1
|
Wang Y, Zhao Y, Luo C, Zhang N, Wang W, Hu L, Yuan D, Wang X. High-Resolution Imaging Study on Photodissociation of OCS + [A 2Π Ω=1/2,3/2 (ν 1 0 ν 3)]. J Phys Chem A 2024; 128:4765-4774. [PMID: 38840312 DOI: 10.1021/acs.jpca.4c01358] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/07/2024]
Abstract
The development of the velocity map ion imaging (VMI) technique has greatly advanced the study of photodissociation dynamics. The high-resolution imaging study of the photodissociation allows for the acquisition of precise and detailed information on the fragments. This information can further provide more insight into the energy partition and potential pathways involved in the photodissociation process. In this study, we report the investigation on the photodissociation of OCS+ via the A2ΠΩ=1/2,3/2 states following the excitation of A2Π (ν1 0 ν3) ← X2Π (0 0 0) by using time-sliced VMI techniques in the ultraviolet region. Our investigation revealed significant mode-dependent recoil anisotropies and branching ratios of two product channels for both Ω = 1/2 and Ω = 3/2. The photolysis products also exhibited dramatic deviation in angular distributions and generally comparable kinetic energy distributions following the excitation to the same vibrational modes of A2ΠΩ states with two separate spin-orbit components. According to the observation in this study and previously reported photodissociation mechanisms of the OCS+ cations, the decay from the A2Π3/2 state was more likely via the internal conversion to high rovibrational states of the X2Π state, in comparison to the A2Π1/2 state.
Collapse
Affiliation(s)
- Yaling Wang
- Hefei National Research Center for Physical Science at Microscale and Department of Chemical Physics, University of Science and Technology of China, Hefei 230026, China
| | - Yunfan Zhao
- Hefei National Research Center for Physical Science at Microscale and Department of Chemical Physics, University of Science and Technology of China, Hefei 230026, China
| | - Chang Luo
- Hefei National Research Center for Physical Science at Microscale and Department of Chemical Physics, University of Science and Technology of China, Hefei 230026, China
| | - Ning Zhang
- Hefei National Research Center for Physical Science at Microscale and Department of Chemical Physics, University of Science and Technology of China, Hefei 230026, China
| | - Wenxin Wang
- Hefei National Research Center for Physical Science at Microscale and Department of Chemical Physics, University of Science and Technology of China, Hefei 230026, China
| | - Liru Hu
- Hefei National Research Center for Physical Science at Microscale and Department of Chemical Physics, University of Science and Technology of China, Hefei 230026, China
| | - Daofu Yuan
- Hefei National Research Center for Physical Science at Microscale and Department of Chemical Physics, University of Science and Technology of China, Hefei 230026, China
| | - Xingan Wang
- Hefei National Research Center for Physical Science at Microscale and Department of Chemical Physics, University of Science and Technology of China, Hefei 230026, China
- Hefei National Laboratory, Hefei 230088, China
| |
Collapse
|
2
|
Tasi DA, Czakó G. Benchmark ab initio characterization of the complex potential energy surfaces of the HOO - + CH 3Y [Y = F, Cl, Br, I] reactions. Phys Chem Chem Phys 2024; 26:16048-16059. [PMID: 38779842 DOI: 10.1039/d4cp01071j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/25/2024]
Abstract
The α-effect is a well-known phenomenon in organic chemistry, and is related to the enhanced reactivity of nucleophiles involving one or more lone-pair electrons adjacent to the nucleophilic center. The gas-phase bimolecular nucleophilic substitution (SN2) reactions of α-nucleophile HOO- with methyl halides have been thoroughly investigated experimentally and theoretically; however, these investigations have mainly focused on identifying and characterizing the α-effect of HOO-. Here, we perform the first comprehensive high-level ab initio mapping for the HOO- + CH3Y [Y = F, Cl, Br and I] reactions utilizing the modern explicitly-correlated CCSD(T)-F12b method with the aug-cc-pVnZ [n = 2-4] basis sets. The present ab initio characterization considers five distinct product channels of SN2: (CH3OOH + Y-), proton abstraction (CH2Y- + H2O2), peroxide ion substitution (CH3OO- + HY), SN2-induced elimination (CH2O + HY + HO-) and SN2-induced rearrangement (CH2(OH)O- + HY). Moreover, besides the traditional back-side attack Walden inversion, the pathways of front-side attack, double inversion and halogen-bond complex formation have also been explored for SN2. With regard to the Walden inversion of HOO- + CH3Cl, the previously unaddressed discrepancies concerning the geometry of the corresponding transition state are clarified. For the HOO- + CH3F reaction, the recently identified SN2-induced elimination is found to be more exothermic than the SN2 channel, submerged by ∼36 kcal mol-1. The accuracy of our high-level ab initio calculations performed in the present study is validated by the fact that our new benchmark 0 K reaction enthalpies show excellent agreement with the experimental data in nearly all cases.
Collapse
Affiliation(s)
- Domonkos A Tasi
- MTA-SZTE Lendület Computational Reaction Dynamics Research Group, Interdisciplinary Excellence Centre and Department of Physical Chemistry and Materials Science, Institute of Chemistry, University of Szeged, Rerrich Béla tér 1, Szeged H-6720, Hungary.
| | - Gábor Czakó
- MTA-SZTE Lendület Computational Reaction Dynamics Research Group, Interdisciplinary Excellence Centre and Department of Physical Chemistry and Materials Science, Institute of Chemistry, University of Szeged, Rerrich Béla tér 1, Szeged H-6720, Hungary.
| |
Collapse
|
3
|
Schatz GC, Wodtke AM, Yang X. Spiers Memorial Lecture: New directions in molecular scattering. Faraday Discuss 2024. [PMID: 38764350 DOI: 10.1039/d4fd00015c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/21/2024]
Abstract
The field of molecular scattering is reviewed as it pertains to gas-gas as well as gas-surface chemical reaction dynamics. We emphasize the importance of collaboration of experiment and theory, from which new directions of research are being pursued on increasingly complex problems. We review both experimental and theoretical advances that provide the modern toolbox available to molecular-scattering studies. We distinguish between two classes of work. The first involves simple systems and uses experiment to validate theory so that from the validated theory, one may learn far more than could ever be measured in the laboratory. The second class involves problems of great complexity that would be difficult or impossible to understand without a partnership of experiment and theory. Key topics covered in this review include crossed-beams reactive scattering and scattering at extremely low energies, where quantum effects dominate. They also include scattering from surfaces, reactive scattering and kinetics at surfaces, and scattering work done at liquid surfaces. The review closes with thoughts on future promising directions of research.
Collapse
Affiliation(s)
- George C Schatz
- Dept of Chemistry, Northwestern University, Evanston, Illinois 60208, USA
| | - Alec M Wodtke
- Institute for Physical Chemistry, Georg August University, Goettingen, Germany
- Max Planck Institute for Multidisciplinary Natural Sciences, Goettingen, Germany.
- International Center for the Advanced Studies of Energy Conversion, Georg August University, Goettingen, Germany
| | - Xueming Yang
- Dalian Institute for Chemical Physics, Chinese Academy of Sciences, Dalian, China
- Department of Chemistry, College of Science, Southern University of Science and Technology, Shenzhen, China
| |
Collapse
|
4
|
Chang Y, Ashfold MNR, Yuan K, Yang X. Exploring the vacuum ultraviolet photochemistry of astrochemically important triatomic molecules. Natl Sci Rev 2023; 10:nwad158. [PMID: 37771464 PMCID: PMC10533343 DOI: 10.1093/nsr/nwad158] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2022] [Revised: 11/03/2022] [Accepted: 02/08/2023] [Indexed: 09/30/2023] Open
Abstract
The recently constructed vacuum ultraviolet (VUV) free electron laser (FEL) at the Dalian Coherent Light Source (DCLS) is yielding a wealth of new and exquisitely detailed information about the photofragmentation dynamics of many small gas-phase molecules. This Review focuses particular attention on five triatomic molecules-H2O, H2S, CO2, OCS and CS2. Each shows excitation wavelength-dependent dissociation dynamics, yielding photofragments that populate a range of electronic and (in the case of diatomic fragments) vibrational and rotational quantum states, which can be characterized by different translational spectroscopy methods. The photodissociation of an isolated molecule from a well-defined initial quantum state provides a lens through which one can investigate how and why chemical reactions occur, and provides numerous opportunities for fruitful, synergistic collaborations with high-level ab initio quantum chemists. The chosen molecules, their photofragments and the subsequent chemical reaction networks to which they can contribute are all crucial in planetary atmospheres and in interstellar and circumstellar environments. The aims of this Review are 3-fold: to highlight new photochemical insights enabled by the VUV-FEL at the DCLS, notably the recently recognized central atom elimination process that is shown to contribute in all of these triatomic molecules; to highlight some of the potential implications of this rich photochemistry to our understanding of interstellar chemistry and molecular evolution within the universe; and to highlight other and future research directions in areas related to chemical reaction dynamics and astrochemistry that will be enabled by increased access to VUV-FEL sources.
Collapse
Affiliation(s)
- Yao Chang
- State Key Laboratory of Molecular Reaction Dynamics and Dalian Coherent Light Source, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China
| | | | - Kaijun Yuan
- State Key Laboratory of Molecular Reaction Dynamics and Dalian Coherent Light Source, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China
- University of Chinese Academy of Sciences, Beijing 100049, China
- Hefei National Laboratory, Hefei 230088, China
| | - Xueming Yang
- State Key Laboratory of Molecular Reaction Dynamics and Dalian Coherent Light Source, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China
- Hefei National Laboratory, Hefei 230088, China
- Department of Chemistry, College of Science, Southern University of Science and Technology, Shenzhen 518055, China
| |
Collapse
|
5
|
Crane SW, Lee JWL, Ashfold MNR, Rolles D. Molecular photodissociation dynamics revealed by Coulomb explosion imaging. Phys Chem Chem Phys 2023. [PMID: 37335247 DOI: 10.1039/d3cp01740k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/21/2023]
Abstract
Coulomb explosion imaging (CEI) methods are finding ever-growing use as a means of exploring and distinguishing the static stereo-configurations of small quantum systems (molecules, clusters, etc). CEI experiments initiated by ultrafast (femtosecond-duration) laser pulses also allow opportunities to track the time-evolution of molecular structures, and thereby advance understanding of molecular fragmentation processes. This Perspective illustrates two emerging families of dynamical studies. 'One-colour' studies (employing strong field ionisation driven by intense near infrared or single X-ray or extreme ultraviolet laser pulses) afford routes to preparing multiply charged molecular cations and exploring how their fragmentation progresses from valence-dominated to Coulomb-dominated dynamics with increasing charge and how this evolution varies with molecular size and composition. 'Two-colour' studies use one ultrashort laser pulse to create electronically excited neutral molecules (or monocations), whose structural evolution is then probed as a function of pump-probe delay using an ultrafast ionisation pulse along with time and position-sensitive detection methods. This latter type of experiment has the potential to return new insights into not just molecular fragmentation processes but also charge transfer processes between moieties separating with much better defined stereochemical control than in contemporary ion-atom and ion-molecule charge transfer studies.
