1
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Plomp V, Wang XD, Kłos J, Dagdigian PJ, Lique F, Onvlee J, van de Meerakker SY. Imaging Resonance Effects in C + H 2 Collisions Using a Zeeman Decelerator. J Phys Chem Lett 2024; 15:4602-4611. [PMID: 38640083 PMCID: PMC11071073 DOI: 10.1021/acs.jpclett.3c03379] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2023] [Revised: 04/05/2024] [Accepted: 04/05/2024] [Indexed: 04/21/2024]
Abstract
An intriguing phenomenon in molecular collisions is the occurrence of scattering resonances, which originate from bound and quasi-bound states supported by the interaction potential at low collision energies. The resonance effects in the scattering behavior are extraordinarily sensitive to the interaction potential, and their observation provides one of the most stringent tests for theoretical models. We present high-resolution measurements of state-resolved angular scattering distributions for inelastic collisions between Zeeman-decelerated C(3P1) atoms and para-H2 molecules at collision energies ranging from 77 cm-1 down to 0.5 cm-1. Rapid variations in the angular distributions were observed, which can be attributed to the consecutive reduction of contributing partial waves and effects of scattering resonances. The measurements showed excellent agreement with distributions predicted by ab initio quantum scattering calculations. However, discrepancies were found at specific collision energies, which most likely originate from an incorrectly predicted quasi-bound state. These observations provide exciting prospects for further high-precision and low-energy investigations of scattering processes that involve paramagnetic species.
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Affiliation(s)
- Vikram Plomp
- Radboud
University, Institute for Molecules and Materials, Heijendaalseweg 135, 6525 AJ Nijmegen, The Netherlands
| | - Xu-Dong Wang
- Radboud
University, Institute for Molecules and Materials, Heijendaalseweg 135, 6525 AJ Nijmegen, The Netherlands
| | - Jacek Kłos
- University
of Maryland, Department of Physics,
Joint Quantum Institute, College
Park, Maryland 20742, United States of America
| | - Paul J. Dagdigian
- Johns
Hopkins University, Department of Chemistry, Baltimore, Maryland 21218, United States
of America
| | - François Lique
- Université
de Rennes, Institut de Physique
de Rennes, 263 avenue
du Général Leclerc, Rennes CEDEX 35042, France
| | - Jolijn Onvlee
- Radboud
University, Institute for Molecules and Materials, Heijendaalseweg 135, 6525 AJ Nijmegen, The Netherlands
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2
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Mukherjee N. Quantum-Controlled Collisions of H 2 Molecules. J Phys Chem A 2023; 127:418-438. [PMID: 36602238 DOI: 10.1021/acs.jpca.2c06808] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
The amount of information that can be obtained from a scattering experiment depends upon the precision with which the quantum states are defined in the incoming channel. By precisely defining the incoming states and measuring the outgoing states in a scattering experiment, we set up the boundary condition for experimentally solving the Schrödinger equation. In this Perspective we discuss cold inelastic scattering experiments using the most theoretically tractable H2 and its isotopologues as the target. We prepare the target in a precisely defined rovibrational (v, j, m) quantum state using a special coherent optical technique called the Stark-induced adiabatic Raman passage (SARP). v and j represent the quantum numbers of the vibrational and rotational energy levels, and m refers to the projection of the rotational angular momentum vector j on a suitable quantization axis in the laboratory frame. Selection of the m quantum numbers defines the alignment of the molecular frame, which is necessary to probe the anisotropic interactions. For us to achieve the collision temperature in the range of a few degrees Kelvin, we co-expand the colliding partners in a mixed supersonic beam that is collimated to define a direction for the collision velocity. When the bond axis is aligned with respect to a well-defined collision velocity, SARP achieves stereodynamic control at the quantum scale. Through various examples of rotationally inelastic cold scattering experiments, we show how SARP coherently controls the dynamics of anisotropic interactions by preparing quantum superpositions of the orientational m states within a single rovibrational (v, j) energy state. A partial wave analysis, which has been developed for the cold scattering experiments, shows dominance of a resonant orbital that leaves its mark in the scattering angular distribution. These highly controlled cold collision experiments at the single partial wave limit allow the most direct comparison with the results of theoretical computations, necessary for accurate modeling of the molecular interaction potential.
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Affiliation(s)
- Nandini Mukherjee
- Department of Chemistry, Stanford University, Stanford, California94305, United States
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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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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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5
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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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6
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Yang D, Xie D, Guo H. Stereodynamical Control of Cold Collisions of Polyatomic Molecules with Atoms. J Phys Chem Lett 2022; 13:1777-1784. [PMID: 35167302 DOI: 10.1021/acs.jpclett.2c00187] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Scattering between atomic and/or molecular species can be controlled by manipulating the orientation or alignment of the collision partners. Such stereodynamics is particularly pronounced at cold (∼1 K) collision temperatures because of the presence of resonances. Comparing to the extensively studied atomic and diatomic species, polyatomic molecules with strong steric anisotropy could provide a more sophisticated platform for studying such stereodynamics. Here, we provide the quantum mechanical framework for understanding state-to-state stereodynamics in rotationally inelastic scattering of polyatomic molecules with atoms and apply it to cold collision of oriented H2O with He on a highly accurate potential energy surface. It is shown that strong stereodynamical control can be achieved near 1 K via shape resonances. Furthermore, quantum interference in scattering of a coherently prepared initial state of the H2O species is explored, which is shown to be significant.
