1
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Mao Y, Chen H, Yang Z, Buren B, Chen M. Stereodynamic control of nonadiabatic processes in low-energy Be +( 2P) + H 2 ( v = 0, j = 2) collisions. Phys Chem Chem Phys 2024; 26:19812-19821. [PMID: 38988212 DOI: 10.1039/d4cp01996b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/12/2024]
Abstract
Controlling the relative arrangement of colliding molecules is crucial for determining the dynamical outcomes of chemical processes and has emerged as a hot spot of experimental research. Here, the quantum scattering calculations are conducted to investigate the stereodynamic control in collisions between Be+(2P) and H2 (v = 0, j = 2), which undergo nonadiabatic transitions to the electronic ground state. Stereodynamic preparation is achieved by controlling the initial alignment of the H2 bond axis relative to the scattering frame. For product BeH+ in the reactive process, the differential cross sections (DCSs) are significantly enhanced in the forward and sideways hemispheres when the alignment angle β is 60°. For the product H2 in the quenching channel, the β = 0° preparation can result in a more than one-fold increase in the DCS at a polar scattering angle of 0°. Furthermore, varying the alignment angle β also has noteworthy effects on the rotational-state distributions of BeH+ products. Specifically, β = 0° preparation can induce the disappearance of the bimodal distribution of rotational states at a collision energy of 0.05 eV.
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Affiliation(s)
- Ye Mao
- Key Laboratory of Materials Modification by Laser, Electron, and Ion Beams (Ministry of Education), School of Physics, Dalian University of Technology, Dalian, 116024, P. R. China.
| | - Hanghang Chen
- Key Laboratory of Materials Modification by Laser, Electron, and Ion Beams (Ministry of Education), School of Physics, Dalian University of Technology, Dalian, 116024, P. R. China.
| | - Zijiang Yang
- Key Laboratory of Materials Modification by Laser, Electron, and Ion Beams (Ministry of Education), School of Physics, Dalian University of Technology, Dalian, 116024, P. R. China.
| | - Bayaer Buren
- School of Science, Shenyang University of Technology, Shenyang 110870, P. R. China.
| | - Maodu Chen
- Key Laboratory of Materials Modification by Laser, Electron, and Ion Beams (Ministry of Education), School of Physics, Dalian University of Technology, Dalian, 116024, P. R. China.
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2
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Mandal B, Croft JFE, Jambrina PG, Guo H, Aoiz FJ, Balakrishnan N. Stereodynamical control of cold HD + D 2 collisions. Phys Chem Chem Phys 2024; 26:18368-18381. [PMID: 38912616 DOI: 10.1039/d4cp01737d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/25/2024]
Abstract
We report full-dimensional quantum calculations of stereodynamic control of HD(v = 1, j = 2) + D2 collisions that has been probed experimentally by Perreault et al. using the Stark-induced adiabatic Raman passage (SARP) technique. Computations were performed on two highly accurate full-dimensional H4 potential energy surfaces. It is found that for both potential surfaces, rotational quenching of HD from with concurrent rotational excitation of D2 from is the dominant transition with cross sections four times larger than that of elastically scattered D2 for the same quenching transition in HD. This process was not considered in the original analysis of the SARP experiments that probed ΔjHD = -2 transitions in HD(vHD = 1, jHD = 2) + D2 collisions. Cross sections are characterized by an l = 3 resonance for ortho-D2(jD2 = 0) collisions, while both l = 1 and l = 3 resonances are observed for the para-D2(jD2 = 1) partner. While our results are in excellent agreement with prior measurements of elastic and inelastic differential cross sections, the agreement is less satisfactory with the SARP experiments, in particular for the transition for which the theoretical calculations indicate that D2 rotational excitation channel is the dominant inelastic process.