Collapse
Affiliation(s)
- Stuart W Crane
- School of Chemistry, University of Bristol, Bristol, BS8 1TS, UK.
| | - Jason W L Lee
- Department of Chemistry, University of Oxford, Oxford, OX1 3TA, UK
| | | | - Daniel Rolles
- J.R. Macdonald Laboratory, Department of Physics, Kansas State University, Manhattan, KS 66506, USA
| |
Collapse
|
6
|
Goudreau ES, Boguslavskiy AE, Moffatt DJ, Makhija V, Hemsworth M, Lausten R, Marceau C, Wilkinson I, Stolow A. Time-stretched multi-hit 3D velocity map imaging of photoelectrons. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2023; 94:063002. [PMID: 37862509 DOI: 10.1063/5.0149897] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/09/2023] [Accepted: 05/30/2023] [Indexed: 10/22/2023]
Abstract
The 2D photoelectron velocity map imaging (VMI) technique is commonly employed in gas-phase molecular spectroscopy and dynamics investigations due to its ability to efficiently extract photoelectron spectra and angular distributions in a single experiment. However, the standard technique is limited to specific light-source polarization geometries. This has led to significant interest in the development of 3D VMI techniques, which are capable of measuring individual electron positions and arrival times, obtaining the full 3D distribution without the need for inversion, forward-convolution, or tomographic reconstruction approaches. Here, we present and demonstrate a novel time-stretched, 13-lens 3D VMI photoelectron spectrometer, which has sub-camera-pixel spatial resolution and 210 ps (σ) time-of-flight (TOF) resolution (currently limited by trigger jitter). We employ a kHz CMOS camera to image a standard 40 mm diameter microchannel plate (MCP)/phosphor anode detector (providing x and y positions), combined with a digitizer pick-off from the MCP anode to obtain the electron TOF. We present a detailed analysis of time-space correlation under data acquisition conditions which generate multiple electrons per laser shot, and demonstrate a major advantage of this time-stretched 3D VMI approach: that the greater spread in electron TOFs permits for an accurate time- and position-stamping of up to six electrons per laser shot at a 1 kHz repetition rate.
Collapse
Affiliation(s)
- E Scott Goudreau
- Department of Physics, University of Ottawa, Ottawa, Ontario K1N 6N5, Canada
- National Research Council Canada, Ottawa, Ontario K1A 0R6, Canada
| | - Andrey E Boguslavskiy
- Department of Physics, University of Ottawa, Ottawa, Ontario K1N 6N5, Canada
- National Research Council Canada, Ottawa, Ontario K1A 0R6, Canada
- Department of Chemistry, University of Ottawa, Ottawa, Ontario K1N 6N5, Canada
| | | | - Varun Makhija
- Department of Physics, University of Ottawa, Ottawa, Ontario K1N 6N5, Canada
- Department of Physics, University of Mary Washington, Fredericksburg, Virginia 22401, USA
| | - Michael Hemsworth
- Department of Physics, University of Ottawa, Ottawa, Ontario K1N 6N5, Canada
| | - Rune Lausten
- National Research Council Canada, Ottawa, Ontario K1A 0R6, Canada
| | - Claude Marceau
- National Research Council Canada, Ottawa, Ontario K1A 0R6, Canada
| | - Iain Wilkinson
- Institute for Electronic Structure Dynamics, Helmholtz-Zentrum Berlin für Materialien und Energie, Hahn-Meitner-Platz-1, D-14109 Berlin, Germany
| | - Albert Stolow
- Department of Physics, University of Ottawa, Ottawa, Ontario K1N 6N5, Canada
- National Research Council Canada, Ottawa, Ontario K1A 0R6, Canada
- Department of Chemistry, University of Ottawa, Ottawa, Ontario K1N 6N5, Canada
- NRC-uOttawa Joint Centre for Extreme Photonics, Ottawa, Ontario K1A 0R6, Canada
| |
Collapse
|
7
|
Margulis B, Horn KP, Reich DM, Upadhyay M, Kahn N, Christianen A, van der Avoird A, Groenenboom GC, Koch CP, Meuwly M, Narevicius E. Tomography of Feshbach resonance states. Science 2023; 380:77-81. [PMID: 37023184 DOI: 10.1126/science.adf9888] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/08/2023]
Abstract
Feshbach resonances are fundamental to interparticle interactions and become particularly important in cold collisions with atoms, ions, and molecules. In this work, we present the detection of Feshbach resonances in a benchmark system for strongly interacting and highly anisotropic collisions: molecular hydrogen ions colliding with noble gas atoms. The collisions are launched by cold Penning ionization, which exclusively populates Feshbach resonances that span both short- and long-range parts of the interaction potential. We resolved all final molecular channels in a tomographic manner using ion-electron coincidence detection. We demonstrate the nonstatistical nature of the final-state distribution. By performing quantum scattering calculations on ab initio potential energy surfaces, we show that the isolation of the Feshbach resonance pathways reveals their distinctive fingerprints in the collision outcome.
Collapse
Affiliation(s)
- Baruch Margulis
- Department of Chemical and Biological Physics, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Karl P Horn
- Dahlem Center for Complex Quantum Systems and Fachbereich Physik, Freie Universität Berlin, Arnimallee 14, 14195 Berlin, Germany
| | - Daniel M Reich
- Dahlem Center for Complex Quantum Systems and Fachbereich Physik, Freie Universität Berlin, Arnimallee 14, 14195 Berlin, Germany
| | - Meenu Upadhyay
- Department of Chemistry, University of Basel, Basel, Switzerland
| | | | - Arthur Christianen
- Max-Planck-Institut für Quantenoptik, Hans-Kopfermann-Strasse 1, D-85748 Garching, Germany
- Theoretical Chemistry, Institute for Molecules and Materials, Radboud University, Heyendaalseweg 135, 6525 AJ Nijmegen, Netherlands
| | - Ad van der Avoird
- Theoretical Chemistry, Institute for Molecules and Materials, Radboud University, Heyendaalseweg 135, 6525 AJ Nijmegen, Netherlands
| | - Gerrit C Groenenboom
- Theoretical Chemistry, Institute for Molecules and Materials, Radboud University, Heyendaalseweg 135, 6525 AJ Nijmegen, Netherlands
| | - Christiane P Koch
- Dahlem Center for Complex Quantum Systems and Fachbereich Physik, Freie Universität Berlin, Arnimallee 14, 14195 Berlin, Germany
| | - Markus Meuwly
- Department of Chemistry, University of Basel, Basel, Switzerland
| | - Edvardas Narevicius
- Department of Chemical and Biological Physics, Weizmann Institute of Science, Rehovot 7610001, Israel
- Department of Physics, Technische Universität, Dortmund, Germany
| |
Collapse
|
8
|
Colley J, Dynak NJ, Blais JRC, Duncan MA. Photodissociation Spectroscopy and Photofragment Imaging to Probe Fe +(Benzene) 1,2 Dissociation Energies. J Phys Chem A 2023; 127:2795-2804. [PMID: 36920853 PMCID: PMC10068738 DOI: 10.1021/acs.jpca.3c00735] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2023] [Revised: 03/03/2023] [Indexed: 03/16/2023]
Abstract
Tunable laser photodissociation spectroscopy measurements and photofragment imaging experiments are employed to investigate the dissociation energy of the Fe+(benzene) ion-molecule complex. Additional spectroscopy measurements determine the dissociation energy of Fe+(benzene)2. The dissociation energies for Fe+(benzene) determined from the threshold for the appearance of the Fe+ fragment (48.4 ± 0.2 kcal/mol) and photofragment imaging (≤49.3 ± 3.2 kcal/mol) agree nicely with each other and with the value determined previously by collision-induced dissociation (49.5 ± 2.9 kcal/mol), but they are lower than the values produced by computational chemistry at the density functional theory level using different functionals recommended for transition-metal chemistry. The threshold measurement for Fe+(benzene)2 (43.0 ± 0.2 kcal/mol) likewise agrees with the value (44.7 ± 3.8 kcal/mol) from previous collision-induced dissociation measurements.
Collapse
Affiliation(s)
- Jason
E. Colley
- Department of Chemistry, University
of Georgia, Athens, Georgia 30602, United States
| | - Nathan J. Dynak
- Department of Chemistry, University
of Georgia, Athens, Georgia 30602, United States
| | - John R. C. Blais
- Department of Chemistry, University
of Georgia, Athens, Georgia 30602, United States
| | - Michael A. Duncan
- Department of Chemistry, University
of Georgia, Athens, Georgia 30602, United States
| |
Collapse
|
9
|
Nesbitt DJ, Zolot AM, Roscioli JR, Ryazanov M. Nonequilibrium Scattering/Evaporation Dynamics at the Gas-Liquid Interface: Wetted Wheels, Self-Assembled Monolayers, and Liquid Microjets. Acc Chem Res 2023; 56:700-711. [PMID: 36848588 DOI: 10.1021/acs.accounts.2c00823] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/01/2023]
Abstract
ConspectusWe often teach or are taught in our freshman courses that there are three phases of matter─gas, liquid and solid─where the ordering reflects increasing complexity and strength of interaction between the molecular constituents. But arguably there is also a fascinating additional "phase" of matter associated with the microscopically thin interface (<10 molecules thick) between the gas and liquid, which is still poorly understood and yet plays a crucial role in fields ranging from chemistry of the marine boundary layer and atmospheric chemistry of aerosols to the passage of O2 and CO2 through alveolar sacs in our lungs. The work in this Account provides insights into three challenging new directions for the field, each embracing a rovibronically quantum-state-resolved perspective. Specifically, we exploit the powerful tools of chemical physics and laser spectroscopy to pose two fundamental questions. (i) At the microscopic level, do molecules in all internal quantum-states (e.g., vibrational, rotational, electronic) colliding with the interface "stick" with unit probability? (ii) Can reactive, scattering, and/or evaporating molecules at the gas-liquid interface avoid collisions with other species and thereby be observed in a truly "nascent" collision-free distribution of internal degrees of freedom? To help address these questions, we present studies in three different areas: (i) reactive scattering dynamics of F atoms with wetted-wheel gas-liquid interfaces, (ii) inelastic scattering of HCl from self-assembled monolayers (SAMs) via resonance-enhanced photoionization (REMPI)/velocity map imaging (VMI) methods, and (iii) quantum-state-resolved evaporation dynamics of NO at the gas-water interface. As a recurring theme, we find that molecular projectiles reactively, inelastically, or evaporatively scatter from the gas-liquid interface into internal quantum-state distributions substantially out of equilibrium with respect to the bulk liquid temperatures (TS). By detailed balance considerations, the data unambiguously indicate that even simple molecules exhibit rovibronic state dependences to how they "stick" to and eventually solvate into the gas-liquid interface. Such results serve to underscore the importance of quantum mechanics and nonequilibrium thermodynamics in energy transfer and chemical reactions at the gas-liquid interface. This nonequilibrium behavior may well make this rapidly emergent field of chemical dynamics at gas-liquid interfaces more complicated but even more interesting targets for further experimental/theoretical exploration.