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Affiliation(s)
- Dongzheng Yang
- Department of Chemistry and Chemical Biology, University of New Mexico, Albuquerque, New Mexico 87131, United States
| | - Daiqian Xie
- Institute of Theoretical and Computational Chemistry, Key Laboratory of Mesoscopic Chemistry, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210093, China
| | - Hua Guo
- Department of Chemistry and Chemical Biology, University of New Mexico, Albuquerque, New Mexico 87131, United States
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7
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Zhao B, Pan JW. Quantum control of reactions and collisions at ultralow temperatures. Chem Soc Rev 2022; 51:1685-1701. [PMID: 35169822 DOI: 10.1039/d1cs01040a] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
At temperatures close to absolute zero, the molecular reactions and collisions are dominantly governed by quantum mechanics. Remarkable quantum phenomena such as quantum tunneling, quantum threshold behavior, quantum resonances, quantum interference, and quantum statistics are expected to be the main features in ultracold reactions and collisions. Ultracold molecules offer great opportunities and challenges in the study of these intriguing quantum phenomena in molecular processes. In this article, we review the recent progress in the preparation of ultracold molecules and the study of ultracold reactions and collisions using ultracold molecules. We focus on the controlled ultracold chemistry and the scattering resonances at ultralow temperatures. The challenges in understanding the complex ultracold reactions and collisions are also discussed.
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Affiliation(s)
- Bo Zhao
- Hefei National Laboratory for Physical Sciences at the Microscale and Department of Modern Physics, University of Science and Technology of China, Hefei, Anhui 230026, China. .,Shanghai Branch, CAS Center for Excellence and Synergetic Innovation Center in Quantum Information and Quantum Physics, University of Science and Technology of China, Shanghai 201315, China.,Shanghai Research Center for Quantum Sciences, Shanghai 201315, China
| | - Jian-Wei Pan
- Hefei National Laboratory for Physical Sciences at the Microscale and Department of Modern Physics, University of Science and Technology of China, Hefei, Anhui 230026, China. .,Shanghai Branch, CAS Center for Excellence and Synergetic Innovation Center in Quantum Information and Quantum Physics, University of Science and Technology of China, Shanghai 201315, China.,Shanghai Research Center for Quantum Sciences, Shanghai 201315, China
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8
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Plomp V, Wang XD, Lique F, Kłos J, Onvlee J, van de Meerakker SYT. High-Resolution Imaging of C + He Collisions using Zeeman Deceleration and Vacuum-Ultraviolet Detection. J Phys Chem Lett 2021; 12:12210-12217. [PMID: 34928163 PMCID: PMC8724800 DOI: 10.1021/acs.jpclett.1c03643] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2021] [Accepted: 12/13/2021] [Indexed: 05/25/2023]
Abstract
High-resolution measurements of angular scattering distributions provide a sensitive test for theoretical descriptions of collision processes. Crossed beam experiments employing a decelerator and velocity map imaging have proven successful to probe collision cross sections with extraordinary resolution. However, a prerequisite to exploit these possibilities is the availability of a near-threshold state-selective ionization scheme to detect the collision products, which for many species is either absent or inefficient. We present the first implementation of recoil-free vacuum ultraviolet (VUV) based detection in scattering experiments involving a decelerator and velocity map imaging. This allowed for high-resolution measurements of state-resolved angular scattering distributions for inelastic collisions between Zeeman-decelerated carbon C(3P1) atoms and helium atoms. We fully resolved diffraction oscillations in the angular distributions, which showed excellent agreement with the distributions predicted by quantum scattering calculations. Our approach offers exciting prospects to investigate a large range of scattering processes with unprecedented precision.
