1
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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.
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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
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2
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Falcinelli S, Vecchiocattivi F, Pirani F. The topology of the reaction stereo-dynamics in chemi-ionizations. Commun Chem 2023; 6:30. [PMID: 36782019 PMCID: PMC9925729 DOI: 10.1038/s42004-023-00830-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2022] [Accepted: 02/03/2023] [Indexed: 02/15/2023] Open
Abstract
Details on the stereo-dynamic topology of chemi-ionizations highlight the role of the centrifugal barrier of colliding reactants: it acts as a selector of the orbital quantum number effective for reaction in a state-to-state treatment. Here, an accurate internally consistent formulation of the Optical interaction potentials, obtained by the combined analysis of scattering and spectroscopic experimental findings, casts light on structure, energy and angular momentum couplings of the precursor (pre-reactive) state controlling the stereo-dynamics of prototypical chemi-ionization reactions. The closest approach (turning point) of reagents, is found to control the relative weight of two different reaction mechanisms: (i) A direct mechanism stimulated by exchange chemical forces mainly acting at short separation distances and high collision energy; (ii) An indirect mechanism, caused by the combination of weak chemical and physical forces dominant at larger distances, mainly probed at low collision energy, that can be triggered by a virtual photon exchange between reagents.
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Affiliation(s)
- Stefano Falcinelli
- Department of Civil and Environmental Engineering, University of Perugia, Via G. Duranti 93, 06125, Perugia, Italy.
| | - Franco Vecchiocattivi
- grid.9027.c0000 0004 1757 3630Department of Civil and Environmental Engineering, University of Perugia, Via G. Duranti 93, 06125 Perugia, Italy
| | - Fernando Pirani
- grid.9027.c0000 0004 1757 3630Department of Civil and Environmental Engineering, University of Perugia, Via G. Duranti 93, 06125 Perugia, Italy ,grid.9027.c0000 0004 1757 3630Department of Chemistry, Biology and Biotechnologies, University of Perugia, Via Elce di Sotto 8, 06123 Perugia, Italy
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3
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Perreault WE, Zhou H, Mukherjee N, Zare RN. Quantum Controlled Cold Scattering Challenges Theory. J Phys Chem Lett 2022; 13:10912-10917. [PMID: 36394562 DOI: 10.1021/acs.jpclett.2c03038] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
Our previous rotationally inelastic cold scattering experiments between state prepared D2 (v = 2, j = 2, m = 0) and He disagreed with theory, raising serious concerns about either our understanding of the anisotropic potential or the accuracy of the measurement. To further interrogate interactions between molecular hydrogen and atomic helium, we study the Δj = 1and Δj = 2 rotational relaxation of HD (v = 2, j = 2, m = 0) by collision with He. The two rotational transitions probe different anisotropic components of the van der Waals potential. Our state resolved scattering study shows that these two transitions are mediated by two different shape resonances l = 1 for Δj = 1 and l = 2 for Δj = 2. The strong l = 1 resonance dominates the Δj = 1 scattering, agreeing with theory. However, the dominance of the weaker l = 2 resonance in the Δj = 2 transition, which matches our earlier D2-He result, contradicts theoretical calculations. The continued contradiction, when we expect one-to-one correspondence between our stereodynamically controlled scattering experiment and theoretical calculations, makes us question the accuracy of the weaker anisotropic part of the H2-He interaction potential.
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Affiliation(s)
- William E Perreault
- Department of Chemistry, Stanford University, Stanford, California94305, United States
| | - Haowen Zhou
- Department of Chemistry, Stanford University, Stanford, California94305, United States
| | - Nandini Mukherjee
- Department of Chemistry, Stanford University, Stanford, California94305, United States
| | - Richard N Zare
- Department of Chemistry, Stanford University, Stanford, California94305, United States
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4
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Zhou H, Perreault WE, Mukherjee N, Zare RN. Anisotropic dynamics of resonant scattering between a pair of cold aligned diatoms. Nat Chem 2022; 14:658-663. [PMID: 35501483 DOI: 10.1038/s41557-022-00926-z] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2021] [Accepted: 03/09/2022] [Indexed: 11/09/2022]
Abstract
The collision dynamics between a pair of aligned molecules in the presence of a partial-wave resonance provide the most sensitive probe of the long-range anisotropic forces important to chemical reactions. Here we control the collision temperature and geometry to probe the dynamics of cold (1-3 K) rotationally inelastic scattering of a pair of optically state-prepared D2 molecules. The collision temperature is manipulated by combining the gating action of laser state preparation and detection with the velocity dispersion of the molecular beam. When the bond axes of both molecules are aligned parallel to the collision velocity, the scattering rate drops by a factor of 3.5 as collision energies >2.1 K are removed, suggesting a geometry-dependent resonance. Partial-wave analysis of the measured angular distribution supports a shape resonance within the centrifugal barrier of the l = 2 incoming orbital. Our experiment illustrates the strong anisotropy of the quadrupole-quadrupole interaction that controls the dynamics of resonant scattering.
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Affiliation(s)
- Haowen Zhou
- Department of Chemistry, Stanford University, Stanford, CA, USA
| | | | | | - Richard N Zare
- Department of Chemistry, Stanford University, Stanford, CA, USA.
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5
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Sixt T, Stienkemeier F, Dulitz K. Spin-state-controlled chemi-ionization reactions between metastable helium atoms and ground-state lithium atoms. J Chem Phys 2022; 156:114306. [DOI: 10.1063/5.0083842] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
We demonstrate the control of 4He(23S1)–7Li(22S1/2) chemi-ionization reactions by all-optical electron-spin-state preparation of both atomic species prior to the collision process. Our results demonstrate that chemi-ionization is strongly suppressed (enhanced) for non-spin-conserving (spin-conserving) collisions at thermal energies. These findings are in good agreement with a model based on spin angular momentum coupling of the prepared atomic states to the quasi-molecular states. Small deviations from the model indicate the contribution of the 4Σ+ channel to the reaction rate, which is in violation of spin conservation.