Collapse
Affiliation(s)
- David J Nesbitt
- JILA, National Institute of Standards and Technology and University of Colorado, Boulder, Colorado 80309, United States
- Department of Physics, University of Colorado, Boulder, Colorado 80309, United States
- Department of Chemistry, University of Colorado, Boulder, Colorado 80309, United States
| | - Alex M Zolot
- Quantinuum, 303 S. Technology Ct., Broomfield, Colorado 80021, United States
| | - Joseph R Roscioli
- Aerodyne Research, Inc., 45 Manning Rd., Billerica, Massachusetts 01821, United States
| | - Mikhail Ryazanov
- JILA, National Institute of Standards and Technology and University of Colorado, Boulder, Colorado 80309, United States
| |
Collapse
|
10
|
Ito Y, Kominato M, Nakashima Y, Ohshimo K, Misaizu F. Fragment imaging in the infrared photodissociation of the Ar-tagged protonated water clusters H 3O +-Ar and H +(H 2O) 2-Ar. Phys Chem Chem Phys 2023; 25:9404-9412. [PMID: 36928842 DOI: 10.1039/d3cp00469d] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/08/2023]
Abstract
Infrared photodissociation of protonated water clusters with an Ar atom, namely H3O+-Ar and H+(H2O)2-Ar, was investigated by an imaging technique for mass-selected ions, to reveal the intra- and intermolecular vibrational dynamics. The presented system has the advantage of achieving fragment ion images with the cluster size- and mode-selective photoexcitation of each OH stretching vibration. Translational energy distributions of photofragments were obtained from the images upon the excitation of the bound (νb) and free (νf) OH stretching vibrations. The energy fractions in the translational motion were compared between νbI and νfI in H3O+-Ar or between νbII and νfII in H+(H2O)2-Ar, where the labels "I" and "II" represent H3O+-Ar and H+(H2O)2-Ar, respectively. In H3O+-Ar, the νfI excitation exhibited a smaller translational energy than νbI. This result can be explained by the higher vibrational energy of νfI, which enabled it to produce bending (ν4) excited H3O+ fragments that should be favored according to the energy-gap model. In contrast to H3O+-Ar, the νbII excitation of an Ar-tagged H2O subunit and the νfII excitation of an untagged H2O subunit resulted in very similar translational energy distributions in H+(H2O)2-Ar. The similar energy fractions independent of the excited H2O subunits suggested that the νbII and νfII excited states relaxed into a common intermediate state, in which the vibrational energy was delocalized within the H2O-H+-H2O moiety. However, the translational energy distributions for H+(H2O)2-Ar did not agree with a statistical dissociation model, which implied another aspect of the process, that is, Ar dissociation via incomplete energy randomization in the whole H+(H2O)2-Ar cluster.
Collapse
Affiliation(s)
- Yuri Ito
- Department of Chemistry, Graduate School of Science, Tohoku University, 6-3 Aoba, Aramaki, Aoba-ku, Sendai 980-8578, Japan.
| | - Mizuhiro Kominato
- Department of Chemistry, Graduate School of Science, Tohoku University, 6-3 Aoba, Aramaki, Aoba-ku, Sendai 980-8578, Japan.
| | - Yuji Nakashima
- Department of Chemistry, Graduate School of Science, Tohoku University, 6-3 Aoba, Aramaki, Aoba-ku, Sendai 980-8578, Japan.
| | - Keijiro Ohshimo
- Department of Chemistry, Graduate School of Science, Tohoku University, 6-3 Aoba, Aramaki, Aoba-ku, Sendai 980-8578, Japan.
| | - Fuminori Misaizu
- Department of Chemistry, Graduate School of Science, Tohoku University, 6-3 Aoba, Aramaki, Aoba-ku, Sendai 980-8578, Japan.
| |
Collapse
|
11
|
Colley JE, Dynak NJ, Blais JRC, Duncan MA. Photodissociation Spectroscopy and Photofragment Imaging of the Fe +(Acetylene) Complex. J Phys Chem A 2023; 127:1244-1251. [PMID: 36701377 DOI: 10.1021/acs.jpca.2c08456] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Tunable laser photodissociation spectroscopy in the 700-400 nm region and photofragment imaging experiments are employed to investigate the Fe+(acetylene) ion-molecule complex. At energies above a threshold at 679 nm, continuous dissociation is detected throughout the visible wavelength region, with regions of broad structure. Comparison to the spectrum predicted by time-dependent density functional theory (TD-DFT) indicates that the complex has a quartet ground state. The dissociation threshold for Fe+(acetylene) at 679 nm provides the dissociation energy on the quartet potential energy surface. Correction for the atomic quartet-sextet spin state energy difference provides an adiabatic dissociation energy of 36.8 ± 0.2 kcal/mol. Photofragment imaging of the Fe+ photoproduct produced at 603.5 nm produces significant kinetic energy release (KER). The photon energy and the maximum value of the KER provide an upper limit on the dissociation energy of D0 ≤ 34.6 ± 3.2 kcal/mol. The dissociation energies determined from the spectroscopy and photofragment imaging experiments agree nicely with the value determined previously by collision-induced dissociation (38.0 ± 2.6 kcal/mol). However, both values are significantly lower than those produced by computational chemistry at the DFT level using different functionals recommended for transition-metal chemistry.
Collapse
Affiliation(s)
- Jason E Colley
- Department of Chemistry, University of Georgia, Athens, Georgia 30602, United States
| | - Nathan J Dynak
- Department of Chemistry, University of Georgia, Athens, Georgia 30602, United States
| | - John R C Blais
- Department of Chemistry, University of Georgia, Athens, Georgia 30602, United States
| | - Michael A Duncan
- Department of Chemistry, University of Georgia, Athens, Georgia 30602, United States
| |
Collapse
|
12
|
Lockwood SP, Metz RB. Photofragment imaging differentiates between one- and two-photon dissociation pathways in MgI . J Chem Phys 2023; 158:054303. [PMID: 36754811 DOI: 10.1063/5.0134668] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
The bond strength and photodissociation dynamics of MgI+ are determined by a combination of theory, photodissociation spectroscopy, and photofragment velocity map imaging. From 17 000 to 21 500 cm-1, the photodissociation spectrum of MgI+ is broad and unstructured; photofragment images in this region show perpendicular anisotropy, which is consistent with absorption to the repulsive wall of the (1) Ω = 1 or (2) Ω = 1 states followed by direct dissociation to ground state products Mg+ (2S) + I (2P3/2). Analysis of photofragment images taken at photon energies near the threshold gives a bond dissociation energy D0(Mg+-I) = 203.0 ± 1.8 kJ/mol (2.10 ± 0.02 eV; 17 000 ± 150 cm-1). At photon energies of 33 000-41 000 cm-1, exclusively I+ fragments are formed. Over most of this region, the formation of I+ is not energetically allowed via one-photon absorption from the ground state of MgI+. Images show the observed product is due to resonance enhanced two-photon dissociation. The photodissociation spectrum from 33 000 to 38 500 cm-1 shows vibrational structure, giving an average excited state vibrational spacing of 227 cm-1. This is consistent with absorption to the (3) Ω = 0+ state from ν = 0, 1 of the (1) Ω = 0+ ground state; from the (3) Ω = 0+ state, absorption of a second photon results in dissociation to Mg* (3P° J) + I+ (3PJ). From 38 500 to 41 000 cm-1, the spectrum is broad and unstructured. We attribute this region of the spectrum to one-photon dissociation of vibrationally hot MgI+ at low energy and ground state MgI+ at higher energy to form Mg (1S) + I+ (3PJ) products.
Collapse
Affiliation(s)
- Schuyler P Lockwood
- Department of Chemistry, University of Massachusetts Amherst, Amherst, Massachusetts 01002, USA
| | - Ricardo B Metz
- Department of Chemistry, University of Massachusetts Amherst, Amherst, Massachusetts 01002, USA
| |
Collapse
|
13
|
Karsili TNV, Marchetti B, Lester MI, Ashfold MNR. Electronic Absorption Spectroscopy and Photochemistry of Criegee Intermediates. Photochem Photobiol 2023; 99:4-18. [PMID: 35713380 DOI: 10.1111/php.13665] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2022] [Accepted: 06/14/2022] [Indexed: 01/26/2023]
Abstract
Interest in Criegee intermediates (CIs), often termed carbonyl oxides, and their role in tropospheric chemistry has grown massively since the demonstration of laboratory-based routes to their formation and characterization in the gas phase. This article reviews current knowledge regarding the electronic spectroscopy of atmospherically relevant CIs like CH2 OO, CH3 CHOO, (CH3 )2 COO and larger CIs like methyl vinyl ketone oxide and methacrolein oxide that are formed in the ozonolysis of isoprene, and of selected conjugated carbene-derived CIs of interest in the synthetic chemistry community. Of the aforementioned atmospherically relevant CIs, all except CH2 OO and (CH3 )2 COO exist in different conformers which, under tropospheric conditions, can display strikingly different thermal loss rates via unimolecular and bimolecular processes. Calculated photolysis rates based on their absorption properties suggest that solar photolysis will rarely be a significant contributor to the total loss rate for any CI under tropospheric conditions. Nonetheless, there is ever-growing interest in the absorption cross sections and primary photochemistry of CIs following excitation to the strongly absorbing 1 ππ* state, and how this varies with CI, with conformer and with excitation wavelength. The later part of this review surveys the photochemical data reported to date, including a range of studies that demonstrate prompt photo-induced fission of the terminal O-O bond, and speculates about possible alternate decay processes that could occur following non-adiabatic coupling to, and dissociation from, highly internally excited levels of the electronic ground state of a CI.