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Affiliation(s)
- Bikramaditya Mandal
- Department of Chemistry and Biochemistry, University of Nevada, Las Vegas, Nevada 89154, USA.
| | - James F E Croft
- Department of Chemistry, Durham University, South Road, Durham, DH1 3LE, UK
| | - Pablo G Jambrina
- Departamento de Química Física, University of Salamanca, Salamanca 37008, Spain
| | - Hua Guo
- Department of Chemistry and Chemical Biology, University of New Mexico, Albuquerque, New Mexico 87131, USA
| | - F Javier Aoiz
- Departamento de Química Física, Universidad Complutense, Madrid 28040, Spain
| | - Naduvalath Balakrishnan
- Department of Chemistry and Biochemistry, University of Nevada, Las Vegas, Nevada 89154, USA.
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3
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Wang T, Yang T, Xiao C, Yang X. Vibration to Vibration: Product Energy Distribution of F + HD Crossed Molecular Beam Experiments. J Phys Chem A 2024; 128:3180-3185. [PMID: 38626324 DOI: 10.1021/acs.jpca.4c01523] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/18/2024]
Abstract
We investigated the F + HD(v = 1, j = 0) → HF + D reaction using the crossed molecular beam technique combined with the D atom Rydberg tagging time-of-flight spectroscopy. By detecting the products at various scattering angles for different collision energies in the range of 0.8-1.2 kcal/mol, we observed the forward-scattering products of HF(v' = 4) and determined the threshold energy for the opening of this reaction channel. Similar experiments were conducted for the F + HD(v = 0, j = 0) → HF + D reaction within the range of 1.1-1.6 kcal/mol, where forward-scattering products of HF(v' = 3) were observed, and the threshold energy for this reaction channel was determined as well. Furthermore, we measured the differential cross-sections for the F + HD → HF + D reaction in both the vibrational ground state and the excited state of HD and analyzed the vibrational quantum-state distribution of the HF products. It was found that the population of vibrational quantum states of the HF products increases synchronously with the excitation of the reactant HD vibrationally.
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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, Liaoning 116023, China
- Department of Chemistry, College of Science, Southern University of Science and Technology, Shenzhen, Guangdong 518055, China
| | - Tiangang Yang
- Department of Chemistry, College of Science, Southern University of Science and Technology, Shenzhen, Guangdong 518055, China
| | - Chunlei Xiao
- State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, Liaoning 116023, China
| | - Xueming Yang
- State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, Liaoning 116023, China
- Department of Chemistry, College of Science, Southern University of Science and Technology, Shenzhen, Guangdong 518055, China
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4
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Balakrishnan N, Jambrina PG, Croft JFE, Guo H, Aoiz FJ. Quantum stereodynamics of cold molecular collisions. Chem Commun (Camb) 2024; 60:1239-1256. [PMID: 38197484 DOI: 10.1039/d3cc04762h] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2024]
Abstract
Advances in quantum state preparations combined with molecular cooling and trapping technologies have enabled unprecedented control of molecular collision dynamics. This progress, achieved over the last two decades, has dramatically improved our understanding of molecular phenomena in the extreme quantum regime characterized by translational temperatures well below a kelvin. In this regime, collision outcomes are dominated by isolated partial waves, quantum threshold and quantum statistics effects, tiny energy splitting at the spin and hyperfine levels, and long-range forces. Collision outcomes are influenced not only by the quantum state preparation of the initial molecular states but also by the polarization of their rotational angular momentum, i.e., stereodynamics of molecular collisions. The Stark-induced adiabatic Raman passage technique developed in the last several years has become a versatile tool to study the stereodynamics of light molecular collisions in which alignment of the molecular bond axis relative to initial collision velocity can be fully controlled. Landmark experiments reported by Zare and coworkers have motivated new theoretical developments, including formalisms to describe four-vector correlations in molecular collisions that are revealed by the experiments. In this Feature article, we provide an overview of recent theoretical developments for the description of stereodynamics of cold molecular collisions and their implications to cold controlled chemistry.