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Affiliation(s)
- Tobias Sixt
- Institute of Physics, University of Freiburg, Hermann-Herder-Str. 3, 79104 Freiburg, Germany
| | - Frank Stienkemeier
- Institute of Physics, University of Freiburg, Hermann-Herder-Str. 3, 79104 Freiburg, Germany
| | - Katrin Dulitz
- Institute of Physics, University of Freiburg, Hermann-Herder-Str. 3, 79104 Freiburg, Germany
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6
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Mapping partial wave dynamics in scattering resonances by rotational de-excitation collisions. Nat Chem 2022; 14:538-544. [PMID: 35210587 DOI: 10.1038/s41557-022-00896-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2021] [Accepted: 01/21/2022] [Indexed: 11/09/2022]
Abstract
One of the most important parameters in a collision is the 'miss distance' or impact parameter, which in quantum mechanics is described by quantized partial waves. Usually, the collision outcome is the result of unavoidable averaging over many partial waves. Here we present a study of low-energy NO-He collisions that enables us to probe how individual partial waves evolve during the collision. By tuning the collision energies to scattering resonances between 0.4 and 6 cm-1, the initial conditions are characterized by a limited set of partial waves. By preparing NO in a rotationally excited state before the collision and by studying rotational de-excitation collisions, we were able to add one quantum of angular momentum to the system and trace how it evolves. Distinct fingerprints in the differential cross-sections yield a comprehensive picture of the partial wave dynamics during the scattering process. Exploiting the principle of detailed balance, we show that rotational de-excitation collisions probe time-reversed excitation processes with superior energy and angular resolution.
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7
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Luski A, Segev Y, David R, Bitton O, Nadler H, Barnea AR, Gorlach A, Cheshnovsky O, Kaminer I, Narevicius E. Vortex beams of atoms and molecules. Science 2021; 373:1105-1109. [PMID: 34516841 DOI: 10.1126/science.abj2451] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
[Figure: see text].
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Affiliation(s)
- Alon Luski
- Faculty of Chemistry, Weizmann Institute of Science, Rehovot, Israel
| | - Yair Segev
- Faculty of Chemistry, Weizmann Institute of Science, Rehovot, Israel
| | - Rea David
- Faculty of Chemistry, Weizmann Institute of Science, Rehovot, Israel
| | - Ora Bitton
- Faculty of Chemistry, Weizmann Institute of Science, Rehovot, Israel
| | - Hila Nadler
- Faculty of Chemistry, Weizmann Institute of Science, Rehovot, Israel
| | - A Ronny Barnea
- School of Chemistry, Sackler Faculty of Exact Sciences, Tel Aviv University, Tel Aviv, Israel
| | - Alexey Gorlach
- Department of Electrical and Computer Engineering, Technion - Israel Institute of Technology, Haifa, Israel
| | - Ori Cheshnovsky
- School of Chemistry, Sackler Faculty of Exact Sciences, Tel Aviv University, Tel Aviv, Israel
| | - Ido Kaminer
- Department of Electrical and Computer Engineering, Technion - Israel Institute of Technology, Haifa, Israel
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8
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Jurgilas S, Chakraborty A, Rich CJH, Caldwell L, Williams HJ, Fitch NJ, Sauer BE, Frye MD, Hutson JM, Tarbutt MR. Collisions between Ultracold Molecules and Atoms in a Magnetic Trap. PHYSICAL REVIEW LETTERS 2021; 126:153401. [PMID: 33929220 DOI: 10.1103/physrevlett.126.153401] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/05/2021] [Revised: 02/19/2021] [Accepted: 03/04/2021] [Indexed: 06/12/2023]
Abstract
We prepare mixtures of ultracold CaF molecules and Rb atoms in a magnetic trap and study their inelastic collisions. When the atoms are prepared in the spin-stretched state and the molecules in the spin-stretched component of the first rotationally excited state, they collide inelastically with a rate coefficient k_{2}=(6.6±1.5)×10^{-11} cm^{3}/s at temperatures near 100 μK. We attribute this to rotation-changing collisions. When the molecules are in the ground rotational state we see no inelastic loss and set an upper bound on the spin-relaxation rate coefficient of k_{2}<5.8×10^{-12} cm^{3}/s with 95% confidence. We compare these measurements to the results of a single-channel loss model based on quantum defect theory. The comparison suggests a short-range loss parameter close to unity for rotationally excited molecules, but below 0.04 for molecules in the rotational ground state.
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Affiliation(s)
- S Jurgilas
- Centre for Cold Matter, Blackett Laboratory, Imperial College London, Prince Consort Road, London SW7 2AZ, United Kingdom
| | - A Chakraborty
- Centre for Cold Matter, Blackett Laboratory, Imperial College London, Prince Consort Road, London SW7 2AZ, United Kingdom
| | - C J H Rich
- Centre for Cold Matter, Blackett Laboratory, Imperial College London, Prince Consort Road, London SW7 2AZ, United Kingdom
| | - L Caldwell
- Centre for Cold Matter, Blackett Laboratory, Imperial College London, Prince Consort Road, London SW7 2AZ, United Kingdom
| | - H J Williams
- Centre for Cold Matter, Blackett Laboratory, Imperial College London, Prince Consort Road, London SW7 2AZ, United Kingdom
| | - N J Fitch
- Centre for Cold Matter, Blackett Laboratory, Imperial College London, Prince Consort Road, London SW7 2AZ, United Kingdom
| | - B E Sauer
- Centre for Cold Matter, Blackett Laboratory, Imperial College London, Prince Consort Road, London SW7 2AZ, United Kingdom
| | - Matthew D Frye
- Joint Quantum Centre (JQC) Durham-Newcastle, Department of Chemistry, Durham University, South Road, Durham DH1 3LE, United Kingdom
| | - Jeremy M Hutson
- Joint Quantum Centre (JQC) Durham-Newcastle, Department of Chemistry, Durham University, South Road, Durham DH1 3LE, United Kingdom
| | - M R Tarbutt
- Centre for Cold Matter, Blackett Laboratory, Imperial College London, Prince Consort Road, London SW7 2AZ, United Kingdom
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9
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Madajczyk K, Żuchowski PS, Brzȩk F, Rajchel Ł, Kȩdziera D, Modrzejewski M, Hapka M. Dataset of noncovalent intermolecular interaction energy curves for 24 small high-spin open-shell dimers. J Chem Phys 2021; 154:134106. [PMID: 33832261 DOI: 10.1063/5.0043793] [Citation(s) in RCA: 3] [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 introduce a dataset of 24 interaction energy curves of open-shell noncovalent dimers, referred to as the O24 × 5 dataset. The dataset consists of high-spin dimers up to 11 atoms selected to assure diversity with respect to interaction types: dispersion, electrostatics, and induction. The benchmark interaction energies are obtained at the restricted open-shell CCSD(T) level of theory with complete basis set extrapolation (from aug-cc-pVQZ to aug-cc-pV5Z). We have analyzed the performance of selected wave function methods MP2, CCSD, and CCSD(T) as well as the F12a and F12b variants of coupled-cluster theory. In addition, we have tested dispersion-corrected density functional theory methods based on the PBE exchange-correlation model. The O24 × 5 dataset is a challenge to approximate methods due to the wide range of interaction energy strengths it spans. For the dispersion-dominated and mixed-type subsets, any tested method that does not include the triples contribution yields errors on the order of tens of percent. The electrostatic subset is less demanding with errors that are typically an order of magnitude smaller than the mixed and dispersion-dominated subsets.