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Affiliation(s)
- Vikram Plomp
- Radboud
University, Institute for Molecules and
Materials, Heijendaalseweg
135, 6525 AJ Nijmegen, The Netherlands
| | - Xu-Dong Wang
- Radboud
University, Institute for Molecules and
Materials, Heijendaalseweg
135, 6525 AJ Nijmegen, The Netherlands
| | - François Lique
- Université
de Rennes, Institut de Physique de Rennes, 263 avenue du Général
Leclerc, Rennes 35042 CEDEX, France
| | - Jacek Kłos
- University
of Maryland, Department of Physics, Joint
Quantum Institute, College Park, Maryland 20742, United States of America
| | - Jolijn Onvlee
- Radboud
University, Institute for Molecules and
Materials, Heijendaalseweg
135, 6525 AJ Nijmegen, The Netherlands
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9
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Wang YF, Du TY, Dai DX, Xiao CL, Yang XM. A slow and clean fluorine atom beam source based on ultraviolet laser photolysis. CHINESE J CHEM PHYS 2021. [DOI: 10.1063/1674-0068/cjcp2102033] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Affiliation(s)
- Yu-feng Wang
- State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China
- School of Chemical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Tian-yu Du
- State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China
- School of Chemical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Dong-xu Dai
- State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China
| | - Chun-lei Xiao
- State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China
| | - Xue-ming Yang
- State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China
- College of Science, Southern University of Science and Technology, Shenzhen 518055, China
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10
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Zhou H, Perreault WE, Mukherjee N, Zare RN. Shape resonance determined from angular distribution in D 2 (v = 2, j = 2) + He → D 2 (v = 2, j = 0) + He cold scattering. J Chem Phys 2021; 154:104309. [PMID: 33722006 DOI: 10.1063/5.0045087] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
We find an l = 2 shape resonance fingerprinted in the angular distribution of the cold (∼1 K) Δj = 2 rotationally inelastic collision of D2 with He in a single supersonic expansion. The Stark-induced adiabatic Raman passage is used to prepare D2 in the (v = 2, j = 2) rovibrational level with control of the spatial distribution of the bond axis of the molecule by magnetic sublevel selection. We show that the rate of Δj = 2 D2-D2 relaxation is nearly two orders of magnitude weaker than that of D2-He. This suggests that the strong D2-He scattering is caused by an orbiting resonance that is highly sensitive to the shape of the long-range potential.
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Affiliation(s)
- Haowen Zhou
- Department of Chemistry, Stanford University, Stanford, California 94305, USA
| | - William E Perreault
- Department of Chemistry, Stanford University, Stanford, California 94305, USA
| | - Nandini Mukherjee
- Department of Chemistry, Stanford University, Stanford, California 94305, USA
| | - Richard N Zare
- Department of Chemistry, Stanford University, Stanford, California 94305, USA
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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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Morita M, Balakrishnan N. Stereodynamics of ultracold rotationally inelastic collisions. J Chem Phys 2020; 153:184307. [PMID: 33187407 DOI: 10.1063/5.0030808] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Recent experiments on rotational quenching of HD in the v = 1, j = 2 rovibrational state in collisions with H2, D2, and He near 1 K have revealed strong stereodynamic preference stemming from isolated shape resonances. So far, the experiments and subsequent theoretical analyses have considered the initial HD rotational state in an orientation specified by the projection quantum number m or a coherent superposition of different m states. However, it is known that such stereodynamic control is generally not effective in the ultracold energy regime due to the dominance of the incoming s-wave (l = 0, partial wave). Here, we provide a detailed analysis of the stereodynamics of rotational quenching of HD by He with both m and m' resolution, where m' refers to the inelastically scattered HD. We show the existence of a significant m dependence in the m'-resolved differential and integral cross sections even in the ultracold s-wave regime with a factor greater than 60 for j = 2 → j' = 1 and a factor greater than 1300 for j = 3 → j' = 2 transitions. In the helicity frame, however, the integral cross section has no initial orientation (k) dependence in the ultracold energy regime, even resolving with respect to the final orientation (k'). The distribution of final rotational state orientations (k') is found to be statistical (uniform), regardless of the initial orientation.
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Affiliation(s)
- Masato Morita
- Department of Chemistry and Biochemistry, University of Nevada, Las Vegas, Nevada 89154, USA
| | - Naduvalath Balakrishnan
- Department of Chemistry and Biochemistry, University of Nevada, Las Vegas, Nevada 89154, USA
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13
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Heid CG, Bentham IP, Walpole V, Gheorghe R, Jambrina PG, Aoiz FJ, Brouard M. Probing the location of the unpaired electron in spin-orbit changing collisions of NO with Ar. Phys Chem Chem Phys 2020; 22:22289-22301. [PMID: 33005915 DOI: 10.1039/d0cp04228e] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Understanding the molecular forces that drive a reaction or scattering process lies at the heart of molecular dynamics. Here, we present a combined experimental and theoretical study of the spin-orbit changing scattering dynamics of oriented NO molecules with Ar atoms. Using our crossed molecular beam apparatus, we have recorded velocity-map ion images and extracted differential and integral cross sections of the scattering process in the side-on geometry. We observe an overall preference for collisions close to the N atom in the spin-orbit changing manifold, which is a direct consequence of the location of the unpaired electron on the potential energy surface. In addition, a prominent forward scattered feature is observed for intermediate, even rotational transitions when the atom approaches the molecule from the O-end. The appearance of this peak originates from an attractive well on the A' potential energy surface, which efficiently directs high impact parameter trajectories towards the region of high unpaired electron density near the N-end of the molecule. The ability to orient molecules prior to collision, both experimentally and theoretically, allows us to sample different regions of the potential energy surface(s) and unveil the associated collision pathways.
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Affiliation(s)
- Cornelia G Heid
- Department of Chemistry, University of Oxford, The Chemistry Research Laboratory, 12 Mansfield Road, Oxford, OX1 3TA, UK.