Collapse
Affiliation(s)
| | | | - Marsha I Lester
- Department of Chemistry, University of Pennsylvania, Philadelphia, PA
| | | |
Collapse
|
14
|
Oelmann JH, Heldt T, Guth L, Nauta J, Lackmann N, Wössner V, Kokh S, Pfeifer T, López-Urrutia JRC. Photoelectron tomography with an intra-cavity velocity-map imaging spectrometer at 100 MHz repetition rate. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2022; 93:123303. [PMID: 36586896 DOI: 10.1063/5.0104679] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/20/2022] [Accepted: 11/16/2022] [Indexed: 06/17/2023]
Abstract
We present a compact velocity-map imaging (VMI) spectrometer for photoelectron imaging at 100 MHz repetition rate. Ultrashort pulses from a near-infrared frequency comb laser are amplified in a polarization-insensitive passive femtosecond enhancement cavity. In the focus, multi-photon ionization (MPI) of gas-phase atoms is studied tomographically by rotating the laser polarization. We demonstrate the functioning of the VMI spectrometer by reconstructing photoelectron angular momentum distributions from xenon MPI. Our intra-cavity VMI setup collects electron energy spectra at high rates, with the advantage of transferring the coherence of the cavity-stabilized femtosecond pulses to the electrons. In addition, the setup will allow studies of strong-field effects in nanometric tips.
Collapse
Affiliation(s)
- J-H Oelmann
- Max-Planck-Institut für Kernphysik, Saupfercheckweg 1, 69117 Heidelberg, Germany
| | - T Heldt
- Max-Planck-Institut für Kernphysik, Saupfercheckweg 1, 69117 Heidelberg, Germany
| | - L Guth
- Max-Planck-Institut für Kernphysik, Saupfercheckweg 1, 69117 Heidelberg, Germany
| | - J Nauta
- Max-Planck-Institut für Kernphysik, Saupfercheckweg 1, 69117 Heidelberg, Germany
| | - N Lackmann
- Max-Planck-Institut für Kernphysik, Saupfercheckweg 1, 69117 Heidelberg, Germany
| | - V Wössner
- Max-Planck-Institut für Kernphysik, Saupfercheckweg 1, 69117 Heidelberg, Germany
| | - S Kokh
- Max-Planck-Institut für Kernphysik, Saupfercheckweg 1, 69117 Heidelberg, Germany
| | - T Pfeifer
- Max-Planck-Institut für Kernphysik, Saupfercheckweg 1, 69117 Heidelberg, Germany
| | | |
Collapse
|
15
|
Yifrach Y, Baraban JH, Bar I. Kinetic Energy-Broadened Spatial Map Imaging for Recovering Dynamical Information. J Phys Chem A 2022; 126:6767-6779. [DOI: 10.1021/acs.jpca.2c04444] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
|
16
|
Accurate measurements of the bond dissociation energies of 14N2, 14N15N and 15N2. FUNDAMENTAL RESEARCH 2022. [DOI: 10.1016/j.fmre.2022.08.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
|
17
|
Golibrzuch K, Schwabe S, Zhong T, Papendorf K, Wodtke AM. Application of an Event-Based Camera for Real-Time Velocity Resolved Kinetics. J Phys Chem A 2022; 126:2142-2148. [PMID: 35319892 PMCID: PMC8996233 DOI: 10.1021/acs.jpca.2c00806] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
![]()
We describe here
the application of an inexpensive event-based/neuromorphic
camera in an ion imaging experiment operated at 1 kHz detection rate
to study real-time velocity-resolved kinetics of thermal desorption.
Such measurements involve a single gas pulse to initiate a time-dependent
desorption process and a high repetition rate laser, where each pulse
of the laser is used to produce an ion image. The sequence of ion
images allows the time dependence of the desorption flux to be followed
in real time. In previous work where a conventional framing camera
was used, the large number of megapixel-sized images required data
transfer and storage rates of up to 16 GB/s. This necessitated a large
onboard memory that was quickly filled and limited continuous measurement
to only a few seconds. Read-out of the memory became the bottleneck
to the rate of data acquisition. We show here that since most pixels
in each ion image contain no data, the data rate can be dramatically
reduced by using an event-based/neuromorphic camera. The data stream
is thus reduced to the intensity and location information on the pixels
that are lit up by each ion event together with a time-stamp indicating
the arrival time of an ion at the detector. This dramatically increases
the duty cycle of the method and provides insights for the execution
of other high rep-rate ion imaging experiments.
Collapse
Affiliation(s)
- Kai Golibrzuch
- Max-Planck-Institute for Multidisciplinary Sciences, Am Fassberg 11, D-37077 Goettingen, Germany.,Institute for Physical Chemistry, Georg-August-University Goettingen, Tammannstrasse 6, D- 37077 Goettingen, Germany
| | - Sven Schwabe
- Max-Planck-Institute for Multidisciplinary Sciences, Am Fassberg 11, D-37077 Goettingen, Germany.,Institute for Physical Chemistry, Georg-August-University Goettingen, Tammannstrasse 6, D- 37077 Goettingen, Germany.,Institute for Nanophotonics, Hans-Adolf-Krebs-Weg 1, D-37077 Goettingen, Germany
| | - Tianli Zhong
- Max-Planck-Institute for Multidisciplinary Sciences, Am Fassberg 11, D-37077 Goettingen, Germany.,Institute for Physical Chemistry, Georg-August-University Goettingen, Tammannstrasse 6, D- 37077 Goettingen, Germany
| | - Kim Papendorf
- Max-Planck-Institute for Multidisciplinary Sciences, Am Fassberg 11, D-37077 Goettingen, Germany.,Institute for Physical Chemistry, Georg-August-University Goettingen, Tammannstrasse 6, D- 37077 Goettingen, Germany
| | - Alec M Wodtke
- Max-Planck-Institute for Multidisciplinary Sciences, Am Fassberg 11, D-37077 Goettingen, Germany.,Institute for Physical Chemistry, Georg-August-University Goettingen, Tammannstrasse 6, D- 37077 Goettingen, Germany
| |
Collapse
|
18
|
Abstract
Advances in atomic, molecular, and optical physics techniques allowed the cooling of simple molecules down to the ultracold regime ([Formula: see text]1 mK) and opened opportunities to study chemical reactions with unprecedented levels of control. This review covers recent developments in studying bimolecular chemistry at ultralow temperatures. We begin with a brief overview of methods for producing, manipulating, and detecting ultracold molecules. We then survey experimental works that exploit the controllability of ultracold molecules to probe and modify their long-range interactions. Further combining the use of physical chemistry techniques such as mass spectrometry and ion imaging significantly improved the detection of ultracold reactions and enabled explorations of their dynamics in the short range. We discuss a series of studies on the reaction KRb + KRb → K2 + Rb2 initiated below 1 [Formula: see text]K, including the direct observation of a long-lived complex, the demonstration of product rotational state control via conserved nuclear spins, and a test of the statistical model using the complete quantum state distribution of the products. Expected final online publication date for the Annual Review of Physical Chemistry, Volume 73 is April 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.
Collapse
Affiliation(s)
- Yu Liu
- Time and Frequency Division, National Institute of Standards and Technology, Boulder, Colorado 80305, USA; .,Department of Physics, University of Colorado, Boulder, Colorado 80309, USA
| | - Kang-Kuen Ni
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts 02138, USA; .,Harvard-Massachusetts Institute of Technology Center for Ultracold Atoms, Cambridge, Massachusetts 02138, USA
| |
Collapse
|
19
|
Ploenes L, Straňák P, Gao H, Küpper J, Willitsch S. A novel crossed-molecular-beam experiment for investigating reactions of state- and conformationally selected strong-field-seeking molecules. Mol Phys 2021. [DOI: 10.1080/00268976.2021.1965234] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Affiliation(s)
- L. Ploenes
- Department of Chemistry, University of Basel, Basel, Switzerland
| | - P. Straňák
- Department of Chemistry, University of Basel, Basel, Switzerland
| | - H. Gao
- Department of Chemistry, University of Basel, Basel, Switzerland
| | - J. Küpper
- Center for Free-Electron Laser Science, Deutsches Elektronen-Synchrotron DESY, Hamburg, Germany
- Center for Ultrafast Imaging, Universität Hamburg, Hamburg, Germany
- Department of Physics, Universität Hamburg, Hamburg, Germany
- Department of Chemistry, Universität Hamburg, Hamburg, Germany
| | - S. Willitsch
- Department of Chemistry, University of Basel, Basel, Switzerland
| |
Collapse
|
20
|
Lockwood SP, Chunga T, Metz RB. Bonding, Thermodynamics, and Dissociation Dynamics of NiO + and NiS + Determined by Photofragment Imaging and Theory. J Phys Chem A 2021; 125:7425-7436. [PMID: 34427080 DOI: 10.1021/acs.jpca.1c05405] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We use photofragment ion imaging and ab initio calculations to determine the bond strength and photodissociation dynamics of the nickel oxide (NiO+) and nickel sulfide (NiS+) cations. NiO+ photodissociates broadly from 20350 to 32000 cm-1, forming ground state products Ni+(2D) + O(3P) below ∼29000 cm-1. Above this energy, Ni+(4F) + O(3P) products become accessible and dominate over the ground state channel. In certain images, product spin-orbit levels are resolved, and spin-orbit propensities are determined. Image anisotropy and the results of MRCI calculations suggest NiO+ photodissociates via a 3 4Σ- ← X 4Σ- transition above the Ni+(4F) threshold and via 3 4Σ-, 2 4Σ-, and/or 2 4Π and 3 4Π excited states below the 4F threshold. The photodissociation spectrum of NiS+ from 19900 to 23200 cm-1 is highly structured, with ∼12 distinct vibronic peaks, each containing underlying substructure. Above 21600 cm-1, the Ni+(2D5/2) + S(3P) and Ni+(2D3/2) + S(3P) product spin-orbit channels compete, with a branching ratio of ∼2:1. At lower energy, Ni+(2D5/2) is formed exclusively, and S(3P2) and S(3P1) spin-orbit channels are resolved. MRCI calculations predict the ground state of NiS+ to be one of two nearly degenerate states, the 1 4Σ- and 1 4Δ. Based on images and spectra, the ground state of NiS+ is assigned as 4Δ7/2, with the 1 4Σ3/2- and 1 4Σ1/2- states 81 ± 30 and 166 ± 50 cm-1 higher in energy, respectively. The majority of the photodissociation spectrum is assigned to transitions from the 1 4Δ state to two overlapping, predissociative excited 4Δ states. Our D0 measurements for NiO+ (D0 = 244.6 ± 2.4 kJ/mol) and NiS+ (D0 = 240.3 ± 1.4 kJ/mol) are more precise and closer to each other than previously reported values. Finally, using a recent measurement of D0(NiS), we derive a more precise value for IE (NiS): 8.80 ± 0.02 eV (849 ± 1.7 kJ/mol).