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Affiliation(s)
- Katarzyna Madajczyk
- Institute of Physics, Faculty of Physics, Astronomy and Informatics, Nicolaus Copernicus University, ul. Grudzia̧dzka 5, 87-100 Toruń, Poland
| | - Piotr S Żuchowski
- Institute of Physics, Faculty of Physics, Astronomy and Informatics, Nicolaus Copernicus University, ul. Grudzia̧dzka 5, 87-100 Toruń, Poland
| | - Filip Brzȩk
- Institute of Physics, Faculty of Physics, Astronomy and Informatics, Nicolaus Copernicus University, ul. Grudzia̧dzka 5, 87-100 Toruń, Poland
| | - Łukasz Rajchel
- Institute of Physics, Faculty of Physics, Astronomy and Informatics, Nicolaus Copernicus University, ul. Grudzia̧dzka 5, 87-100 Toruń, Poland
| | - Dariusz Kȩdziera
- Faculty of Chemistry, Nicolaus Copernicus University, ul. Gagarina 7, Toruń, Poland
| | - Marcin Modrzejewski
- Faculty of Chemistry, University of Warsaw, ul. L. Pasteura 1, 02-093 Warsaw, Poland
| | - Michał Hapka
- Faculty of Chemistry, University of Warsaw, ul. L. Pasteura 1, 02-093 Warsaw, Poland
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10
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Sáez-Rábanos V, Verdasco JE, Aoiz FJ, Herrero VJ. The F + HD(v = 0, 1; j = 0, 1) reactions: stereodynamical properties of orbiting resonances. Phys Chem Chem Phys 2021; 23:8002-8012. [PMID: 33480905 DOI: 10.1039/d0cp05425a] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The excitation functions (reaction cross-section as a function of collision energy) of the F + HD(v = 0, 1; j = 0, 1) benchmark system have been calculated in the 0.01-6 meV collision energy interval using a time-independent hyperspherical quantum dynamics methodology. Special attention has been paid to orbiting resonances, which bring about detailed information on the three-atom interaction during the reactive encounter. The location of the resonances depends on the rovibrational state of the reactants HD(v,j), but is the same for the two product channels HF + D and DF + H, as expected for these resonances that are linked to the van der Waals well at the entrance. The resonance intensities depend both on the entrance and on the exit channels. The peak intensities for the HF + D channel are systematically larger than those for DF + H. Vibrational excitation leads to an increase of the peak intensity by more than an order of magnitude, but rotational excitation has a less drastic effect. It deceases the resonance intensity of the F + HD(v = 1) reaction, but increases somewhat that of F + HD(v = 0). Polarization of the rotational angular momentum with respect to the initial velocity reveals intrinsic directional preferences in the F + HD(v = 0, 1; j = 1) reactions that are manifested in the resonance patterns. The helicities (Ω = 0, Ω = ±1) possible for j = 1 contribute to the resonances, but that from Ω± 1 is, in general, dominant and in some cases exclusive. It corresponds to a preferential alignment of the HD internuclear axis perpendicular to the initial direction of approach and, thus, to side-on collisions. This work also shows that external preparation of the reactants, following the intrinsic preferences, would allow the enhancement or reduction of specific resonance features, and would be of great help for their eventual experimental detection.
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Affiliation(s)
- V Sáez-Rábanos
- Departamento de Sistemas y Recursos Naturales, E.T.S. de Ingeniería de Montes, Forestal y del Medio Natural, Universidad Politécnica de Madrid, 28040, Madrid, Spain.
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11
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Shuai Q, de Jongh T, Besemer M, van der Avoird A, Groenenboom GC, van de Meerakker SYT. Experimental and theoretical investigation of resonances in low-energy NO-H 2 collisions. J Chem Phys 2020; 153:244302. [PMID: 33380097 DOI: 10.1063/5.0033488] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The experimental characterization of scattering resonances in low energy collisions has proven to be a stringent test for quantum chemistry calculations. Previous measurements on the NO-H2 system at energies down to 10 cm-1 challenged the most sophisticated calculations of potential energy surfaces available. In this report, we continue these investigations by measuring the scattering behavior of the NO-H2 system in the previously unexplored 0.4 cm-1-10 cm-1 region for the parity changing de-excitation channel of NO. We study state-specific inelastic collisions with both para- and ortho-H2 in a crossed molecular beam experiment involving Stark deceleration and velocity map imaging. We are able to resolve resonance features in the measured integral and differential cross sections. Results are compared to predictions from two previously available potential energy surfaces, and we are able to clearly discriminate between the two potentials. We furthermore identify the partial wave contributions to these resonances and investigate the nature of the differences between collisions with para- and ortho-H2. Additionally, we tune the energy spreads in the experiment to our advantage to probe scattering behavior at energies beyond our mean experimental limit.
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Affiliation(s)
- Quan Shuai
- Radboud University, Institute for Molecules and Materials, Heijendaalseweg 135, 6525 AJ Nijmegen, The Netherlands
| | - Tim de Jongh
- Radboud University, Institute for Molecules and Materials, Heijendaalseweg 135, 6525 AJ Nijmegen, The Netherlands
| | - Matthieu Besemer
- Radboud University, Institute for Molecules and Materials, Heijendaalseweg 135, 6525 AJ Nijmegen, The Netherlands
| | - Ad van der Avoird
- Radboud University, Institute for Molecules and Materials, Heijendaalseweg 135, 6525 AJ Nijmegen, The Netherlands
| | - Gerrit C Groenenboom
- Radboud University, Institute for Molecules and Materials, Heijendaalseweg 135, 6525 AJ Nijmegen, The Netherlands
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12
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Jansen P, Merkt F. Manipulating beams of paramagnetic atoms and molecules using inhomogeneous magnetic fields. PROGRESS IN NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY 2020; 120-121:118-148. [PMID: 33198967 DOI: 10.1016/j.pnmrs.2020.08.002] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/29/2020] [Revised: 08/07/2020] [Accepted: 08/10/2020] [Indexed: 06/11/2023]
Abstract
We review methods to manipulate the motion of pulsed supersonic atomic and molecular beams using time-independent and -dependent inhomogeneous magnetic fields. In addition, we discuss current and possible future applications and research directions.