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14
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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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15
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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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16
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Toscano J, Lewandowski HJ, Heazlewood BR. Cold and controlled chemical reaction dynamics. Phys Chem Chem Phys 2020; 22:9180-9194. [DOI: 10.1039/d0cp00931h] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
State-to-state chemical reaction dynamics, with complete control over the reaction parameters, offers unparalleled insight into fundamental reactivity.
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Affiliation(s)
- Jutta Toscano
- JILA and the Department of Physics
- University of Colorado
- Boulder
- USA
| | | | - Brianna R. Heazlewood
- Physical and Theoretical Chemistry Laboratory (PTCL)
- Department of Chemistry
- University of Oxford
- Oxford
- UK
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17
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Jambrina PG, Croft JFE, Guo H, Brouard M, Balakrishnan N, Aoiz FJ. Stereodynamical Control of a Quantum Scattering Resonance in Cold Molecular Collisions. PHYSICAL REVIEW LETTERS 2019; 123:043401. [PMID: 31491255 DOI: 10.1103/physrevlett.123.043401] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/13/2019] [Indexed: 06/10/2023]
Abstract
Cold collisions of light molecules are often dominated by a single partial wave resonance. For the rotational quenching of HD (v=1, j=2) by collisions with ground state para-H_{2}, the process is dominated by a single L=2 partial wave resonance centered around 0.1 K. Here, we show that this resonance can be switched on or off simply by appropriate alignment of the HD rotational angular momentum relative to the initial velocity vector, thereby enabling complete control of the collision outcome.
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Affiliation(s)
- Pablo G Jambrina
- Departamento de Química Física. Universidad de Salamanca, Salamanca 37008, Spain
| | - James F E Croft
- The Dodd-Walls Centre for Photonic and Quantum Technologies, Dunedin 9054, New Zealand and Department of Physics, University of Otago, Dunedin 9054, New Zealand
| | - Hua Guo
- Department of Chemistry and Chemical Biology, University of New Mexico, Albuquerque, New Mexico 87131, USA
| | - Mark Brouard
- The Department of Chemistry, University of Oxford, The Chemistry Research Laboratory, Oxford OX1 3TA, United Kingdom
| | - Naduvalath Balakrishnan
- Department of Chemistry and Biochemistry, University of Nevada, Las Vegas, Nevada 89154, USA
| | - F Javier Aoiz
- Departamento de Química Física. Universidad Complutense. Madrid 28040, Spain
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18
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Perreault WE, Mukherjee N, Zare RN. HD (v = 1, j = 2, m) orientation controls HD-He rotationally inelastic scattering near 1 K. J Chem Phys 2019; 150:174301. [PMID: 31067864 DOI: 10.1063/1.5096531] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
To investigate how molecular orientations affect low energy scattering, we have studied the rotational relaxation of HD (v = 1, j = 2, m) → (v' = 1, j' = 0) by collision with ground-state He, where v, j, and m designate the vibrational, rotational, and magnetic quantum numbers, respectively. We experimentally probed different collision geometries by preparing three specific m sublevels, including an m entangled sublevel, belonging to a single rovibrational (v = 1, j = 2) energy level within the ground electronic state of HD using Stark-induced adiabatic Raman passage. Low collision energies (0-5 K) were achieved by coexpanding a 1:19 HD:He mixture in a highly collimated supersonic beam, which has defined the direction of the collision velocity and restricted the incoming orbital angular momentum states, defined by the quantum number l, to l ≤ 2. Partial wave analysis of experimental data shows that a single l = 2 input orbital dominates the scattered angular distribution, implying the presence of a collisional resonance. The differential scattering angular distribution exhibits a greater than fourfold stereodynamic preference for the m = 0 input state vs m = ±2, when the quantization axis is oriented parallel to the collision velocity.
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Affiliation(s)
- William E Perreault
- Department of Chemistry, Stanford University, Stanford, California 94305, USA
| | - Nandini Mukherjee
- Department of Chemistry, Stanford University, Stanford, California 94305, USA
| | - Richard N Zare
- Department of Chemistry, Stanford University, Stanford, California 94305, USA
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19
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Bergeat A, Morales SB, Naulin C, Kłos J, Lique F. Quantum Behavior of Spin-Orbit Inelastic Scattering of C-Atoms by D 2 at Low Energy. Front Chem 2019; 7:164. [PMID: 30984737 PMCID: PMC6448599 DOI: 10.3389/fchem.2019.00164] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2019] [Accepted: 03/04/2019] [Indexed: 11/25/2022] Open
Abstract
Fine-structure populations and collision–induced energy transfer in atoms are of interest for many fields, from combustion to astrophysics. In particular, neutral carbon atoms are known to play a role in interstellar media, either as probes of physical conditions (ground state 3Pj spin-orbit populations), or as cooling agent (collisional excitation followed by radiative decay). This work aims at investigating the spin-orbit excitation of atomic carbon in its ground electronic state due to collisions with molecular deuterium, an isotopic variant of H2, the most abundant molecule in the interstellar medium. Spin-orbit excitations of C(3Pj) by H2 or D2 are governed by non-adiabatic and spin-orbit couplings, which make the theoretical treatment challenging, since the Born-Oppenheimer approximation no longer holds. Inelastic collisional cross-sections were determined for the C(3P0) + D2 → C(3Pj) + D2 (with j = 1 and 2) excitation process. Experimental data were acquired in a crossed beam experiment at low collision energies, down to the excitation thresholds (at 16.42 and 43.41 cm−1, respectively). C-atoms were produced mainly in their ground spin-orbit state, 3P0, by dissociation of CO in a dielectric discharge through an Even-Lavie pulsed valve. The C-atom beam was crossed with a D2 beam from a second valve. The state-to-state cross-sections were derived from the C(3Pj) (j = 1 or 2) signal measured as a function of the beam crossing angle, i.e., as a function of the collision energy. The results show different quantum behaviors for excitation to C(3P1) or C(3P2) when C(3P0) collides with ortho-D2 or normal-D2. These experimental results are analyzed and discussed in the light of highly accurate quantum calculations. A good agreement between experimental and theoretical results is found. The present data are compared with those obtained for the C-He and C-H2 collisional systems to get new insights into the dynamics of collision induced spin-orbit excitation/relaxation of atomic carbon.
