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Perera CA, Amarasinghe C, Guo H, Suits AG. Cold collisions of hot molecules. Phys Chem Chem Phys 2023; 25:22595-22606. [PMID: 37602475 DOI: 10.1039/d3cp02071a] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/22/2023]
Abstract
In this Perspective, we review our recent work on rotationally inelastic collisions of highly vibrationally excited NO molecules prepared in single rotational and parity levels at v = 10 using stimulated emission pumping (SEP). This state preparation is employed in a recently developed crossed molecular beam apparatus where two nearly copropagating molecular beams achieve an intersection angle of 4° at the interaction region. This near-copropagating beam geometry of the molecular beams permits very wide tuning of the collision energy, from far above room temperature down to 2 K where we test the theoretical treatment of the attractive part of the potentials and the difference potential for the first time. We have obtained differential cross sections for state-to-state collisions of NO (v = 10) with Ar and Ne in both spin-orbit manifolds using velocity map imaging. Overall good agreement of the experimental results was seen with quantum mechanical close-coupling calculations done on both coupled-cluster and multi-reference configuration interaction potential energy surfaces. Probing cold collisions of NO carrying ∼2 eV of vibrational excitation allows us to test state-of-the-art theory in this extreme nonequilibrium regime.
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Affiliation(s)
- Chatura A Perera
- Department of Chemistry, University of Missouri, Columbia, MO 65211, USA.
| | | | - Hua Guo
- Department of Chemistry and Chemical Biology, University of New Mexico, Albuquerque, New Mexico 87131, USA
| | - Arthur G Suits
- Department of Chemistry, University of Missouri, Columbia, MO 65211, USA.
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2
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Perera CA, Zuo J, Guo H, Suits AG. Differential Cross Sections for Cold, State-to-State Spin-Orbit Changing Collisions of NO( v = 10) with Neon. J Phys Chem A 2022; 126:3338-3346. [PMID: 35605132 DOI: 10.1021/acs.jpca.2c02698] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Inelastic scattering processes have proven a powerful means of investigating molecular interactions, and much current effort is focused on the cold and ultracold regime where quantum phenomena are clearly manifested. Studies of collisions of the open shell nitric oxide (NO) molecule have been central in this effort since the pioneering work of Houston and co-workers in the early 1990s. State-to-state scattering of vibrationally excited molecules in the cold regime introduces challenges that test the suitability of current theoretical methods for ab initio determination of intermolecular potentials, and concomitant electronically nonadiabatic processes raise the bar further. Here we report measurements of differential cross sections for state-to-state spin-orbit changing collisions of NO (v = 10, Ω″ = 1.5, and j″ = 1.5) with neon from 2.3 to 3.5 cm-1 collision energy using our recently developed near-copropagating beam technique. The experimental results are compared with those obtained from quantum scattering calculations on a high-level set of coupled cluster potential energy surfaces and are shown to be in good agreement. The theoretical results suggest that distinct backscattering in the 2.3 cm-1 case arises from overlapping resonances.