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Affiliation(s)
- Paul Jansen
- Laboratory of Physical Chemistry, ETH Zurich, CH-8093 Zurich, Switzerland.
| | - Frédéric Merkt
- Laboratory of Physical Chemistry, ETH Zurich, CH-8093 Zurich, Switzerland
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13
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de Jongh T, Besemer M, Shuai Q, Karman T, van der Avoird A, Groenenboom GC, van de Meerakker SYT. Imaging the onset of the resonance regime in low-energy NO-He collisions. Science 2020; 368:626-630. [DOI: 10.1126/science.aba3990] [Citation(s) in RCA: 50] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2019] [Accepted: 03/19/2020] [Indexed: 11/02/2022]
Affiliation(s)
- Tim de Jongh
- Institute for Molecules and Materials, Radboud University, 6525 AJ Nijmegen, Netherlands
| | - Matthieu Besemer
- Institute for Molecules and Materials, Radboud University, 6525 AJ Nijmegen, Netherlands
| | - Quan Shuai
- Institute for Molecules and Materials, Radboud University, 6525 AJ Nijmegen, Netherlands
| | - Tijs Karman
- Institute for Theoretical Atomic Molecular and Optical Physics, Center For Astrophysics, Harvard and Smithsonian, Cambridge, MA 02138, USA
| | - Ad van der Avoird
- Institute for Molecules and Materials, Radboud University, 6525 AJ Nijmegen, Netherlands
| | - Gerrit C. Groenenboom
- Institute for Molecules and Materials, Radboud University, 6525 AJ Nijmegen, Netherlands
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14
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Dulitz K, van den Beld-Serrano M, Stienkemeier F. Single-Source, Collinear Merged-Beam Experiment for the Study of Reactive Neutral–Neutral Collisions. J Phys Chem A 2020; 124:3484-3493. [DOI: 10.1021/acs.jpca.0c00608] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Katrin Dulitz
- Institute of Physics, University of Freiburg, Hermann-Herder-Str. 3, 79104 Freiburg, Germany
| | | | - Frank Stienkemeier
- Institute of Physics, University of Freiburg, Hermann-Herder-Str. 3, 79104 Freiburg, Germany
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15
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Pawlak M, Żuchowski PS, Moiseyev N, Jankowski P. Evidence of Nonrigidity Effects in the Description of Low-Energy Anisotropic Molecular Collisions of Hydrogen Molecules with Excited Metastable Helium Atoms. J Chem Theory Comput 2020; 16:2450-2459. [PMID: 32150402 PMCID: PMC7497643 DOI: 10.1021/acs.jctc.0c00183] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
![]()
Cold collisions serve
as a sensitive probe of the interaction potential.
In the recent study of Klein et al. (Nature Phys.2017, 13, 35–38), the one-parameter
scaling of the interaction potential was necessary to obtain agreement
between theoretical and observed patterns of the orbiting resonances
for excited metastable helium atoms colliding with hydrogen molecules.
Here, we show that the effect of nonrigidity of the H2 molecule
on the resonant structure, absent in the previous study, is critical
to predict the correct positions of the resonances in that case. We
have complemented the theoretical description of the interaction potential
and revised reaction rate coefficients by proper inclusion of the
flexibility of the molecule. The calculated reaction rate coefficients
are in remarkable agreement with the experimental data without empirical
adjustment of the interaction potential. We have shown that even state-of-the-art
calculations of the interaction energy cannot ensure agreement with
the experiment if such an important physical effect as flexibility
of the interacting molecule is neglected. Our findings about the significance
of the nonrigidity effects can be especially crucial in cold chemistry,
where the quantum nature of molecules is pronounced.
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Affiliation(s)
- Mariusz Pawlak
- Faculty of Chemistry, Nicolaus Copernicus University in Toruń, Gagarina 7, 87-100 Toruń, Poland
| | - Piotr S Żuchowski
- Faculty of Physics, Astronomy and Informatics, Nicolaus Copernicus University in Toruń, Grudziądzka 5, 87-100 Toruń, Poland
| | - Nimrod Moiseyev
- Schulich Faculty of Chemistry and Department of Physics, Technion-Israel Institute of Technology, Haifa 32000, Israel
| | - Piotr Jankowski
- Faculty of Chemistry, Nicolaus Copernicus University in Toruń, Gagarina 7, 87-100 Toruń, Poland
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16
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Affiliation(s)
- Sean D. S. Gordon
- Institute for Chemical Sciences and Engineering (ISIC), Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
- Present address: EPFL Innovation Park, Building C, 1015 Lausanne, Switzerland
| | - Andreas Osterwalder
- Institute for Chemical Sciences and Engineering (ISIC), Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
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17
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Li H, Suits AG. Universal crossed beam imaging studies of polyatomic reaction dynamics. Phys Chem Chem Phys 2020; 22:11126-11138. [DOI: 10.1039/d0cp00522c] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Crossed-beam imaging studies of polyatomic reactions show surprising dynamics not anticipated by extrapolation from smaller model systems.
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Affiliation(s)
- Hongwei Li
- Department of Chemistry
- University of Missouri
- Columbia
- USA
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18
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Sáez-Rábanos V, Verdasco JE, Herrero VJ. Orbiting resonances in the F + HD (v = 0, 1) reaction at very low collision energies. A quantum dynamical study. Phys Chem Chem Phys 2019; 21:15177-15186. [PMID: 31246200 PMCID: PMC6751073 DOI: 10.1039/c9cp02718a] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Time-independent, fully converged, quantum dynamical calculations have been performed for the F + HD (v = 0, j = 0) and F + HD (v = 1, j = 0) reactions on an accurate potential energy surface down to collision energies of 0.01 meV. The two isotopic exit channels, HF + D and DF + H, have been investigated. The calculations reproduce satisfactorily the Feshbach resonance structures for collision energies between 10 and 40 meV, previously reported in the literature for the HF + D channel. Contrary to the results of a former literature work, vibrational excitation of HD is found to enhance reactivity in all cases down to the lowest collision energy investigated. Shape-type orbiting resonances are found for collision energies lower than 2 meV. The resonances appear as peaks in the reaction cross sections that are associated to specific values of the total angular momentum, J. In contrast with the Feshbach resonances at higher energies, the orbiting resonance structure, which is caused by the van der Waals well of the entrance channel, is identical for the HF + D and DF + H exit channels. The orbiting resonance peaks for F + HD (v = 0) are very small, but those for F + HD (v = 1) could be observed, in principle, with a combination of Raman pumping and merged beams methods.