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Affiliation(s)
| | | | | | - Jacek Kłos
- Department of Chemistry and Biochemistry, University of Maryland, College Park, MD, United States
| | - François Lique
- LOMC - UMR 6294, CNRS-Université du Havre, Le Havre, France
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20
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Perreault WE, Mukherjee N, Zare RN. Supersonic beams of mixed gases: A method for studying cold collisions. Chem Phys 2018. [DOI: 10.1016/j.chemphys.2018.02.017] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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21
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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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22
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Understanding the quantum nature of low-energy C( 3P j ) + He inelastic collisions. Nat Chem 2018; 10:519-522. [PMID: 29662206 DOI: 10.1038/s41557-018-0030-y] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2017] [Accepted: 02/16/2018] [Indexed: 11/08/2022]
Abstract
Inelastic collisions that occur between open-shell atoms and other atoms or molecules, and that promote a spin-orbit transition, involve multiple interaction potentials. They are non-adiabatic by nature and cannot be described within the Born-Oppenheimer approximation; in particular, their theoretical modelling becomes very challenging when the collision energies have values comparable to the spin-orbit splitting. Here we study inelastic collisions between carbon in its ground state C(3Pj=0) and helium atoms-at collision energies in the vicinity of spin-orbit excitation thresholds (~0.2 and 0.5 kJ mol-1)-that result in spin-orbit excitation to C(3Pj=1) and C(3Pj=2). State-to-state integral cross-sections are obtained from crossed-beam experiments with a beam source that provides an almost pure beam of C(3Pj=0) . We observe very good agreement between experimental and theoretical results (acquired using newly calculated potential energy curves), which validates our characterization of the quantum dynamical resonances that are observed. Rate coefficients at very low temperatures suitable for chemical modelling of the interstellar medium are also calculated.
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23
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Cold quantum-controlled rotationally inelastic scattering of HD with H 2 and D 2 reveals collisional partner reorientation. Nat Chem 2018; 10:561-567. [PMID: 29662208 DOI: 10.1038/s41557-018-0028-5] [Citation(s) in RCA: 55] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2017] [Accepted: 02/16/2018] [Indexed: 11/08/2022]
Abstract
Molecular interactions are best probed by scattering experiments. Interpretation of these studies has been limited by lack of control over the quantum states of the incoming collision partners. We report here the rotationally inelastic collisions of quantum-state prepared deuterium hydride (HD) with H2 and D2 using a method that provides an improved control over the input states. HD was coexpanded with its partner in a single supersonic beam, which reduced the collision temperature to 0-5 K, and thereby restricted the involved incoming partial waves to s and p. By preparing HD with its bond axis preferentially aligned parallel and perpendicular to the relative velocity of the colliding partners, we observed that the rotational relaxation of HD depends strongly on the initial bond-axis orientation. We developed a partial-wave analysis that conclusively demonstrates that the scattering mechanism involves the exchange of internal angular momentum between the colliding partners. The striking differences between H2/HD and D2/HD scattering suggest the presence of anisotropically sensitive resonances.
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24
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Scattering resonances in bimolecular collisions between NO radicals and H 2 challenge the theoretical gold standard. Nat Chem 2018; 10:435-440. [PMID: 29459690 DOI: 10.1038/s41557-018-0001-3] [Citation(s) in RCA: 47] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2017] [Accepted: 12/08/2017] [Indexed: 11/08/2022]
Abstract
Over the last 25 years, the formalism known as coupled-cluster (CC) theory has emerged as the method of choice for the ab initio calculation of intermolecular interaction potentials. The implementation known as CCSD(T) is often referred to as the gold standard in quantum chemistry. It gives excellent agreement with experimental observations for a variety of energy-transfer processes in molecular collisions, and it is used to calibrate density functional theory. Here, we present measurements of low-energy collisions between NO radicals and H2 molecules with a resolution that challenges the most sophisticated quantum chemistry calculations at the CCSD(T) level. Using hitherto-unexplored anti-seeding techniques to reduce the collision energy in a crossed-beam inelastic-scattering experiment, a resonance structure near 14 cm-1 is clearly resolved in the state-to-state integral cross-section, and a unique resonance fingerprint is observed in the corresponding differential cross-section. This resonance structure discriminates between two NO-H2 potentials calculated at the CCSD(T) level and pushes the required accuracy beyond the gold standard.