Collapse
Affiliation(s)
- Schuyler P Lockwood
- Department of Chemistry, University of Massachusetts Amherst, Amherst, Massachusetts 01003, United States
| | - Tala Chunga
- Department of Chemistry, University of Massachusetts Amherst, Amherst, Massachusetts 01003, United States
| | - Ricardo B Metz
- Department of Chemistry, University of Massachusetts Amherst, Amherst, Massachusetts 01003, United States
| |
Collapse
|
21
|
Abstract
We present a novel binding mechanism where a neutral Rydberg atom and an atomic ion form a molecular bound state at a large internuclear distance. The binding mechanism is based on Stark shifts and level crossings that are induced in the Rydberg atom due to the electric field of the ion. At particular internuclear distances between the Rydberg atom and the ion, potential wells occur that can hold atom–ion molecular bound states. Apart from the binding mechanism, we describe important properties of the long-range atom–ion Rydberg molecule, such as its lifetime and decay paths, its vibrational and rotational structure, and its large dipole moment. Furthermore, we discuss methods of how to produce and detect it. The unusual properties of the long-range atom–ion Rydberg molecule give rise to interesting prospects for studies of wave packet dynamics in engineered potential energy landscapes.
Collapse
|
22
|
Auerbach DJ, Tully JC, Wodtke AM. Chemical dynamics from the gas‐phase to surfaces. ACTA ACUST UNITED AC 2021. [DOI: 10.1002/ntls.10005] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Affiliation(s)
- Daniel J. Auerbach
- Institut für physikalische Chemie Georg‐August Universität Göttingen Göttingen Germany
- Abteilung für Dynamik an Oberflächen Max‐Planck‐Institut für biophysikalische Chemie Göttingen Germany
| | - John C. Tully
- Department of Chemistry Yale University New Haven Connecticut USA
| | - Alec M. Wodtke
- Institut für physikalische Chemie Georg‐August Universität Göttingen Göttingen Germany
- Abteilung für Dynamik an Oberflächen Max‐Planck‐Institut für biophysikalische Chemie Göttingen Germany
| |
Collapse
|
23
|
Yifrach Y, Rahimi R, Portnov A, Baraban JH, Bar I. Maximal kinetic energy and angular distribution analysis of spatial map imaging: Application to photoelectrons from a single quantum state of H 2O. J Chem Phys 2021; 154:134201. [PMID: 33832240 DOI: 10.1063/5.0046015] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Dynamical or spatial properties of charged species can be obtained using electrostatic lenses by velocity map imaging (VMI) or spatial map imaging (SMI), respectively. Here, we report an approach for extracting dynamical and spatial information from patterns in SMI images that map the initial coordinates, velocity vectors, and angular distributions of charged particles onto the detector, using the same apparatus as in VMI. Deciphering these patterns required analysis and modeling, involving both their predictions from convolved spatial and velocity distributions and fitting observed images to kinetic energies (KEs) and anisotropy parameters (βs). As the first demonstration of this capability of SMI, the ensuing photoelectrons resulting from (2 + 1) resonant ionization of water in a selected rotational state were chosen to provide a rigorous basis for comparison to VMI. Operation with low acceleration voltages led to a measured SMI pattern with a unique vertical intensity profile that could be least-squares fitted to yield KE and β, in good agreement with VMI measurement. Due to the potential for improved resolution and the extended KE range achievable by this new technique, we expect that it might augment VMI in applications that require the analysis of charged particles and particularly in processes with high KE release.
Collapse
Affiliation(s)
- Yair Yifrach
- Department of Physics, Ben-Gurion University of the Negev, Beer-Sheva 8410501, Israel
| | - Rami Rahimi
- Department of Physics, Ben-Gurion University of the Negev, Beer-Sheva 8410501, Israel
| | - Alexander Portnov
- Department of Physics, Ben-Gurion University of the Negev, Beer-Sheva 8410501, Israel
| | - Joshua H Baraban
- Department of Chemistry, Ben-Gurion University of the Negev, Beer-Sheva 8410501, Israel
| | - Ilana Bar
- Department of Physics, Ben-Gurion University of the Negev, Beer-Sheva 8410501, Israel
| |
Collapse
|
24
|
Matthaei CT, Mukhopadhyay DP, Fischer I. Photodissociation of Benzoyl Chloride: A Velocity Map Imaging Study Using VUV Detection of Chlorine Atoms. J Phys Chem A 2021; 125:2816-2825. [PMID: 33819043 DOI: 10.1021/acs.jpca.0c11236] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
UV photodissociation of benzoyl chloride, Ph-CO-Cl, is associated with the loss of a chlorine atom. Here we excite benzoyl chloride to the S1, S2, and S3 excited states at 237, 253, 265, and 279.6 nm and detect the Cl photofragment by [1 + 1'] photoionization using 118.9 nm VUV radiation. The translational energy distribution of the Cl atom is measured by velocity map ion imaging. An isotropic image and a unimodal translational energy distribution are observed at all dissociation wavelengths, and a fraction of 18-20% of the excess energy is released into translation. The results indicate a dissociation that predominately proceeds from the vibrationally hot S0 ground state, although the observed translational energy release deviates significantly from a prior distribution. However, the impulsive model does also not represent the translational energy release. As a Cl/Cl* branching ratio of 9:1 or more is observed in one-color experiments at 235 nm, we conclude that direct dissociation from excited electronic states contributes only to a minor extent.
Collapse
Affiliation(s)
- Christian T Matthaei
- Institute of Physical and Theoretical Chemistry, University of Würzburg, Am Hubland, D-97074 Würzburg, Germany
| | - Deb Pratim Mukhopadhyay
- Institute of Physical and Theoretical Chemistry, University of Würzburg, Am Hubland, D-97074 Würzburg, Germany
| | - Ingo Fischer
- Institute of Physical and Theoretical Chemistry, University of Würzburg, Am Hubland, D-97074 Würzburg, Germany
| |
Collapse
|
25
|
Xu A, Ma YJ, Yan D, Li FF, Liu JX, Wang FY. Advanced techniques for quantum-state specific reaction dynamics of gas phase metal atoms. CHINESE J CHEM PHYS 2021. [DOI: 10.1063/1674-0068/cjcp2102026] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Affiliation(s)
- Ang Xu
- Department of Chemistry and Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials, Collaborative Innovation Center of Chemistry for Energy Materials (iChEM), Fudan University, Shanghai 200433, China
| | - Yu-jie Ma
- Department of Chemistry and Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials, Collaborative Innovation Center of Chemistry for Energy Materials (iChEM), Fudan University, Shanghai 200433, China
| | - Dong Yan
- Department of Chemistry and Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials, Collaborative Innovation Center of Chemistry for Energy Materials (iChEM), Fudan University, Shanghai 200433, China
| | - Fang-fang Li
- Department of Chemistry and Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials, Collaborative Innovation Center of Chemistry for Energy Materials (iChEM), Fudan University, Shanghai 200433, China
| | - Jia-xing Liu
- Department of Chemistry and Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials, Collaborative Innovation Center of Chemistry for Energy Materials (iChEM), Fudan University, Shanghai 200433, China
| | - Feng-yan Wang
- Department of Chemistry and Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials, Collaborative Innovation Center of Chemistry for Energy Materials (iChEM), Fudan University, Shanghai 200433, China
| |
Collapse
|
26
|
Hua ZF, Zhao YX, Li YQ, Hu GM, Chen Y, Zhao DF. Ion-neutral photofragment coincidence imaging of photodissociation dynamics of ionic species. CHINESE J CHEM PHYS 2021. [DOI: 10.1063/1674-0068/cjcp2007119] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Affiliation(s)
- Ze-feng Hua
- CAS Center for Excellence in Quantum Information and Quantum Physics, Hefei National Laboratory for Physical Sciences at the Microscale, and Department of Chemical Physics, University of Science and Technology of China, Hefei 230026, China
| | - Yun-xiao Zhao
- CAS Center for Excellence in Quantum Information and Quantum Physics, Hefei National Laboratory for Physical Sciences at the Microscale, and Department of Chemical Physics, University of Science and Technology of China, Hefei 230026, China
| | - You-qing Li
- CAS Center for Excellence in Quantum Information and Quantum Physics, Hefei National Laboratory for Physical Sciences at the Microscale, and Department of Chemical Physics, University of Science and Technology of China, Hefei 230026, China
| | - Gao-ming Hu
- CAS Center for Excellence in Quantum Information and Quantum Physics, Hefei National Laboratory for Physical Sciences at the Microscale, and Department of Chemical Physics, University of Science and Technology of China, Hefei 230026, China
| | - Yang Chen
- CAS Center for Excellence in Quantum Information and Quantum Physics, Hefei National Laboratory for Physical Sciences at the Microscale, and Department of Chemical Physics, University of Science and Technology of China, Hefei 230026, China
| | - Dong-feng Zhao
- CAS Center for Excellence in Quantum Information and Quantum Physics, Hefei National Laboratory for Physical Sciences at the Microscale, and Department of Chemical Physics, University of Science and Technology of China, Hefei 230026, China
| |
Collapse
|
27
|
Hu MG, Liu Y, Nichols MA, Zhu L, Quéméner G, Dulieu O, Ni KK. Nuclear spin conservation enables state-to-state control of ultracold molecular reactions. Nat Chem 2021; 13:435-440. [PMID: 33380743 DOI: 10.1038/s41557-020-00610-0] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2020] [Accepted: 11/18/2020] [Indexed: 12/13/2022]
Abstract
Quantum-state control of reactive systems has enabled microscopic probes of underlying interaction potentials and the alteration of reaction rates using quantum statistics. However, extending such control to the quantum states of reaction outcomes remains challenging. Here, we realize this goal by utilizing the conservation of nuclear spins throughout the reaction. Using resonance-enhanced multiphoton ionization spectroscopy to investigate the products formed in bimolecular reactions between ultracold KRb molecules we find that the system retains a near-perfect memory of the reactants' nuclear spins, manifested as a strong parity preference for the rotational states of the products. We leverage this effect to alter the occupation of these product states by changing the coherent superposition of initial nuclear spin states with an external magnetic field. In this way, we are able to control both the inputs and outputs of a reaction with quantum-state resolution. The techniques demonstrated here open up the possibilities to study quantum entanglement between reaction products and ultracold reaction dynamics at the state-to-state level.