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Affiliation(s)
- Chatura A Perera
- Department of Chemistry, University of Missouri, Columbia, Missouri 65211, United States
| | - Junxiang Zuo
- Department of Chemistry and Chemical Biology, University of New Mexico, Albuquerque, New Mexico 87131, United States
| | - Hua Guo
- Department of Chemistry and Chemical Biology, University of New Mexico, Albuquerque, New Mexico 87131, United States
| | - Arthur G Suits
- Department of Chemistry, University of Missouri, Columbia, Missouri 65211, United States
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3
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Pawlak M, Żuchowski PS, Jankowski P. Kinetic Isotope Effect in Low-Energy Collisions between Hydrogen Isotopologues and Metastable Helium Atoms: Theoretical Calculations Including the Vibrational Excitation of the Molecule. J Chem Theory Comput 2021; 17:1008-1016. [PMID: 33475358 PMCID: PMC7877727 DOI: 10.1021/acs.jctc.0c01122] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We present very accurate theoretical results of Penning ionization rate coefficients of the excited metastable helium atoms (4He(23S) and 3He(23S)) colliding with the hydrogen isotopologues (H2, HD, D2) in the ground and first excited rotational and vibrational states at subkelvin regime. The calculations are performed using the current best ab initio interaction energy surface, which takes into account the nonrigidity effects of the molecule. The results confirm a recently observed substantial quantum kinetic isotope effect (Nat. Chem. 2014, 6, 332-335) and reveal that the change of the rotational or vibrational state of the molecule can strongly enhance or suppress the reaction. Moreover, we demonstrate the mechanism of the appearance and disappearance of resonances in Penning ionization. The additional model computations, with the morphed interaction energy surface and mass, give better insight into the behavior of the resonances and thereby the reaction dynamics under study. Our theoretical findings are compared with all available measurements, and comprehensive data for prospective experiments are provided.
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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, Grudzia̧dzka 5, 87-100 Toruń, Poland
| | - Piotr Jankowski
- Faculty of Chemistry, Nicolaus Copernicus University in Toruń, Gagarina 7, 87-100 Toruń, Poland
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4
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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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5
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Zou J, Osterwalder A. Investigation of the low-energy stereodynamics in the Ne( 3P 2) + N 2, CO reactions. J Chem Phys 2020; 153:104306. [PMID: 32933296 DOI: 10.1063/5.0022053] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
We report on an experimental investigation of the low-energy stereodynamics of the energy transfer reactions Ne(3P2) + X, producing Ne(1S) + X+ and [Ne-X]+ (X = N2 or CO). Collision energies in the range 0.2 K-700 K are obtained by using the merged beam technique. Two kinds of product ions are generated by Penning and associative ionization, respectively. The intermediate product [Ne-X]+ in vibrationally excited states can predissociate into bare ions (X+). The experimental ratio of the NeX+ and X+ product ion yields is similar for both molecules at high collision energies but diverge at collision energies below 100 K. This difference is explained by the first excited electronic state of the product ions, which is accessible in the case of CO but lies too high in energy in the case of N2.
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Affiliation(s)
- Junwen Zou
- 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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6
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Amarasinghe C, Perera CA, Suits AG. A versatile molecular beam apparatus for cold/ultracold collisions. J Chem Phys 2020; 152:184201. [PMID: 32414267 DOI: 10.1063/5.0007382] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
We have developed an apparatus capable of performing intrabeam and near-copropagating beam scattering experiments at collision energies from room temperature to below 1 K where interesting quantum phenomena can be observed. A detailed description of the major components of the apparatus, single and dual molecular beam valves, high speed chopper, and the discharge source, is presented. With the intrabeam scattering setup, a novel dual-slit chopper permits collision energies down to millikelvins with a collision energy spread of 20%. With the near-copropagating beam configuration, state-to-state differential cross sections for rotationally inelastic collisions of highly vibrationally excited NO molecules with Ar have been measured at broadly tunable energies documenting the versatility of the instrument. Future applications in stereodynamics and cold state-to-state collisions of vibrationally excited polyatomic molecules are briefly discussed.