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25
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van der Poel APP, Zieger PC, van de Meerakker SYT, Loreau J, van der Avoird A, Bethlem HL. Cold Collisions in a Molecular Synchrotron. PHYSICAL REVIEW LETTERS 2018; 120:033402. [PMID: 29400542 DOI: 10.1103/physrevlett.120.033402] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2017] [Indexed: 06/07/2023]
Abstract
We study collisions between neutral, deuterated ammonia molecules (ND_{3}) stored in a 50 cm diameter synchrotron and argon atoms in copropagating supersonic beams. The advantages of using a synchrotron in collision studies are twofold: (i) By storing ammonia molecules many round-trips, the sensitivity to collisions is greatly enhanced; (ii) the collision partners move in the same direction as the stored molecules, resulting in low collision energies. We tune the collision energy in three different ways: by varying the velocity of the stored ammonia packets, by varying the temperature of the pulsed valve that releases the argon atoms, and by varying the timing between the supersonic argon beam and the stored ammonia packets. These give consistent results. We determine the relative, total, integrated cross section for ND_{3}+Ar collisions in the energy range of 40-140 cm^{-1}, with a resolution of 5-10 cm^{-1} and an uncertainty of 7%-15%. Our measurements are in good agreement with theoretical scattering calculations.
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Affiliation(s)
- Aernout P P van der Poel
- LaserLaB, Department of Physics and Astronomy, Vrije Universiteit, De Boelelaan 1081, 1081 HV Amsterdam, The Netherlands
| | - Peter C Zieger
- LaserLaB, Department of Physics and Astronomy, Vrije Universiteit, De Boelelaan 1081, 1081 HV Amsterdam, The Netherlands
- Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, 14195 Berlin, Germany
| | | | - Jérôme Loreau
- Service de Chimie Quantique et Photophysique, Université Libre de Bruxelles (ULB) CP 160/09, 50 avenue F.D. Roosevelt, 1050 Brussels, Belgium
| | - Ad van der Avoird
- Radboud University, Institute for Molecules and Materials, Heijendaalseweg 135, 6525 AJ Nijmegen, The Netherlands
| | - Hendrick L Bethlem
- LaserLaB, Department of Physics and Astronomy, Vrije Universiteit, De Boelelaan 1081, 1081 HV Amsterdam, The Netherlands
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26
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Wang T, Yang T, Xiao C, Sun Z, Zhang D, Yang X, Weichman ML, Neumark DM. Dynamical resonances in chemical reactions. Chem Soc Rev 2018; 47:6744-6763. [DOI: 10.1039/c8cs00041g] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The transition state is a key concept in the field of chemistry and is important in the study of chemical kinetics and reaction dynamics.
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Affiliation(s)
- Tao Wang
- State Key Laboratory of Molecular Reaction Dynamics
- Dalian Institute of Chemical Physics
- Chinese Academy of Sciences
- Dalian
- China
| | - Tiangang Yang
- State Key Laboratory of Molecular Reaction Dynamics
- Dalian Institute of Chemical Physics
- Chinese Academy of Sciences
- Dalian
- China
| | - Chunlei Xiao
- State Key Laboratory of Molecular Reaction Dynamics
- Dalian Institute of Chemical Physics
- Chinese Academy of Sciences
- Dalian
- China
| | - Zhigang Sun
- State Key Laboratory of Molecular Reaction Dynamics
- Dalian Institute of Chemical Physics
- Chinese Academy of Sciences
- Dalian
- China
| | - Donghui Zhang
- State Key Laboratory of Molecular Reaction Dynamics
- Dalian Institute of Chemical Physics
- Chinese Academy of Sciences
- Dalian
- China
| | - Xueming Yang
- State Key Laboratory of Molecular Reaction Dynamics
- Dalian Institute of Chemical Physics
- Chinese Academy of Sciences
- Dalian
- China
| | | | - Daniel M. Neumark
- Department of Chemistry
- University of California at Berkeley
- Berkeley
- USA
- Chemical Sciences Division
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27
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Perreault WE, Mukherjee N, Zare RN. Quantum control of molecular collisions at 1 kelvin. Science 2017; 358:356-359. [DOI: 10.1126/science.aao3116] [Citation(s) in RCA: 97] [Impact Index Per Article: 13.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2017] [Accepted: 09/08/2017] [Indexed: 11/02/2022]
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28
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Yachmenev A, Küpper J. Communication: General variational approach to nuclear-quadrupole coupling in rovibrational spectra of polyatomic molecules. J Chem Phys 2017; 147:141101. [PMID: 29031262 DOI: 10.1063/1.5002533] [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
A general algorithm for computing the quadrupole-hyperfine effects in the rovibrational spectra of polyatomic molecules is presented for the case of ammonia (NH3). The method extends the general variational approach TROVE [J. Mol. Spectrosc. 245, 126-140 (2007)] by adding the extra term in the Hamiltonian that describes the nuclear quadrupole coupling, with no inherent limitation on the number of quadrupolar nuclei in a molecule. We applied the new approach to compute the nitrogen-nuclear-quadrupole hyperfine structure in the rovibrational spectrum of NH314. These results agree very well with recent experimental spectroscopic data for the pure rotational transitions in the ground vibrational and ν2 states and the rovibrational transitions in the ν1, ν3, 2ν4, and ν1 + ν3 bands. The computed hyperfine-resolved rovibrational spectrum of ammonia will be beneficial for the assignment of experimental rovibrational spectra, further detection of ammonia in interstellar space, and studies of the proton-to-electron mass variation.