Collapse
Affiliation(s)
- Ming-Guang Hu
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA, USA. .,Department of Physics, Harvard University, Cambridge, MA, USA. .,Harvard-MIT Center for Ultracold Atoms, Cambridge, MA, USA.
| | - Yu Liu
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA, USA.,Department of Physics, Harvard University, Cambridge, MA, USA.,Harvard-MIT Center for Ultracold Atoms, Cambridge, MA, USA
| | - Matthew A Nichols
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA, USA.,Department of Physics, Harvard University, Cambridge, MA, USA.,Harvard-MIT Center for Ultracold Atoms, Cambridge, MA, USA
| | - Lingbang Zhu
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA, USA.,Department of Physics, Harvard University, Cambridge, MA, USA.,Harvard-MIT Center for Ultracold Atoms, Cambridge, MA, USA
| | - Goulven Quéméner
- Université Paris-Saclay, CNRS, Laboratoire Aimé Cotton, Orsay, France
| | - Olivier Dulieu
- Université Paris-Saclay, CNRS, Laboratoire Aimé Cotton, Orsay, France
| | - Kang-Kuen Ni
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA, USA. .,Department of Physics, Harvard University, Cambridge, MA, USA. .,Harvard-MIT Center for Ultracold Atoms, Cambridge, MA, USA.
| |
Collapse
|
28
|
Paliwal P, Deb N, Reich DM, Avoird AVD, Koch CP, Narevicius E. Determining the nature of quantum resonances by probing elastic and reactive scattering in cold collisions. Nat Chem 2020; 13:94-98. [PMID: 33257885 DOI: 10.1038/s41557-020-00578-x] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2020] [Accepted: 10/14/2020] [Indexed: 11/09/2022]
Abstract
Scattering resonances play a central role in collision processes in physics and chemistry. They help build an intuitive understanding of the collision dynamics due to the spatial localization of the scattering wavefunctions. For resonances that are localized in the reaction region, located at short separation behind the centrifugal barrier, sharp peaks in the reaction rates are the characteristic signature, observed recently with state-of-the-art experiments in low-energy collisions. If, however, the localization occurs outside of the reaction region, mostly the elastic scattering is modified. This may occur due to above-barrier resonances, the quantum analogue of classical orbiting. By probing both elastic and inelastic scattering of metastable helium with deuterium molecules in merged-beam experiments, we differentiate between the nature of quantum resonances-tunnelling resonances versus above-barrier resonances-and corroborate our findings by calculating the corresponding scattering wavefunctions.
Collapse
Affiliation(s)
- Prerna Paliwal
- Department of Chemical and Biological Physics, Weizmann Institute of Science, Rehovot, Israel
| | - Nabanita Deb
- Department of Chemical and Biological Physics, Weizmann Institute of Science, Rehovot, Israel
| | - Daniel M Reich
- Dahlem Center for Complex Quantum Systems and Fachbereich Physik, Freie Universität Berlin, Berlin, Germany
| | - Ad van der Avoird
- Institute of Theoretical Chemistry, Institute for Molecules and Materials, Radboud University, Nijmegen, Netherlands
| | - Christiane P Koch
- Dahlem Center for Complex Quantum Systems and Fachbereich Physik, Freie Universität Berlin, Berlin, Germany.
| | - Edvardas Narevicius
- Department of Chemical and Biological Physics, Weizmann Institute of Science, Rehovot, Israel.
| |
Collapse
|
29
|
Rittgers BM, Leicht D, Duncan MA. Cation-π Complexes of Silver Studied with Photodissociation and Velocity-Map Imaging. J Phys Chem A 2020; 124:9166-9176. [PMID: 33103909 DOI: 10.1021/acs.jpca.0c08498] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Ag+(aromatic) ion-molecule complexes of benzene, toluene, or furan are generated in the gas phase by laser vaporization in a supersonic expansion. These ions are mass selected in a time-of-flight spectrometer and studied with ultraviolet laser photodissociation and photofragment imaging. UV laser excitation results in dissociative charge transfer (DCT) for these ions, producing neutral silver atom and the respective aromatic cation as the photofragments. Velocity-map imaging and slice imaging techniques are employed to investigate the kinetic energy release in these photodissociation processes. In each case, DCT produces significant kinetic energy, and evidence is also found for excitation of the internal rovibrational degrees of freedom for the molecular cations. Analysis of the kinetic energy release together with the known ionization energies of silver and the molecular ligands provides new information on the cation-π bond energies.
Collapse
Affiliation(s)
- Brandon M Rittgers
- Department of Chemistry, University of Georgia, Athens, Georgia 30602, United States
| | - Daniel Leicht
- Department of Chemistry, University of Georgia, Athens, Georgia 30602, United States
| | - Michael A Duncan
- Department of Chemistry, University of Georgia, Athens, Georgia 30602, United States
| |
Collapse
|
30
|
Allum F, Mason R, Burt M, Slater CS, Squires E, Winter B, Brouard M. Post extraction inversion slice imaging for 3D velocity map imaging experiments. Mol Phys 2020. [DOI: 10.1080/00268976.2020.1842531] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Affiliation(s)
- Felix Allum
- The Chemistry Research Laboratory, Department of Chemistry, University of Oxford, Oxford, UK
| | - Robert Mason
- The Chemistry Research Laboratory, Department of Chemistry, University of Oxford, Oxford, UK
| | - Michael Burt
- The Chemistry Research Laboratory, Department of Chemistry, University of Oxford, Oxford, UK
| | - Craig S. Slater
- The Chemistry Research Laboratory, Department of Chemistry, University of Oxford, Oxford, UK
| | - Eleanor Squires
- The Chemistry Research Laboratory, Department of Chemistry, University of Oxford, Oxford, UK
| | - Benjamin Winter
- The Chemistry Research Laboratory, Department of Chemistry, University of Oxford, Oxford, UK
| | - Mark Brouard
- The Chemistry Research Laboratory, Department of Chemistry, University of Oxford, Oxford, UK
| |
Collapse
|
31
|
Vinklárek IS, Rakovský J, Poterya V, Fárník M. Clustering and multiphoton effects in velocity map imaging of methyl chloride. Mol Phys 2020. [DOI: 10.1080/00268976.2020.1823507] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Affiliation(s)
- I. S. Vinklárek
- J. Heyrovský Institute of Physical Chemistry, Czech Academy of Sciences, Prague, Czech Republic
- Faculty of Mathematics and Physics, Charles University, Prague, Czech Republic
| | - J. Rakovský
- J. Heyrovský Institute of Physical Chemistry, Czech Academy of Sciences, Prague, Czech Republic
| | - V. Poterya
- J. Heyrovský Institute of Physical Chemistry, Czech Academy of Sciences, Prague, Czech Republic
| | - M. Fárník
- J. Heyrovský Institute of Physical Chemistry, Czech Academy of Sciences, Prague, Czech Republic
| |
Collapse
|
32
|
Plomp V, Gao Z, van de Meerakker SYT. A velocity map imaging apparatus optimised for high-resolution crossed molecular beam experiments. Mol Phys 2020. [DOI: 10.1080/00268976.2020.1814437] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Affiliation(s)
- Vikram Plomp
- Institute for Molecules and Materials, Radboud University, Nijmegen, The Netherlands
| | - Zhi Gao
- Institute for Molecules and Materials, Radboud University, Nijmegen, The Netherlands
| | | |
Collapse
|
33
|
Yifrach Y, Rahimi R, Portnov A, Bar I. A new imaging-based method for alignment of multiple laser beams. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2020; 237:118404. [PMID: 32361520 DOI: 10.1016/j.saa.2020.118404] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/30/2019] [Revised: 04/20/2020] [Accepted: 04/20/2020] [Indexed: 06/11/2023]
Abstract
A new method for multiple laser beams alignment, useful in a wide range of spectroscopies, is proposed and demonstrated. The method, based on the coupling of spatial map imaging (SMI) with velocity map imaging (VMI), aided beams visualization, through interrogation of the ionization signal of different species in a time-of-flight mass spectrometer. This approach is very effective for alignment and for evaluating the spatial overlap of laser beams with a molecular beam. This was demonstrated by monitoring the resonant two-photon ionization spectrum of 2-phenylethylamine (PEA) monomer and its hydrated (PEA-H2O) cluster and the ionization-loss stimulated Raman spectrum of the cluster, via VMIs accumulation, as a function of the exciting laser wavelength. The former permitted immediate classification of the features in the spectrum, corresponding to the molecular ion or the cluster. The proposed methodology will be useful in other challenging multiple laser beam experiments for spectroscopic studies and is expected to improve extensively their outcome.
Collapse
Affiliation(s)
- Yair Yifrach
- Department of Physics, Ben-Gurion University of the Negev, Beer-Sheva 8410501, Israel
| | - Rami Rahimi
- Department of Physics, Ben-Gurion University of the Negev, Beer-Sheva 8410501, Israel
| | - Alexander Portnov
- Department of Physics, Ben-Gurion University of the Negev, Beer-Sheva 8410501, Israel
| | - Ilana Bar
- Department of Physics, Ben-Gurion University of the Negev, Beer-Sheva 8410501, Israel.
| |
Collapse
|
34
|
Margulis B, Narevicius J, Narevicius E. Direct observation of a Feshbach resonance by coincidence detection of ions and electrons in Penning ionization collisions. Nat Commun 2020; 11:3553. [PMID: 32678097 PMCID: PMC7366646 DOI: 10.1038/s41467-020-17393-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2020] [Accepted: 06/23/2020] [Indexed: 11/09/2022] Open
Abstract
Observation of molecular dynamics with quantum state resolution is one of the major challenges in chemical physics. Complete characterization of collision dynamics leads to the microscopic understanding and unraveling of different quantum phenomena such as scattering resonances. Here we present an experimental approach for observing molecular dynamics involving neutral particles and ions that is capable of providing state-to-state mapping of the dynamics. We use Penning ionization reaction between argon and metastable helium to generate argon ion and ground state helium atom pairs at separation of several angstroms. The energy of an ejected electron carries the information about the initial electronic state of an ion. The coincidence detection of ionic products provides a state resolved description of the post-ionization ion-neutral dynamics. We demonstrate that correlation between the electron and ion energy spectra enables us to directly observe the spin-orbit excited Feshbach resonance state of HeAr+. We measure the lifetime of the quasi-bound HeAr+ A2 state and discuss possible applications of our method.
Collapse
Affiliation(s)
- Baruch Margulis
- Department of Chemical and Biological Physics, Weizmann Institute of Science, Rehovot, Israel
| | - Julia Narevicius
- Department of Chemical and Biological Physics, Weizmann Institute of Science, Rehovot, Israel
| | - Edvardas Narevicius
- Department of Chemical and Biological Physics, Weizmann Institute of Science, Rehovot, Israel.
| |
Collapse
|
35
|
Baklanov AV, Parker DH. Weakly Bound Environment of Molecular Oxygen as a Catalyst of Photooxidation. KINETICS AND CATALYSIS 2020. [DOI: 10.1134/s0023158420020019] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
|
36
|
Liu Y, Grimes DD, Hu MG, Ni KK. Probing ultracold chemistry using ion spectrometry. Phys Chem Chem Phys 2020; 22:4861-4874. [DOI: 10.1039/c9cp07015j] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Reactions between KRb molecules at sub-microkelvin temperatures were probed using ion spectrometry.