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Affiliation(s)
| | - Chatura A Perera
- Department of Chemistry, University of Missouri, Columbia, Missouri 65211, USA
| | - Arthur G Suits
- Department of Chemistry, University of Missouri, Columbia, Missouri 65211, USA
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7
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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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8
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Zou J, Gordon SDS, Osterwalder A. Sub-Kelvin Stereodynamics of the Ne(^{3}P_{2})+N_{2} Reaction. PHYSICAL REVIEW LETTERS 2019; 123:133401. [PMID: 31697548 DOI: 10.1103/physrevlett.123.133401] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/18/2019] [Indexed: 06/10/2023]
Abstract
We present an experimental study of the low-energy stereodynamics of the Ne(^{3}P_{2})+N_{2} reaction. Supersonic expansions of the two reactants are superposed in a merged beam experiment, where individual velocity control of the two beams allows us to reach average relative velocities of zero, yielding minimum collision energies around 60 mK. We combine the merged beam technique with the orientation of the metastable neon atoms and measure the branching between two reaction channels, Penning ionization and associative ionization, as a function of neon orientation and collision energy, covering the range 0.06-700 K. We find that we lose the ability to orient Ne below ≈100 K due to dynamic reorientation. Associative ionization products Ne-N_{2}^{+} predissociate with a probability of 30%-60% and that associative ionization is entirely due to reactions of the Ω=2 state, where the singly occupied p orbital of the Ne^{*} is oriented along the interatomic axis.
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Affiliation(s)
- Junwen Zou
- Institute for Chemical Sciences and Engineering, Ecole Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland
| | - Sean D S Gordon
- 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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9
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Amarasinghe C, Li H, Perera CA, Besemer M, van der Avoird A, Groenenboom GC, Xie C, Guo H, Suits AG. Differential Cross Sections for State-to-State Collisions of NO( v = 10) in Near-Copropagating Beams. J Phys Chem Lett 2019; 10:2422-2427. [PMID: 31021645 DOI: 10.1021/acs.jpclett.9b00847] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
State-to-state differential cross sections for rotationally inelastic collisions of vibrationally excited NO with Ar have been measured in a near-copropagating crossed beam experiment at collision energies of 530 and 30 cm-1. Stimulated emission pumping (SEP) to prepare NO in specific rovibrational levels is coupled with direct-current slice velocity map imaging to obtain a direct measurement of the differential cross sections. The use of nearly copropagating beams to achieve low NO-Ar collision energies and broad collision energy tuning capability are also demonstrated. The experimental differential cross sections (DCSs) for NO in v = 10 in specific rotational and parity states are compared with the corresponding DCSs predicted for NO in v = 0 obtained from quantum mechanical close coupling calculations to highlight the differences between the NO( v = 10)-Ar and NO( v = 0)-Ar interaction potentials.
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Affiliation(s)
- Chandika Amarasinghe
- Department of Chemistry , University of Missouri , Columbia , Missouri 65211 , United States
| | - Hongwei Li
- Department of Chemistry , University of Missouri , Columbia , Missouri 65211 , United States
| | - Chatura A Perera
- Department of Chemistry , University of Missouri , Columbia , Missouri 65211 , United States
| | - Matthieu Besemer
- Radboud University , Institute for Molecules and Materials , Heyendaalseweg 135 , 6525 AJ Nijmegen , The Netherlands
| | - Ad van der Avoird
- Radboud University , Institute for Molecules and Materials , Heyendaalseweg 135 , 6525 AJ Nijmegen , The Netherlands
| | - Gerrit C Groenenboom
- Radboud University , Institute for Molecules and Materials , Heyendaalseweg 135 , 6525 AJ Nijmegen , The Netherlands
| | - Chengjian Xie
- Department of Chemistry and Chemical Biology , University of New Mexico , Albuquerque , New Mexico 87131 , United States
| | - Hua Guo
- Department of Chemistry and Chemical Biology , University of New Mexico , Albuquerque , New Mexico 87131 , United States
| | - Arthur G Suits
- Department of Chemistry , University of Missouri , Columbia , Missouri 65211 , United States
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10
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Bibelnik N, Gersten S, Henson AB, Lavert-Ofir E, Shagam Y, Skomorowski W, Koch CP, Narevicius E. Cold temperatures invert product ratios in Penning ionisation reactions with argon. Mol Phys 2019. [DOI: 10.1080/00268976.2019.1594421] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Affiliation(s)
- Natan Bibelnik
- Department of Chemical and Biological Physics, Weizmann Institute of Science, Rehovot, Israel
| | - Sasha Gersten
- Department of Chemical and Biological Physics, Weizmann Institute of Science, Rehovot, Israel
| | - Alon B Henson
- Department of Chemical and Biological Physics, Weizmann Institute of Science, Rehovot, Israel
| | - Etay Lavert-Ofir
- Department of Chemical and Biological Physics, Weizmann Institute of Science, Rehovot, Israel
| | - Yuval Shagam
- 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