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Affiliation(s)
- V Sáez-Rábanos
- Departamento de Sistemas y Recursos Naturales, E.T.S. de Ingeniería de Montes, Forestal y del Medio Natural, Universidad Politécnica de Madrid, 28040 Madrid, Spain.
| | - J E Verdasco
- Departamento de Química Física, Facultad de Química, Universidad Complutense de Madrid (Unidad Asociada CSIC), 28040 Madrid, Spain.
| | - V J Herrero
- Instituto de Estructura de la Materia (IEM-CSIC), Serrano 123, 28006 Madrid, Spain.
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19
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García-Vela A. A unified theory of weak-field coherent control of the behavior of a resonance state. Phys Chem Chem Phys 2019; 21:7491-7501. [PMID: 30892329 DOI: 10.1039/c9cp01014a] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A unified weak-field control scheme to modify the two properties that determine the whole behavior of a resonance state, namely the lifetime and the asymptotic fragment distribution produced upon resonance decay, is proposed. Control is exerted through quantum interference induced between overlapping resonances of the system, by exciting two different energies at which the resonances overlap. The scheme applies a laser field consisting of a first pulse that excites the energy of the resonance to be controlled, and two additional pulses that excite another different energy to induce interference, with a delay time with respect to the first pulse. Each of the two additional pulses is used to control one of the two resonance properties, by adjusting its corresponding delay time: with a relatively short delay time the second pulse controls the resonance lifetime, while with a very long delay time the third pulse modifies the asymptotic fragment distribution produced. The efficiency of the control of each resonance property is found to be strongly dependent on the choice of the second interfering energy, which allows for a more flexible control optimization by choosing a different energy for each property. The theory underlying the interference mechanism of the control scheme is developed and presented, and is applied to analyze and explain the results obtained. The present scheme thus appears to be a useful tool for controlling resonance-mediated molecular processes.
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Affiliation(s)
- A García-Vela
- Instituto de Física Fundamental, Consejo Superior de Investigaciones Científicas, Serrano 123, 28006 Madrid, Spain.
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20
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The effect of large autoionization decay rates (resonance widths) on cold molecular cross-sections and the reflection phenomenon. Chem Phys 2018. [DOI: 10.1016/j.chemphys.2018.08.047] [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]
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21
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García-Vela A. Weak-Field Coherent Control of Molecular Photofragment State Distributions. PHYSICAL REVIEW LETTERS 2018; 121:153204. [PMID: 30362783 DOI: 10.1103/physrevlett.121.153204] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/09/2018] [Indexed: 06/08/2023]
Abstract
It is known that the long-time energy-resolved photofragment state distribution produced upon photodissociation of a molecule cannot be modified in the weak-field limit for a fixed pump pulse spectral profile. This work, however, demonstrates both computationally and mathematically that the above limitation can be circumvented in practice when the molecule presents overlapping resonances. It is shown that when two or more energies where the resonances overlap are excited by different laser pulses delayed in time, interference is induced between the product fragment states associated with the different energies populated. The occurrence of interference is found to be independent of the delay time between the pulses exciting the different energies. Thus, as demonstrated, this finding makes it possible to modify the fragment distribution at a given energy, as far in time and as many times as desired.
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Affiliation(s)
- A García-Vela
- Instituto de Física Fundamental, Consejo Superior de Investigaciones Científicas, Serrano 123, 28006 Madrid, Spain
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22
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P. van der Poel AP, Bethlem HL. A detailed account of the measurements of cold collisions in a molecular synchrotron. EPJ TECHNIQUES AND INSTRUMENTATION 2018; 5:6. [PMID: 30997320 PMCID: PMC6434929 DOI: 10.1140/epjti/s40485-018-0048-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/06/2018] [Accepted: 06/21/2018] [Indexed: 06/09/2023]
Abstract
We have recently demonstrated a general and sensitive method to study low energy collisions that exploits the unique properties of a molecular synchrotron (Van der Poel et al., Phys Rev Lett 120:033402, 2018). In that work, the total cross section for ND3 + Ar collisions was determined from the rate at which ammonia molecules were lost from the synchrotron due to collisions with argon atoms in supersonic beams. This paper provides further details on the experiment. In particular, we derive the model that was used to extract the relative cross section from the loss rate, and present measurements to characterize the spatial and velocity distributions of the stored ammonia molecules and the supersonic argon beams.
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Affiliation(s)
- Aernout P. P. van der Poel
- LaserLaB, Department of Physics and Astronomy, Vrije Universiteit, De Boelelaan 1081, Amsterdam, The Netherlands
| | - Hendrick L. Bethlem
- LaserLaB, Department of Physics and Astronomy, Vrije Universiteit, De Boelelaan 1081, Amsterdam, The Netherlands
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23
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García-Vela A. Unravelling the mechanisms of interference between overlapping resonances. Phys Chem Chem Phys 2018; 20:3882-3887. [PMID: 29354814 DOI: 10.1039/c7cp07769f] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The enhancement of the resonance lifetime that occurs upon interference of two overlapping resonances excited coherently by two pulses with delayed time has been investigated as a function of the pulse temporal width and the delay time between the pulses. A general law predicting quantitatively the optimal delay time that maximizes the lifetime enhancement of the two resonances has been established in terms of the pulse width and of the lifetimes of both resonances when they are excited isolatedly. The specific form of the law and all the results found can be closely related to the characteristic features of the mechanism of interference between the overlapping resonances, providing a detailed understanding on how the mechanism operates. The proposed law is envisioned as a useful tool to design experimental strategies to control the resonance lifetime.
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Affiliation(s)
- A García-Vela
- Instituto de Fsica Fundamental, Consejo Superior de Investigaciones Cientficas, Serrano 123, 28006 Madrid, Spain.
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24
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Pawlak M, Ben-Asher A, Moiseyev N. Simple Closed-Form Expression for Penning Reaction Rate Coefficients for Cold Molecular Collisions by Non-Hermitian Time-Independent Adiabatic Scattering Theory. J Chem Theory Comput 2018; 14:236-241. [PMID: 29182329 DOI: 10.1021/acs.jctc.7b01017] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
We present a simple expression and its derivation for reaction rate coefficients for cold anisotropic collision experiments based on adiabatic variational theory and time-independent non-Hermitian scattering theory. We demonstrate that only the eigenenergies of the resulting one-dimensional Schrödinger equation for different complex adiabats are required. The expression is applied to calculate the Penning ionization rate coefficients of an excited metastable helium atom with molecular hydrogen in an energy range spanning from hundreds of kelvins down to the millikelvin regime. Except for trivial quantities like the masses of the nuclei and the bond length of the diatomic molecule participating in the collision, one needs as input data only the complex potential energy surface (CPES). In calculations, we used recently obtained ab initio CPES by D. Bhattacharya et al. ( J. Chem. Theory Comput. 2017 , 13 , 1682 - 1690 ) without fitting parameters. The results show good accord with current measurements ( Nat. Phys. 2017 , 13 , 35 - 38 ).