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Affiliation(s)
- Andrey Yachmenev
- Center for Free-Electron Laser Science, Deutsches Elektronen-Synchrotron DESY, Notkestrasse 85, 22607 Hamburg, Germany
| | - Jochen Küpper
- Center for Free-Electron Laser Science, Deutsches Elektronen-Synchrotron DESY, Notkestrasse 85, 22607 Hamburg, Germany
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29
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Ren Z, Sun Z, Zhang D, Yang X. A review of dynamical resonances in A + BC chemical reactions. REPORTS ON PROGRESS IN PHYSICS. PHYSICAL SOCIETY (GREAT BRITAIN) 2017; 80:026401. [PMID: 28008875 DOI: 10.1088/1361-6633/80/2/026401] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
The concept of the transition state has played an important role in the field of chemical kinetics and reaction dynamics. Reactive resonances in the transition-state region can dramatically enhance the reaction probability; thus investigation of the reactive resonances has attracted great attention from chemical physicists for many decades. In this review, we mainly focus on the recent progress made in probing the elusive resonance phenomenon in the simple A + BC reaction and understanding its nature, especially in the benchmark F/Cl + H2 and their isotopic variants. The signatures of reactive resonances in the integral cross section, differential cross section (DCS), forward- and backward-scattered DCS, and anion photodetachment spectroscopy are comprehensively presented in individual prototype reactions. The dynamical origins of reactive resonances are also discussed in this review, based on information on the wave function in the transition-state region obtained by time-dependent quantum wave-packet calculations.
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Affiliation(s)
- Zefeng Ren
- State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian 116023, Liaoning, People's Republic of China. International Center for Quantum Materials (ICQM) and School of Physics, Peking University, Beijing 100871, People's Republic of China. Collaborative Innovation Center of Quantum Matter, Beijing 100871, People's Republic of China
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30
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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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31
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Yang B, Balakrishnan N, Zhang P, Wang X, Bowman JM, Forrey RC, Stancil PC. Full-dimensional quantum dynamics of CO in collision with H2. J Chem Phys 2016; 145:034308. [DOI: 10.1063/1.4958951] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Benhui Yang
- Department of Physics and Astronomy and the Center for Simulational Physics, The University of Georgia, Athens, Georgia 30602, USA
| | - N. Balakrishnan
- Department of Chemistry, University of Nevada, Las Vegas, Nevada 89154, USA
| | - P. Zhang
- Department of Chemistry, Duke University, Durham, North Carolina 27708, USA
| | - X. Wang
- Department of Chemistry, Emory University, Atlanta, Georgia 30322, USA
| | - J. M. Bowman
- Department of Chemistry, Emory University, Atlanta, Georgia 30322, USA
| | - R. C. Forrey
- Department of Physics, Penn State University, Berks Campus, Reading, Pennsylvania 19610, USA
| | - P. C. Stancil
- Department of Physics and Astronomy and the Center for Simulational Physics, The University of Georgia, Athens, Georgia 30602, USA
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32
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On the importance of full-dimensionality in low-energy molecular scattering calculations. Sci Rep 2016; 6:28449. [PMID: 27333870 PMCID: PMC4917847 DOI: 10.1038/srep28449] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2016] [Accepted: 06/02/2016] [Indexed: 11/29/2022] Open
Abstract
Scattering of H2 on CO is of great importance in astrophysics and also is a benchmark system for comparing theory to experiment. We present here a new 6-dimensional potential energy surface for the ground electronic state of H2-CO with an estimated uncertainty of about 0.6 cm−1 in the global minimum region, several times smaller than achieved earlier. This potential has been used in nearly exact 6-dimensional quantum scattering calculations to compute state-to-state cross-sections measured in low-energy crossed-beam experiments. Excellent agreement between theory and experiment has been achieved in all cases. We also show that the fully 6-dimensional approach is not needed with the current accuracy of experimental data since an equally good agreement with experiment was obtained using only a 4-dimensional treatment, which validates the rigid-rotor approach widely used in scattering calculations. This finding, which disagrees with some literature statements, is important since for larger systems full-dimensional scattering calculations are currently not possible.
