on some implications to their infrared spectra and the hydrogen bond trends. The present work reports the transition-state linkers between the most stable superoxide hydrates which are useful to understand the energetics of their mutual interconversions.
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Paik DH, Baskin JS, Kim NJ, Zewail AH. Ultrafast vectorial and scalar dynamics of ionic clusters: Azobenzene solvated by oxygen. J Chem Phys 2006; 125:133408. [PMID: 17029482 DOI: 10.1063/1.2205855] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The ultrafast dynamics of clusters of trans-azobenzene anion (A-) solvated by oxygen molecules was investigated using femtosecond time-resolved photoelectron spectroscopy. The time scale for stripping off all oxygen molecules from A- was determined by monitoring in real time the transient of the A- rise, following an 800 nm excitation of A- (O2)n, where n = 1-4. A careful analysis of the time-dependent photoelectron spectra strongly suggests that for n > 1 a quasi-O4 core is formed and that the dissociation occurs by a bond cleavage between A- and conglomerated (O2)n rather than a stepwise evaporation of O2. With time and energy resolutions, we were able to capture the photoelectron signatures of transient species which instantaneously rise (<100 fs) then decay. The transient species are assigned as charge-transfer complexes: A.O2- for A- O2 and A.O4-(O2)n-2 for A-(O2)n, where n = 2-4. Subsequent to an ultrafast electron recombination, A- rises with two distinct time scales: a subpicosecond component reflecting a direct bond rupture of the A- -(O2)n nuclear coordinate and a slower component (1.6-36 ps, increasing with n) attributed to an indirect channel exhibiting a quasistatistical behavior. The photodetachment transients exhibit a change in the transition dipole direction as a function of time delay. Rotational dephasing occurs on a time scale of 2-3 ps, with a change in the sign of the transient anisotropy between A- O2 and the larger clusters. This behavior is a key indicator of an evolving cluster structure and is successfully modeled by calculations based on the structures and inertial motion of the parent clusters.
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Affiliation(s)
- D Hern Paik
- Laboratory for Molecular Sciences, California Institute of Technology, Pasadena, California 91125, USA
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Cheng PY, Baskin JS, Zewail AH. Dynamics of clusters: from elementary to biological structures. Proc Natl Acad Sci U S A 2006; 103:10570-6. [PMID: 16740669 PMCID: PMC1502273 DOI: 10.1073/pnas.0507114103] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Between isolated atoms or molecules and bulk materials there lies a class of unique structures, known as clusters, that consist of a few to hundreds of atoms or molecules. Within this range of "nanophase," many physical and chemical properties of the materials evolve as a function of cluster size, and materials may exhibit novel properties due to quantum confinement effects. Understanding these phenomena is in its own rights fundamental, but clusters have the additional advantage of being controllable model systems for unraveling the complexity of condensed-phase and biological structures, not to mention their vanguard role in defining nanoscience and nanotechnology. Over the last two decades, much progress has been made, and this short overview highlights our own involvement in developing cluster dynamics, from the first experiments on elementary systems to model systems in the condensed phase, and on to biological structures.
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Affiliation(s)
| | - J. Spencer Baskin
- Laboratory for Molecular Sciences, Arthur Amos Noyes Laboratory of Chemical Physics, California Institute of Technology, Pasadena, CA 91125
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Muntean F, Taylor MS, McCoy AB, Lineberger WC. Femtosecond study of Cu(H2O) dynamics. J Chem Phys 2004; 121:5676-87. [PMID: 15366991 DOI: 10.1063/1.1782176] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
The short-time nuclear dynamics of Cu(H(2)O) is investigated using femtosecond photodetachment-photoionization spectroscopy and time-dependent quantum wave packet calculations. The Cu(H(2)O) dynamics is initiated in the electronic ground state of the complex by electron photodetachment from the Cu(-)(H(2)O) complex, where hydrogen atoms are oriented toward Cu. Several time-resolved resonant multiphoton ionization schemes are used to probe the ensuing reorientation and dissociation. Immediately following photodetachment, the neutral complex is far from its minimum energy geometry and possesses an internal energy comparable to the Cu-H(2)O dissociation energy and undergoes both large-amplitude H(2)O motion and dissociation. Dissociation is observed to occur on three distinct time scales: 0.6, 8, and 100 ps. These results are compared to the results of time-dependent J=0 wave packet calculations, propagating the initial anion vibrational wave functions on the ground-state potential of the neutral complex. An excellent agreement is obtained between the experimental results and the ionization signals derived from the calculated probability amplitudes. Related experiments and calculations are carried out on the Cu(D(2)O) complex, with results very similar to those of Cu(H(2)O).
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Affiliation(s)
- Felician Muntean
- JILA, Department of Chemistry and Biochemistry, University of Colorado, Boulder, Colorado 80309, USA
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Affiliation(s)
- Albert Stolow
- Steacie Institute for Molecular Sciences, National Research Council of Canada, 100 Sussex Drive, Ottawa, Ontario, K1A 0R6 Canada.
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Affiliation(s)
- T E Dermota
- Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802, USA
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Kim NJ, Paik DH, Zewail AH. Femtosecond dynamics of solvated oxygen anions. II. Nature of dissociation and caging in finite-sized clusters. J Chem Phys 2003. [DOI: 10.1063/1.1561434] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Paik DH, Kim NJ, Zewail AH. Femtosecond dynamics of solvated oxygen anions. I. Bifurcated electron transfer dynamics probed by photoelectron spectroscopy. J Chem Phys 2003. [DOI: 10.1063/1.1561433] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Kelley JA, Robertson WH, Johnson MA. Observation of sharp vibronic bands in the O4− `core ion' by mid infrared predissociation spectroscopy of O4−·Ar clusters. Chem Phys Lett 2002. [DOI: 10.1016/s0009-2614(02)01017-5] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Clements TG, Continetti RE. Four-body reaction dynamics: complete correlated fragment measurement of the dissociative photodetachment dynamics of O(-)(8). PHYSICAL REVIEW LETTERS 2002; 89:033005. [PMID: 12144391 DOI: 10.1103/physrevlett.89.033005] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/05/2002] [Indexed: 05/23/2023]
Abstract
The four-body dissociative photodetachment (DPD) dynamics of O-8 were studied using photoelectron photofragment coincidence (PPC) spectroscopy. All four neutral photofragments were measured in coincidence with the photodetached electron, yielding a five-body kinematically complete experiment. Velocity and angular correlations for DPD of O(-)(8) are presented and compared to those for O(-)(6). The DPD dynamics and energetics of O(-)(8).are found to be similar to those of O-4 and O-6 implying that the additional solvating O(2) molecules act essentially as spectators, but exhibit inequivalent kinematic behavior implying asymmetric solvation.
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Affiliation(s)
- Todd G Clements
- Department of Chemistry and Biochemistry, University of California-San Diego, 9500 Gilman Drive, La Jolla, California 92093-0340, USA
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Bibliography. Current literature in mass spectrometry. JOURNAL OF MASS SPECTROMETRY : JMS 2001; 36:1241-1248. [PMID: 11747122 DOI: 10.1002/jms.98] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
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