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Affiliation(s)
- Mariusz Pawlak
- Faculty of Chemistry, Nicolaus Copernicus University in Toruń , Gagarina 7, 87-100 Toruń, Poland
| | - Anael Ben-Asher
- Schulich Faculty of Chemistry, Technion-Israel Institute of Technology , Haifa 32000, Israel
| | - Nimrod Moiseyev
- Schulich Faculty of Chemistry, Technion-Israel Institute of Technology , Haifa 32000, Israel.,Faculty of Physics, Technion-Israel Institute of Technology , Haifa 32000, Israel
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25
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Zhelyazkova V, Hogan SD. Probing resonant energy transfer in collisions of ammonia with Rydberg helium atoms by microwave spectroscopy. J Chem Phys 2017; 147:244302. [PMID: 29289135 DOI: 10.1063/1.5011406] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
We present the results of experiments demonstrating the spectroscopic detection of Förster resonance energy transfer from NH3 in the X1A1 ground electronic state to helium atoms in 1sns 3S1 Rydberg levels, where n = 37 and n = 40. For these values of n, the 1sns 3S1 → 1snp 3PJ transitions in helium lie close to resonance with the ground-state inversion transitions in NH3 and can be tuned through resonance using electric fields of less than 10 V/cm. In the experiments, energy transfer was detected by direct state-selective electric field ionization of the 3S1 and 3PJ Rydberg levels and by monitoring the population of the 3DJ levels following pulsed microwave transfer from the 3PJ levels. Detection by microwave spectroscopic methods represents a highly state selective, low-background approach to probing the collisional energy transfer process and the environment in which the atom-molecule interactions occur. The experimentally observed electric-field dependence of the resonant energy transfer process, probed both by direct electric field ionization and by microwave transfer, agrees well with the results of calculations performed using a simple theoretical model of the energy transfer process. For measurements performed in zero electric field with atoms prepared in the 1s40s 3S1 level, the transition from a regime in which a single energy transfer channel can be isolated for detection to one in which multiple collision channels begin to play a role has been identified as the NH3 density was increased.
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Affiliation(s)
- V Zhelyazkova
- Department of Physics and Astronomy, University College London, Gower Street, London WC1E 6BT, United Kingdom
| | - S D Hogan
- Department of Physics and Astronomy, University College London, Gower Street, London WC1E 6BT, United Kingdom
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26
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Abstract
We demonstrate a method to probe cold and ultracold chemistry in a single molecular beam. The approach exploits beam slippage, the velocity difference of different species in the same beam, to establish the relative velocity. Average collision energies of 2.5 mK are achieved but with a spread of 100% or more. However, by implementing a dual-slit chopper that can separately fix the velocities of the two species at the interaction region, we achieve precise control over the relative velocity and narrow its spread. Relative velocities of 7-10 ± 1.1 m/s are achieved with an angular divergence less than 0.25°. In the present study, we observe l-changing collisions occurring between Xe Rydberg atoms and Xe ground state atoms at subKelvin temperatures. We show that in this case the collision energies are tunable between 200 to 450 mK with a root-mean-square deviation of ∼18%. Application of the method to other species and access to much lower energies is straightforward.
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Affiliation(s)
- Chandika Amarasinghe
- Department of Chemistry, University of Missouri , Columbia, Missouri 65211, United States
| | - Arthur G Suits
- Department of Chemistry, University of Missouri , Columbia, Missouri 65211, United States
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27
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Wu X, Gantner T, Koller M, Zeppenfeld M, Chervenkov S, Rempe G. A cryofuge for cold-collision experiments with slow polar molecules. Science 2017; 358:645-648. [DOI: 10.1126/science.aan3029] [Citation(s) in RCA: 46] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2017] [Revised: 08/07/2017] [Accepted: 09/25/2017] [Indexed: 11/02/2022]
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28
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Gordon SDS, Zou J, Tanteri S, Jankunas J, Osterwalder A. Energy Dependent Stereodynamics of the Ne(^{3}P_{2})+Ar Reaction. PHYSICAL REVIEW LETTERS 2017; 119:053001. [PMID: 28949716 DOI: 10.1103/physrevlett.119.053001] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/28/2017] [Indexed: 06/07/2023]
Abstract
The stereodynamics of the Ne(^{3}P_{2})+Ar Penning and associative ionization reactions have been studied using a crossed molecular beam apparatus. The experiment uses a curved magnetic hexapole to polarize the Ne(^{3}P_{2}), which is then oriented with a shaped magnetic field in the region where it intersects with a beam of Ar(^{1}S). The ratios of Penning to associative ionization were recorded over a range of collision energies from 320 to 500 cm^{-1} and the data were used to obtain Ω state dependent reactivities for the two reaction channels. These reactivities were found to compare favorably to those predicted in the theoretical work of Brumer et al.
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Affiliation(s)
- Sean D S Gordon
- Institute for Chemical Sciences and Engineering, Ecole Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland
| | - Junwen Zou
- Institute for Chemical Sciences and Engineering, Ecole Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland
| | - Silvia Tanteri
- Institute for Chemical Sciences and Engineering, Ecole Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland
| | - Justin Jankunas
- Institute for Chemical Sciences and Engineering, Ecole Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland
| | - Andreas Osterwalder
- Institute for Chemical Sciences and Engineering, Ecole Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland
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29
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García-Vela A. The structure of a resonance state. Chem Sci 2017; 8:4804-4810. [PMID: 28959402 PMCID: PMC5602369 DOI: 10.1039/c7sc00452d] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2017] [Accepted: 04/04/2017] [Indexed: 11/21/2022] Open
Abstract
The existence of a structure in a resonance state is systematically investigated. A resonance structure is defined as the energy dependence across the resonance width of the fragment state distributions produced upon resonance decay. Different types of resonances, both isolated and overlapping ones, have been explored for this purpose. It is found that isolated resonances do not present an appreciable energy dependence on the product state distributions. On the contrary, overlapping resonances exhibit a clear structure regarding the fragment distributions, which becomes increasingly more pronounced as the intensity of the overlap between the resonances increases. Such an energy dependence of the product distributions arises from the quantum interference between the amplitudes of the overlapping resonances, as demonstrated formally here by the equations derived from the condition of resonance overlap. The application of the present effect to the control of the fragment state distributions produced in a wide variety of molecular processes governed by resonance states is envisioned.