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11
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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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12
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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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13
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Zou J, Gordon SDS, Tanteri S, Osterwalder A. Stereodynamics of Ne( 3P 2) reacting with Ar, Kr, Xe, and N 2. J Chem Phys 2018; 148:164310. [PMID: 29716200 DOI: 10.1063/1.5026952] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
Stereodynamics experiments of Ne(3P2) reacting with Ar, Kr, Xe, and N2 leading to Penning and associative ionization have been performed in a crossed molecular beam apparatus. A curved magnetic hexapole was used to state-select and polarize Ne(3P2) atoms which were then oriented in a rotatable magnetic field and crossed with a beam of Ar, Kr, Xe, or N2. The ratio of associative to Penning ionization was recorded as a function of the magnetic field direction for collision energies between 320 cm-1 and 500 cm-1. Reactivities are obtained for individual states that differ only in Ω, the projection of the neon total angular momentum vector on the inter-particle axis. The results are rationalized on the basis of a model involving a long-range and a short-range reaction mechanism. Substantially lower probability for associative ionization was observed for N2, suggesting that predissociation plays a critical role in the overall reaction pathway.
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Affiliation(s)
- Junwen Zou
- Institute for Chemical Sciences and Engineering, Ecole Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland
| | - Sean D S Gordon
- 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
| | - Andreas Osterwalder
- Institute for Chemical Sciences and Engineering, Ecole Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland
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14
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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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15
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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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16
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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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17
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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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18
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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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19
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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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20
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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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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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22
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Chang YP, Horke DA, Trippel S, Küpper J. Spatially-controlled complex molecules and their applications. INT REV PHYS CHEM 2015. [DOI: 10.1080/0144235x.2015.1077838] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Affiliation(s)
- Yuan-Pin Chang
- Center for Free-Electron Laser Science, DESY, Notkestrasse 85, 22607 Hamburg, Germany
| | - Daniel A. Horke
- Center for Free-Electron Laser Science, DESY, Notkestrasse 85, 22607 Hamburg, Germany
| | - Sebastian Trippel
- Center for Free-Electron Laser Science, DESY, Notkestrasse 85, 22607 Hamburg, Germany
| | - Jochen Küpper
- Center for Free-Electron Laser Science, DESY, Notkestrasse 85, 22607 Hamburg, Germany
- Department of Physics, Universität Hamburg, Luruper Chaussee 149, 22761 Hamburg, Germany
- The Hamburg Center for Ultrafast Imaging, Universität Hamburg, Luruper Chaussee 149, 22761 Hamburg, Germany
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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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Jankunas J, Jachymski K, Hapka M, Osterwalder A. Observation of orbiting resonances in He(3S1) + NH3Penning ionization. J Chem Phys 2015; 142:164305. [DOI: 10.1063/1.4919369] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Affiliation(s)
- Justin Jankunas
- Institute for Chemical Sciences and Engineering, Ecole Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland
| | | | - 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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Abstract
The field of cold molecules has become an important source of new insight in fundamental chemistry and molecular physics. High-resolution spectroscopy benefits from translationally and internally cold molecules by increased interaction times and reduced spectral congestion. Completely new effects in scattering dynamics become accessible with cold and controlled molecules. Many of these experiments use molecular beams as a starting point for the generation of molecular samples. This review gives an overview of methods to produce beams of cold molecules, starting from supersonic expansions or effusive sources, and provides examples of applications in spectroscopy and molecular dynamics studies.