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33
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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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34
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Lara M, Chefdeville S, Larregaray P, Bonnet L, Launay JM, Costes M, Naulin C, Bergeat A. S(1D) + ortho-D2 Reaction Dynamics at Low Collision Energies: Complementary Crossed Molecular Beam Experiments and Theoretical Investigations. J Phys Chem A 2016; 120:5274-81. [DOI: 10.1021/acs.jpca.6b01182] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Manuel Lara
- Departamento
de Química Física Aplicada, Facultad de Ciencias, Universidad Autónoma de Madrid, 28049 Madrid, Spain
| | - Simon Chefdeville
- Univ. Bordeaux,
ISM, UMR 5255, F-33400 Talence, France
- CNRS, ISM, UMR 5255, F-33400 Talence, France
| | - Pascal Larregaray
- Univ. Bordeaux,
ISM, UMR 5255, F-33400 Talence, France
- CNRS, ISM, UMR 5255, F-33400 Talence, France
| | - Laurent Bonnet
- Univ. Bordeaux,
ISM, UMR 5255, F-33400 Talence, France
- CNRS, ISM, UMR 5255, F-33400 Talence, France
| | - Jean-Michel Launay
- Institut
de Physique
de Rennes, UMR CNRS 6251, Université de Rennes I, F-35042 Rennes, France
| | - Michel Costes
- Univ. Bordeaux,
ISM, UMR 5255, F-33400 Talence, France
- CNRS, ISM, UMR 5255, F-33400 Talence, France
| | - Christian Naulin
- Univ. Bordeaux,
ISM, UMR 5255, F-33400 Talence, France
- CNRS, ISM, UMR 5255, F-33400 Talence, France
| | - Astrid Bergeat
- Univ. Bordeaux,
ISM, UMR 5255, F-33400 Talence, France
- CNRS, ISM, UMR 5255, F-33400 Talence, France
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35
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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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36
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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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37
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Bergeat A, Onvlee J, Naulin C, van der Avoird A, Costes M. Quantum dynamical resonances in low-energy CO(j = 0) + He inelastic collisions. Nat Chem 2015; 7:349-53. [PMID: 25803474 DOI: 10.1038/nchem.2204] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2014] [Accepted: 02/12/2015] [Indexed: 11/09/2022]
Abstract
In molecular collisions, long-lived complexes may be formed that correspond to quasi-bound states in the van der Waals potential and give rise to peaks in the collision energy-dependent cross-sections. They are known as 'resonances' and their experimental detection remains difficult because their signatures are extremely challenging to resolve. Here, we show a complete characterization of quantum-dynamical resonances occurring in CO-He inelastic collisions with rotational CO(j = 0->1) excitation. Crossed-beam scattering experiments were performed at collision energies as low as 4 cm(-1), equivalent to a temperature of 4 K. Resonance structures in the measured cross-sections were identified by comparison with quantum-mechanical calculations. The excellent agreement found confirms that the potential energy surfaces describing the CO-He van der Waals interaction are perfectly suitable for calculating state-to-state (de)excitation rate coefficients at the very low temperatures needed in chemical modelling of the interstellar medium. We also computed these rate coefficients.
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Affiliation(s)
- Astrid Bergeat
- 1] Université de Bordeaux, Institut des Sciences Moléculaires, Talence Cedex 33405, France [2] CNRS, UMR 5255, Talence Cedex 33405, France
| | - Jolijn Onvlee
- Radboud University Nijmegen, Institute for Molecules and Materials, Heijendaalseweg 135, Nijmegen 6525 AJ, The Netherlands
| | - Christian Naulin
- 1] Université de Bordeaux, Institut des Sciences Moléculaires, Talence Cedex 33405, France [2] CNRS, UMR 5255, Talence Cedex 33405, France
| | - Ad van der Avoird
- Radboud University Nijmegen, Institute for Molecules and Materials, Heijendaalseweg 135, Nijmegen 6525 AJ, The Netherlands
| | - Michel Costes
- 1] Université de Bordeaux, Institut des Sciences Moléculaires, Talence Cedex 33405, France [2] CNRS, UMR 5255, Talence Cedex 33405, France
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Vilà A, González M, Mayol R. Quantum interferences in the photodissociation of Cl2(B) in superfluid helium nanodroplets (4He)N. Phys Chem Chem Phys 2015; 17:32241-50. [DOI: 10.1039/c5cp03575a] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The origin of quantum interferences theoretically found in the photodissociation of chlorine in superfluid 4He nanodroplets was investigated in detail.
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Affiliation(s)
- Arnau Vilà
- Departament de Química Física i IQTC
- Universitat de Barcelona
- 08028 Barcelona
- Spain
| | - Miguel González
- Departament de Química Física i IQTC
- Universitat de Barcelona
- 08028 Barcelona
- Spain
| | - Ricardo Mayol
- Departament d’Estructura i Constituents de la Matèria
- Universitat de Barcelona
- 08028 Barcelona
- Spain
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