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Affiliation(s)
- A García-Vela
- Instituto de Física Fundamental , Consejo Superior de Investigaciones Científicas , Serrano 123 , 28006 Madrid , Spain .
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30
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Pawlak M, Shagam Y, Klein A, Narevicius E, Moiseyev N. Adiabatic Variational Theory for Cold Atom–Molecule Collisions: Application to a Metastable Helium Atom Colliding with ortho- and para-Hydrogen Molecules. J Phys Chem A 2017; 121:2194-2198. [PMID: 28221791 DOI: 10.1021/acs.jpca.6b13038] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Mariusz Pawlak
- Faculty
of Chemistry, Nicolaus Copernicus University in Toruń, Gagarina
7, 87-100 Toruń, Poland
| | - Yuval Shagam
- Department
of Chemical Physics, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Ayelet Klein
- Department
of Chemical Physics, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Edvardas Narevicius
- Department
of Chemical Physics, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Nimrod Moiseyev
- Schulich
Faculty of Chemistry and Faculty of Physics, Technion−Israel Institute of Technology, Haifa 32000, Israel
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31
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Onvlee J, Vogels SN, van de Meerakker SYT. Unraveling Cold Molecular Collisions: Stark Decelerators in Crossed-Beam Experiments. Chemphyschem 2016; 17:3583-3595. [PMID: 27471830 DOI: 10.1002/cphc.201600604] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2016] [Indexed: 11/11/2022]
Abstract
In the last two decades, enormous progress has been made in the manipulation of molecular beams. In particular, molecular decelerators have been developed with which advanced control over neutral molecules in a beam can be achieved. By using arrays of inhomogeneous and time-varying electric (or magnetic) fields, bunches of molecules can be produced with a tunable velocity, narrow velocity spreads, and almost perfect quantum-state purity. These monochromatic or "tamed" molecular beams are ideally suited to be used in crossed-molecular-beam scattering experiments. Here, we review the first generation of these "cold and controlled" scattering experiments that have been conducted in the last decade and discuss the prospects for this emerging field of research in the years to come.
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Affiliation(s)
- Jolijn Onvlee
- Radboud University, Institute for Molecules and Materials, Heijendaalseweg 135, 6525 AJ, Nijmegen, the Netherlands
| | - Sjoerd N Vogels
- Radboud University, Institute for Molecules and Materials, Heijendaalseweg 135, 6525 AJ, Nijmegen, the Netherlands
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32
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Allmendinger P, Deiglmayr J, Schullian O, Höveler K, Agner JA, Schmutz H, Merkt F. New Method to Study Ion–Molecule Reactions at Low Temperatures and Application to the Reaction. Chemphyschem 2016; 17:3596-3608. [DOI: 10.1002/cphc.201600828] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2016] [Indexed: 11/06/2022]
Affiliation(s)
- Pitt Allmendinger
- Laboratorium für Physikalische Chemie, Vladimir-Prelog-Weg 2 ETH Zürich CH-8093 Zurich Switzerland
| | - Johannes Deiglmayr
- Laboratorium für Physikalische Chemie, Vladimir-Prelog-Weg 2 ETH Zürich CH-8093 Zurich Switzerland
| | - Otto Schullian
- Laboratorium für Physikalische Chemie, Vladimir-Prelog-Weg 2 ETH Zürich CH-8093 Zurich Switzerland
| | - Katharina Höveler
- Laboratorium für Physikalische Chemie, Vladimir-Prelog-Weg 2 ETH Zürich CH-8093 Zurich Switzerland
| | - Josef A. Agner
- Laboratorium für Physikalische Chemie, Vladimir-Prelog-Weg 2 ETH Zürich CH-8093 Zurich Switzerland
| | - Hansjürg Schmutz
- Laboratorium für Physikalische Chemie, Vladimir-Prelog-Weg 2 ETH Zürich CH-8093 Zurich Switzerland
| | - Frédéric Merkt
- Laboratorium für Physikalische Chemie, Vladimir-Prelog-Weg 2 ETH Zürich CH-8093 Zurich Switzerland
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33
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Balakrishnan N. Perspective: Ultracold molecules and the dawn of cold controlled chemistry. J Chem Phys 2016; 145:150901. [DOI: 10.1063/1.4964096] [Citation(s) in RCA: 157] [Impact Index Per Article: 19.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- N. Balakrishnan
- Department of Chemistry, University of Nevada, Las Vegas, Nevada 89154, USA
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34
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Jachymski K, Hapka M, Jankunas J, Osterwalder A. Experimental and Theoretical Studies of Low‐Energy Penning Ionization of NH
3
, CH
3
F, and CHF
3. Chemphyschem 2016; 17:3776-3782. [DOI: 10.1002/cphc.201600608] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2016] [Revised: 08/02/2016] [Indexed: 11/10/2022]
Affiliation(s)
- Krzysztof Jachymski
- Faculty of Physics University of Warsaw Pasteura 5 02-093 Warsaw Poland
- Institute for Theoretical Physics III and Center for Integrated Quantum Science and Technology University of Stuttgart Pfaffenwaldring 57 70550 Stuttgart Germany
| | - Michał Hapka
- Faculty of Chemistry University of Warsaw Pasteura 1 02-093 Warsaw Poland
| | - Justin Jankunas
- Institute for Chemical Sciences and Engineering Ecole Polytechnique Fédérale de Lausanne (EPFL) 1015 Lausanne Switzerland
- Deceased
| | - Andreas Osterwalder
- Institute for Chemical Sciences and Engineering Ecole Polytechnique Fédérale de Lausanne (EPFL) 1015 Lausanne Switzerland
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35
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Jankunas J, Jachymski K, Hapka M, Osterwalder A. Communication: Importance of rotationally inelastic processes in low-energy Penning ionization of CHF3. J Chem Phys 2016; 144:221102. [DOI: 10.1063/1.4953908] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Justin Jankunas
- Institute for Chemical Sciences and Engineering, Ecole Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland
| | - Krzysztof Jachymski
- Faculty of Physics, University of Warsaw, Pasteura 5, 02-093 Warsaw, Poland
- Institute for Theoretical Physics III and Center for Integrated Quantum Science and Technology, University of Stuttgart, Pfaffenwaldring 57, 70550 Stuttgart, Germany
| | - Michał Hapka
- Faculty of Chemistry, University of Warsaw, Pasteura 1, 02-093 Warsaw, Poland
| | - Andreas Osterwalder
- Institute for Chemical Sciences and Engineering, Ecole Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland
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36
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Sheffield LS, Woo SO, Rathnayaka KDD, Lyuksyutov IF, Herschbach DR. Production of high density molecular beams with wide velocity scanning. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2016; 87:064102. [PMID: 27370474 DOI: 10.1063/1.4953613] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
We describe modifications of a pulsed rotating supersonic beam source that improve performance, particularly increasing the beam density and sharpening the pulse profiles. As well as providing the familiar virtues of a supersonic molecular beam (high intensity, narrowed velocity distribution, and drastic cooling of rotation and vibration), the rotating source enables scanning the translational velocity over a wide range. Thereby, beams of any atom or molecule available as a gas can be slowed or speeded. Using Xe beams in the slowing mode, we have obtained lab speeds down to about 40 ± 5 m/s with density near 10(11) cm(-3) and in the speeding mode lab speeds up to about 660 m/s and density near 10(14) cm(-3). We discuss some congenial applications. Providing low lab speeds can markedly enhance experiments using electric or magnetic fields to deflect, steer, or further slow polar or paramagnetic molecules. The capability to scan molecular speeds facilitates merging velocities with a codirectional partner beam, enabling study of collisions at very low relative kinetic energies, without requiring either beam to be slow.