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Affiliation(s)
- Justin Jankunas
- Institute for Chemistry and Chemical Engineering, Ecole Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland
| | - Andreas Osterwalder
- Institute for Chemistry and Chemical Engineering, Ecole Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland
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Jankunas J, Reisyan KS, Osterwalder A. Preparation of state purified beams of He, Ne, C, N, and O atoms. J Chem Phys 2015; 142:104311. [PMID: 25770544 DOI: 10.1063/1.4914332] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
The production and guiding of ground state and metastable C, N, and O atoms in a two-meter-long, bent magnetic guide are described. Pure beams of metastable He((3)S1) and Ne((3)P2), and of ground state N((4)S3/2) and O((3)P2) are obtained using an Even-Lavie valve paired with a dielectric barrier discharge or electron bombardment source. Under these conditions no electronically excited C, N, or O atoms are observed at the exit of the guide. A general valve with electron impact excitation creates, in addition to ground state atoms, electronically excited C((3)P2; (1)D2) and N((2)D5/2; (2)P3/2) species. The two experimental conditions are complimentary, demonstrating the usefulness of a magnetic guide in crossed or merged beam experiments such as those described in Henson et al. [Science 338, 234 (2012)] and Jankunas et al. [J. Chem. Phys. 140, 244302 (2014)].
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Affiliation(s)
- Justin Jankunas
- Institute for Chemical Sciences and Engineering, Ecole Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland
| | - Kevin S Reisyan
- Institute for Chemical Sciences and Engineering, Ecole Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland
| | - Andreas Osterwalder
- Institute for Chemical Sciences and Engineering, Ecole Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland
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Abstract
Coulomb crystals-as a source of translationally cold, highly localized ions-are being increasingly utilized in the investigation of ion-molecule reaction dynamics in the cold regime. To develop a fundamental understanding of ion-molecule reactions, and to challenge existing models that describe the rates, product branching ratios, and temperature dependence of such processes, investigators need to exercise full control over the experimental reaction parameters. This requires not only state selection of the reactants, but also control over the collision process (e.g., the collisional energy and angular momentum) and state-selective product detection. The combination of Coulomb crystals in ion traps with cold neutral-molecule sources is enabling the measurement of state-selective reaction rates in a diverse range of systems. With the development of appropriate product detection techniques, we are moving toward the ultimate goal of examining low-energy, state-to-state ion-molecule reaction dynamics.
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Twyman KS, Bell MT, Heazlewood BR, Softley TP. Production of cold beams of ND3 with variable rotational state distributions by electrostatic extraction of He and Ne buffer-gas-cooled beams. J Chem Phys 2014; 141:024308. [DOI: 10.1063/1.4885855] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Affiliation(s)
- Kathryn S. Twyman
- Department of Chemistry, University of Oxford, Chemistry Research Laboratory, 12 Mansfield Road, Oxford OX1 3TA, United Kingdom
| | - Martin T. Bell
- Department of Chemistry, University of Oxford, Chemistry Research Laboratory, 12 Mansfield Road, Oxford OX1 3TA, United Kingdom
| | - Brianna R. Heazlewood
- Department of Chemistry, University of Oxford, Chemistry Research Laboratory, 12 Mansfield Road, Oxford OX1 3TA, United Kingdom
| | - Timothy P. Softley
- Department of Chemistry, University of Oxford, Chemistry Research Laboratory, 12 Mansfield Road, Oxford OX1 3TA, United Kingdom
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29
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Jankunas J, Bertsche B, Jachymski K, Hapka M, Osterwalder A. Dynamics of gas phase Ne* + NH3 and Ne* + ND3 Penning ionisation at low temperatures. J Chem Phys 2014; 140:244302. [PMID: 24985633 DOI: 10.1063/1.4883517] [Citation(s) in RCA: 75] [Impact Index Per Article: 7.5] [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
| | - Benjamin Bertsche
- Institute for Chemical Sciences and Engineering, Ecole Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland
| | | | - 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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