Collapse
Affiliation(s)
- Yu Liu
- Department of Physics
- Harvard University
- Cambridge
- USA
- Department of Chemistry and Chemical Biology
| | - David D. Grimes
- Department of Physics
- Harvard University
- Cambridge
- USA
- Department of Chemistry and Chemical Biology
| | - Ming-Guang Hu
- Department of Physics
- Harvard University
- Cambridge
- USA
- Department of Chemistry and Chemical Biology
| | - Kang-Kuen Ni
- Department of Physics
- Harvard University
- Cambridge
- USA
- Department of Chemistry and Chemical Biology
| |
Collapse
|
37
|
Holt EL, Stavros VG. Applications of ultrafast spectroscopy to sunscreen development, from first principles to complex mixtures. INT REV PHYS CHEM 2019. [DOI: 10.1080/0144235x.2019.1663062] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Affiliation(s)
- Emily L. Holt
- Molecular Analytical Science Centre for Doctoral Training, Senate House, University of Warwick, Coventry, UK
- Department of Chemistry, University of Warwick, Coventry, UK
| | | |
Collapse
|
38
|
Falcinelli S, Rosi M, Pirani F, Bassi D, Alagia M, Schio L, Richter R, Stranges S, Balucani N, Lorent V, Vecchiocattivi F. Angular Distribution of Ion Products in the Double Photoionization of Propylene Oxide. Front Chem 2019; 7:621. [PMID: 31572712 PMCID: PMC6749015 DOI: 10.3389/fchem.2019.00621] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2019] [Accepted: 08/29/2019] [Indexed: 11/13/2022] Open
Abstract
A photoelectron-photoion-photoion coincidence technique, using an ion imaging detector and tunable synchrotron radiation in the 18.0–37.0 eV photon energy range, inducing the ejection of molecular valence electrons, has been applied to study the double ionization of the propylene oxide, a simple prototype chiral molecule. The experiment performed at the Elettra Synchrotron Facility (Trieste, Italy) allowed to determine angular distributions for ions produced by the two-body dissociation reactions following the Coulomb explosion of the intermediate (C3H6O)2+ molecular dication. The analysis of the coincidence spectra recorded at different photon energies was done in order to determine the dependence of the β anisotropy parameter on the photon energy for the investigated two-body fragmentation channels. In particular, the reaction leading to CH3+ + C2H3O+ appears to be characterized by an increase of β, from β ≈ 0.00 up to β = 0.59, as the photon energy increases from 29.7 to 37.0 eV, respectively. This new observation confirms that the dissociation channel producing CH3+ and C2H3O+ final ions can occur with two different microscopic mechanisms as already indicated by the bimodality obtained in the kinetic energy released (KER) distributions as a function of the photon energy in a recent study. Energetic considerations suggest that experimental data are compatible with the formation of two different stable isomers of C2H3O+: acetyl and oxiranyl cations. These new experimental data are inherently relevant and are mandatory information for further experimental and theoretical investigations involving oriented chiral molecules and linearly or circularly polarized radiation. This work is in progress in our laboratory.
Collapse
Affiliation(s)
- Stefano Falcinelli
- Department of Civil and Environmental Engineering, University of Perugia, Perugia, Italy
| | - Marzio Rosi
- Department of Civil and Environmental Engineering, University of Perugia, Perugia, Italy
| | - Fernando Pirani
- Department of Chemistry, Biology and Biotechnologies, University of Perugia, Perugia, Italy
| | - Davide Bassi
- Department of Physics, University of Trento, Trento, Italy
| | | | - Luca Schio
- IOM-CNR Tasc, Trieste, Italy.,Department of Basic and Applied Sciences for Engineering (SBAI), University of Rome "Sapienza", Rome, Italy
| | | | - Stefano Stranges
- IOM-CNR Tasc, Trieste, Italy.,Department of Chemistry and Drug Technologies, University of Rome "Sapienza", Rome, Italy
| | - Nadia Balucani
- Department of Chemistry, Biology and Biotechnologies, University of Perugia, Perugia, Italy
| | - Vincent Lorent
- Laboratoire de physique des lasers, Université Paris 13 (UP13) - Institut Galilée - CNRS LPL UMR7538, Villetaneuse, France
| | - Franco Vecchiocattivi
- Department of Civil and Environmental Engineering, University of Perugia, Perugia, Italy
| |
Collapse
|
39
|
Bianchini RH, Roman MJ, Costen ML, McKendrick KG. Real-space laser-induced fluorescence imaging applied to gas-liquid interfacial scattering. J Chem Phys 2019. [DOI: 10.1063/1.5110517] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Affiliation(s)
- Robert H. Bianchini
- Institute of Chemical Sciences, Heriot-Watt University, Edinburgh EH14 4AS, United Kingdom
| | - Maksymilian J. Roman
- Institute of Chemical Sciences, Heriot-Watt University, Edinburgh EH14 4AS, United Kingdom
| | - Matthew L. Costen
- Institute of Chemical Sciences, Heriot-Watt University, Edinburgh EH14 4AS, United Kingdom
| | - Kenneth G. McKendrick
- Institute of Chemical Sciences, Heriot-Watt University, Edinburgh EH14 4AS, United Kingdom
| |
Collapse
|
40
|
Bain M, Hansen CS, Karsili TNV, Ashfold MNR. Quantifying rival bond fission probabilities following photoexcitation: C-S bond fission in t-butylmethylsulfide. Chem Sci 2019; 10:5290-5298. [PMID: 31191885 PMCID: PMC6540878 DOI: 10.1039/c9sc00738e] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2019] [Accepted: 04/23/2019] [Indexed: 11/21/2022] Open
Abstract
We illustrate a new, collision-free experimental strategy that allows determination of the absolute probabilities of rival bond fission processes in a photoexcited molecule - here t-butylmethylsulfide (BSM). The method combines single photon ('universal') ionization laser probe methods, simultaneous imaging of all probed fragments (multi-mass ion imaging) and the use of an appropriate internal calibrant (here dimethylsulfide). Image analysis allows quantification of the dynamics of the rival B-SM and BS-M bond fission processes following ultraviolet (UV) excitation of BSM and shows the former to be twice as probable, despite the only modest (∼2%) differences in the respective ground state equilibrium C-S bond lengths or bond strengths. Rationalising this finding should provide a stringent test of the two close-lying, coupled excited states of 1A'' symmetry accessed by UV excitation in BSM and related thioethers, of the respective transition dipole moment surfaces, and of the geometry dependent non-adiabatic couplings that enable the rival C-S bond fissions.
Collapse
Affiliation(s)
- Matthew Bain
- School of Chemistry , University of Bristol , Bristol , BS8 1TS , UK .
| | - Christopher S Hansen
- School of Chemistry , University of New South Wales , Sydney , NSW 2052 , Australia .
| | - Tolga N V Karsili
- Department of Chemistry , University of Louisiana at Lafayette , Louisiana , LA 70504 , USA
| | | |
Collapse
|
41
|
Zhang B. Unraveling vibrational wavepacket dynamics using femtosecond ion yield spectroscopy and photoelectron imaging. CHINESE J CHEM PHYS 2019. [DOI: 10.1063/1674-0068/cjcp1811252] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Affiliation(s)
- Bing Zhang
- State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan 430071, China
| |
Collapse
|
42
|
Dick B. MELEXIR: maximum entropy Legendre expanded image reconstruction. A fast and efficient method for the analysis of velocity map imaging or photoelectron imaging data. Phys Chem Chem Phys 2019; 21:19499-19512. [DOI: 10.1039/c9cp03353j] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The MELEXIR program obtains a Legendre expansion of the 3D velocity distribution from 2D images of ions or photoelectrons. The maximum entropy algorithm avoids inverse Abel transforms, is fast and applicable to low-intensity images.
Collapse
Affiliation(s)
- Bernhard Dick
- Institut für Physikalische und Theoretische Chemie
- Universität Regensburg
- 93053 Regensburg
- Germany
| |
Collapse
|
43
|
Vallance C. Multi-mass velocity-map imaging studies of photoinduced and electron-induced chemistry. Chem Commun (Camb) 2019; 55:6336-6352. [PMID: 31099379 DOI: 10.1039/c9cc02426c] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Multi-mass velocity-map imaging (VMI) is becoming established as a promising method for probing the dynamics of a variety of gas-phase chemical processes. We provide an overview of velocity-map imaging and multi-mass velocity-map imaging techniques, highlighting examples in which these approaches have been used to provide mechanistic insights into a range of photoinduced and electron-induced chemical processes. Multi-mass detection capabilities have also led to the development of two new tools for the chemical dynamics toolbox, in the form of Coulomb-explosion imaging and covariance-map imaging. These allow details of molecular structure to be followed in real time over the course of a chemical reaction, offering the tantalising prospect of recording real-time 'molecular movies' of chemical dynamics. As these new methods become established within the reaction dynamics community, they promise new mechanistic insights into chemistry relevant to fields ranging from atmospheric chemistry and astrochemistry through to synthetic organic photochemistry and biology.
Collapse
Affiliation(s)
- Claire Vallance
- Department of Chemistry, University of Oxford, Chemistry Research Laboratory, 12 Mansfield Rd, Oxford OX1 3TA, UK.
| |
Collapse
|
44
|
Johnston MD, Gentry MR, Metz RB. Photofragment Imaging, Spectroscopy, and Theory of MnO . J Phys Chem A 2018; 122:8047-8053. [PMID: 30226771 DOI: 10.1021/acs.jpca.8b07849] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Density functional and ab initio calculations, along with photodissociation spectroscopy and ion imaging of MnO+ from 21,300 to 33,900 cm-1, are used to probe the photodissociation dynamics and bond strength of the manganese oxide cation (MnO+). These studies confirm the theoretical ground state (5Π) and determine the spin-orbit constant ( A' = 14 cm-1) of the dominant optically accessible excited state (5Π) in the region. Photodissociation via this excited 5Π state results in ground state Mn+ (7S) + O (3P) products. At energies above 30,000 cm-1, the Mn+ (5S) + O (3P) channel is energetically accessible and becomes the preferred dissociation pathway. The bond dissociation energy ( D0 = 242 ± 5 kJ/mol) of MnO+ is measured from several images of each photofragmentation channel and compared to theory, resolving a disagreement in previous measurements. MRCI+Q calculations are much more successful in predicting the observed spectrum than TD-DFT or EOM-CCSD calculations.