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Affiliation(s)
- L S Sheffield
- Department of Physics and Astronomy, Texas A&M University, College Station, Texas 77843, USA
| | - S O Woo
- Department of Physics and Astronomy, Texas A&M University, College Station, Texas 77843, USA
| | - K D D Rathnayaka
- Department of Physics and Astronomy, Texas A&M University, College Station, Texas 77843, USA
| | - I F Lyuksyutov
- Department of Physics and Astronomy, Texas A&M University, College Station, Texas 77843, USA
| | - D R Herschbach
- Department of Physics and Astronomy, Texas A&M University, College Station, Texas 77843, USA
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37
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Costes M, Naulin C. Observation of quantum dynamical resonances in near cold inelastic collisions of astrophysical molecules. Chem Sci 2016; 7:2462-2469. [PMID: 28660016 PMCID: PMC5477044 DOI: 10.1039/c5sc04557f] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2015] [Accepted: 01/07/2016] [Indexed: 12/28/2022] Open
Abstract
Quantum resonances in inelastic collisions, predicted by theory and detected at low energies in a crossed-beam experiment, are reviewed.
This mini review summarizes experimental findings of quantum dynamical resonances in inelastic collisions at energies equivalent to temperatures of a few to a few tens of Kelvin, corresponding to physical conditions prevailing in dense molecular clouds of the interstellar medium. Information obtained is thus relevant to collision energy transfer modelling in such media. Crossed-beam scattering experiments performed at Bordeaux university for inelastic collisions of important astrophysical molecules such as CO with H2 or He and O2 with H2 are described. The peaks that show up in the collision energy dependence of the state-to-state integral cross sections for the lowest rotational excitation transitions reveal the quantum nature of such processes. They are ascribed as shape and Feshbach resonances by comparison with the results of close coupling quantum mechanical calculations performed concomitantly on accurate potential energy surfaces.
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Affiliation(s)
- Michel Costes
- Université de Bordeaux , Institut des Sciences Moléculaires , 33405 Talence Cedex , France . .,CNRS , UMR 5255 , 33405 Talence Cedex , France
| | - Christian Naulin
- Université de Bordeaux , Institut des Sciences Moléculaires , 33405 Talence Cedex , France . .,CNRS , UMR 5255 , 33405 Talence Cedex , France
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38
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Onvlee J, Avoird AVD, Groenenboom G, van de Meerakker SYT. Probing Scattering Resonances in (Ultra)Cold Inelastic NO–He Collisions. J Phys Chem A 2016; 120:4770-7. [PMID: 26760050 DOI: 10.1021/acs.jpca.5b11951] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Jolijn Onvlee
- Radboud University, Institute
for Molecules and Materials, Heijendaalseweg 135, 6525 AJ Nijmegen, The Netherlands
| | - Ad van der Avoird
- Radboud University, Institute
for Molecules and Materials, Heijendaalseweg 135, 6525 AJ Nijmegen, The Netherlands
| | - Gerrit Groenenboom
- Radboud University, Institute
for Molecules and Materials, Heijendaalseweg 135, 6525 AJ Nijmegen, The Netherlands
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Eberle P, Dörfler AD, von Planta C, Ravi K, Haas D, Zhang D, van de Meerakker SYT, Willitsch S. Ion-Atom and Ion-Molecule Hybrid Systems: Ion-Neutral Chemistry at Ultralow Energies. ACTA ACUST UNITED AC 2015. [DOI: 10.1088/1742-6596/635/1/012012] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Jankunas J, Reisyan KS, Rakitzis TP, Osterwalder A. Oriented O(3P2), Ne(3P2), and He(3S1) atoms emerging from a bent magnetic guide. Mol Phys 2015. [DOI: 10.1080/00268976.2015.1095363] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Affiliation(s)
- Justin Jankunas
- Institute for Chemical Sciences and Engineering, Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
| | - Kevin S. Reisyan
- Institute for Chemical Sciences and Engineering, Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
| | - T. Peter Rakitzis
- Department of Physics, University of Crete, and Institute of Electronic Structure and Laser, Foundation for Research and Technology-Hellas, Heraklion-Crete, Greece
| | - Andreas Osterwalder
- Institute for Chemical Sciences and Engineering, Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
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Shagam Y, Klein A, Skomorowski W, Yun R, Averbukh V, Koch CP, Narevicius E. Molecular hydrogen interacts more strongly when rotationally excited at low temperatures leading to faster reactions. Nat Chem 2015; 7:921-6. [DOI: 10.1038/nchem.2359] [Citation(s) in RCA: 67] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2015] [Accepted: 08/25/2015] [Indexed: 11/09/2022]
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Pawlak M, Shagam Y, Narevicius E, Moiseyev N. Adiabatic theory for anisotropic cold molecule collisions. J Chem Phys 2015; 143:074114. [PMID: 26298122 DOI: 10.1063/1.4928690] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Mariusz Pawlak
- Schulich Faculty of Chemistry, Technion–Israel Institute of Technology, Haifa 32000, Israel
- Faculty of Chemistry, Nicolaus Copernicus University in Toruń, Gagarina 7, 87-100 Toruń, Poland
| | - Yuval Shagam
- Department of Chemical Physics, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Edvardas Narevicius
- Department of Chemical Physics, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Nimrod Moiseyev
- Schulich Faculty of Chemistry, Technion–Israel Institute of Technology, Haifa 32000, Israel
- Faculty of Physics, Technion–Israel Institute of Technology, Haifa 32000, Israel
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