Collapse
Affiliation(s)
- M David Johnston
- Department of Chemistry , University of Massachusetts Amherst , Amherst , Massachusetts 01003 , United States
| | - Matthew R Gentry
- Department of Chemistry , University of Massachusetts Amherst , Amherst , Massachusetts 01003 , United States
| | - Ricardo B Metz
- Department of Chemistry , University of Massachusetts Amherst , Amherst , Massachusetts 01003 , United States
| |
Collapse
|
45
|
Bain M, Hansen CS, Ashfold MNR. Communication: Multi-mass velocity map imaging study of the ultraviolet photodissociation of dimethyl sulfide using single photon ionization and a PImMS2 sensor. J Chem Phys 2018; 149:081103. [DOI: 10.1063/1.5048838] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Matthew Bain
- School of Chemistry, University of Bristol, Cantock’s Close, Bristol BS8 1TS, United Kingdom
| | | | - Michael N. R. Ashfold
- School of Chemistry, University of Bristol, Cantock’s Close, Bristol BS8 1TS, United Kingdom
| |
Collapse
|
46
|
Cheng BM, Grover JR, Walters EA, Clay JT. Kinetic energy release distributions from dissociative photoionization of weakly bound trimers at 14-27 eV. Phys Chem Chem Phys 2018; 20:21034-21042. [PMID: 30073227 DOI: 10.1039/c8cp03013h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The formation of the intriguing ions C4H6O+, C6H6Cl+, and C6H6O+, by dissociative ionization of heterotrimers of butadiene/sulfur dioxide, benzene/hydrogen chloride and benzene/oxygen by 14-27 eV photons, illustrates the possibility that VUV irradiation of clusters comprised of three or more molecules could provide a route to make ions containing bonds not previously accessible. Kinetic energy release distributions were measured in an attempt to understand the formation of these ions and why clusters larger than dimers are needed. Standard theory was applied to find whether more complicated theoretical treatments are needed to understand the data. It was found that all of the above ions were most likely produced by essentially the same mechanism: excitation of one moiety, transfer of its excitation energy to the moiety that dissociates, followed by slow decay of the remaining excited ion into the unexcited moiety as the "solvent" plus the ion with the new bond. The very low reaction probabilities to produce these ions, combined with very low target densities in the presence of many orders of magnitude higher densities of other molecules, precluded the usual imaging techniques. However, we found that the retarding-potential method can give useful data. Also, at present laser photon energies higher than 15 eV provide significantly smaller average intensities than are needed.
Collapse
Affiliation(s)
- Bing-Ming Cheng
- National Synchrotron Radiation Research Center, 101 Hsin-Ann Road, Hsinchu Science Park, Hsinchu 30076, Taiwan.
| | | | | | | |
Collapse
|
47
|
Multidimensional Analysis of Time-Resolved Charged Particle Imaging Experiments. APPLIED SCIENCES-BASEL 2018. [DOI: 10.3390/app8081227] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
We present a tutorial to realize a multidimensional fitting procedure capable of extracting all the relevant information contained in a sequence of charged particle images acquired as a function of time in femtosecond pump–probe experiments. The images are reproduced using a 3D fitting method, which provides the velocity (or center-of-mass kinetic energy) and angular distributions contained in the images and their time evolution. A detailed example of the method is shown through the analysis of the time-resolved predissociation dynamics of CH3I on the B-band origin (Gitzinger et al., J. Chem. Phys.2010, 133, 234313). We show that the multidimensional approach is essential for the analysis of complex images that contain several overlapping contributions where reduced dimensionality analyses cannot provide a reliable description of the features present in the image sequence. This methodology can be generalized to many types of multidimensional data analysis.
Collapse
|
48
|
Jambrina PG, Menéndez M, Aoiz FJ. Angular momentum-scattering angle quantum correlation: a generalized deflection function. Chem Sci 2018; 9:4837-4850. [PMID: 29910936 PMCID: PMC5982215 DOI: 10.1039/c7sc05489k] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2017] [Accepted: 04/25/2018] [Indexed: 11/23/2022] Open
Abstract
A natural generalization of the classical deflection function, the functional dependence of the deflection angle on the angular momentum (or the impact parameter), is the joint probability density function of these two quantities, revealing the correlation between them. It provides, at a glance, detailed information about the reaction mechanisms and how changes in the impact parameter affect the product angular distribution. It is also useful to predict the presence of quantum phenomena such as interference. However, the classical angular momentum-scattering angle correlation function has a limited use whenever quantum effects become important. Rigorously speaking, there is not a quantum equivalent of the classical joint distribution, as the differential cross section depends on the coherences between the different values of J caused by the cross terms in the expansion of partial waves. In this article, we present a simple method to calculate a quantum analog of this correlation, a generalized deflection function that can shed light onto the reaction mechanism using just quantum mechanical results. Our results show that there is a very good agreement between the quantum and classical correlation functions as long as quantum effects are not all relevant. When this is not the case, it will also be shown that the quantum correlation function is most useful to observe the extent of quantum effects such as interference among different reaction mechanisms.
Collapse
Affiliation(s)
- P G Jambrina
- Departamento de Química Física Aplicada , Universidad Autonoma de Madrid , 28049 , Madrid , Spain .
| | - M Menéndez
- Departamento de Química Física I , Facultad de Ciencias Químicas , Universidad Complutense de Madrid , 28040 Madrid , Spain .
| | - F J Aoiz
- Departamento de Química Física I , Facultad de Ciencias Químicas , Universidad Complutense de Madrid , 28040 Madrid , Spain .
| |
Collapse
|
49
|
Long J, Furch FJ, Durá J, Tremsin AS, Vallerga J, Schulz CP, Rouzée A, Vrakking MJJ. Ion-ion coincidence imaging at high event rate using an in-vacuum pixel detector. J Chem Phys 2018; 147:013919. [PMID: 28688405 DOI: 10.1063/1.4981126] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
A new ion-ion coincidence imaging spectrometer based on a pixelated complementary metal-oxide-semiconductor detector has been developed for the investigation of molecular ionization and fragmentation processes in strong laser fields. Used as a part of a velocity map imaging spectrometer, the detection system is comprised of a set of microchannel plates and a Timepix detector. A fast time-to-digital converter (TDC) is used to enhance the ion time-of-flight resolution by correlating timestamps registered separately by the Timepix detector and the TDC. In addition, sub-pixel spatial resolution (<6 μm) is achieved by the use of a center-of-mass centroiding algorithm. This performance is achieved while retaining a high event rate (104 per s). The spectrometer was characterized and used in a proof-of-principle experiment on strong field dissociative double ionization of carbon dioxide molecules (CO2), using a 400 kHz repetition rate laser system. The experimental results demonstrate that the spectrometer can detect multiple ions in coincidence, making it a valuable tool for studying the fragmentation dynamics of molecules in strong laser fields.
Collapse
Affiliation(s)
- Jingming Long
- Max-Born-Institut für Nichtlineare Optik und Kurzzeitspektroskopie, Max-Born-Straße 2A, 12489 Berlin, Germany
| | - Federico J Furch
- Max-Born-Institut für Nichtlineare Optik und Kurzzeitspektroskopie, Max-Born-Straße 2A, 12489 Berlin, Germany
| | - Judith Durá
- Max-Born-Institut für Nichtlineare Optik und Kurzzeitspektroskopie, Max-Born-Straße 2A, 12489 Berlin, Germany
| | - Anton S Tremsin
- The Space Sciences Laboratory, University of California, Berkeley, California 94720, USA
| | - John Vallerga
- The Space Sciences Laboratory, University of California, Berkeley, California 94720, USA
| | - Claus Peter Schulz
- Max-Born-Institut für Nichtlineare Optik und Kurzzeitspektroskopie, Max-Born-Straße 2A, 12489 Berlin, Germany
| | - Arnaud Rouzée
- Max-Born-Institut für Nichtlineare Optik und Kurzzeitspektroskopie, Max-Born-Straße 2A, 12489 Berlin, Germany
| | - Marc J J Vrakking
- Max-Born-Institut für Nichtlineare Optik und Kurzzeitspektroskopie, Max-Born-Straße 2A, 12489 Berlin, Germany
| |
Collapse
|
50
|
Grygoryeva K, Rakovský J, Votava O, Fárník M. Imaging of rotational wave-function in photodissociation of rovibrationally excited HCl molecules. J Chem Phys 2018; 147:013901. [PMID: 28688430 DOI: 10.1063/1.4973680] [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 demonstrate a visualization of quantum mechanical phenomena with the velocity map imaging (VMI) technique, combining vibrationally mediated photodissociation (VMP) of a simple diatomic HCl with the VMI of its H-photofragments. Free HCl molecules were excited by a pump infrared (IR) laser pulse to particular rotational J levels of the v = 2 vibrational state, and subsequently a probe ultraviolet laser photodissociated the molecule at a fixed wavelength of 243.07 nm where also the H-fragments were ionized. The molecule was aligned by the IR excitation with respect to the IR laser polarization, and this alignment was reflected in the angular distribution of the H-photofragments. In particular, the highest degree of molecular alignment was achieved for the J=1←0 transition, which exclusively led to the population of a single rotational state with M = 0. The obtained images were analyzed for further details of the VMP dynamics, and different J states were studied as well. Additionally, we investigated the dynamic evolution of the excited states by changing the pump-probe laser pulse delay; the corresponding images reflected dephasing due to a coupling between the molecular angular momentum and nuclear spin. Our measurements confirmed previous observation using the time-of-flight technique by Sofikitis et al. [J. Chem. Phys. 127, 144307 (2007)]. We observed a partial recovery of the originally excited state after 60 ns in agreement with the previous observation.
Collapse
Affiliation(s)
- K Grygoryeva
- J. Heyrovský Institute of Physical Chemistry v.v.i., Academy of Sciences of the Czech Republic, Dolejškova 3, 18223 Prague, Czech Republic
| | - J Rakovský
- J. Heyrovský Institute of Physical Chemistry v.v.i., Academy of Sciences of the Czech Republic, Dolejškova 3, 18223 Prague, Czech Republic
| | - O Votava
- J. Heyrovský Institute of Physical Chemistry v.v.i., Academy of Sciences of the Czech Republic, Dolejškova 3, 18223 Prague, Czech Republic
| | - M Fárník
- J. Heyrovský Institute of Physical Chemistry v.v.i., Academy of Sciences of the Czech Republic, Dolejškova 3, 18223 Prague, Czech Republic
| |
Collapse
|