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Affiliation(s)
- Naduvalath Balakrishnan
- Department of Chemistry and Biochemistry, University of Nevada, Las Vegas, Nevada 89154, USA.
| | - 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, New Zealand and Department of Physics, University of Otago, Dunedin, New Zealand
| | - Hua Guo
- Department of Chemistry and Chemical Biology, Center for Computational Chemistry, University of New Mexico, Albuquerque, New Mexico 87131, USA
| | - F Javier Aoiz
- Departamento de Química Física, Universidad Complutense, Madrid 28040, Spain
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5
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Xie Y, Han J, Wen L, Li Z, Xiao Y, Wang T, Yang X, Yang T. Enhanced Total Vibrational Excitation Yield in a Slow Narrow-Pulsed Hydrogen Molecular Beam. J Phys Chem Lett 2023; 14:11603-11609. [PMID: 38100090 DOI: 10.1021/acs.jpclett.3c03015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2023]
Abstract
High-efficiency excitation of a molecular beam is critical for investigating state-selected chemistry. However, achieving vibrational excitation of the entire beam for Raman-active molecules such as H2 proves extremely challenging, primarily because laser pulses are much shorter than the molecular beam. In this study, we achieve a total excitation efficiency of over 20% by employing stimulated Raman pumping (SRP) in a slow, narrow-pulsed molecular beam. Through optimizing the intensity and spot shape of the SRP lasers, we attain saturated excitation within the laser crossing region. Furthermore, by reducing the beam velocity and narrowing the beam pulse using a cold valve and a fast chopper, we significantly enhance the total excitation yield. COMSOL simulation and a newly developed model reveal that a critical velocity allows the chopper to block unexcited molecules and reserve most of the excited ones from the beam, resulting in the highest overall excitation yield. This innovative setup opens new possibilities for state-selected experiments in surface science and ion-molecule reaction dynamics, particularly involving weak transitions and pulsed lasers.
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Affiliation(s)
- Yurun Xie
- Shenzhen Key Laboratory of Energy Chemistry, Department of Chemistry, and Center for Advanced Light Source, Southern University of Science and Technology, Shenzhen, Guangdong 518055, China
- Institute of Advanced Science Facilities, Shenzhen, Guangdong 518107, China
| | - Jie Han
- Shenzhen Key Laboratory of Energy Chemistry, Department of Chemistry, and Center for Advanced Light Source, Southern University of Science and Technology, Shenzhen, Guangdong 518055, China
| | - Liping Wen
- Shenzhen Key Laboratory of Energy Chemistry, Department of Chemistry, and Center for Advanced Light Source, Southern University of Science and Technology, Shenzhen, Guangdong 518055, China
| | - Zhichao Li
- Shenzhen Key Laboratory of Energy Chemistry, Department of Chemistry, and Center for Advanced Light Source, Southern University of Science and Technology, Shenzhen, Guangdong 518055, China
| | - Yue Xiao
- Shenzhen Key Laboratory of Energy Chemistry, Department of Chemistry, and Center for Advanced Light Source, Southern University of Science and Technology, Shenzhen, Guangdong 518055, China
| | - Tao Wang
- Shenzhen Key Laboratory of Energy Chemistry, Department of Chemistry, and Center for Advanced Light Source, Southern University of Science and Technology, Shenzhen, Guangdong 518055, China
| | - Xueming Yang
- Shenzhen Key Laboratory of Energy Chemistry, Department of Chemistry, and Center for Advanced Light Source, Southern University of Science and Technology, Shenzhen, Guangdong 518055, China
- State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Science, Dalian, Liaoning 116023, China
- Hefei National Laboratory, Hefei, Anhui 230088, China
| | - Tiangang Yang
- Shenzhen Key Laboratory of Energy Chemistry, Department of Chemistry, and Center for Advanced Light Source, Southern University of Science and Technology, Shenzhen, Guangdong 518055, China
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6
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Croft JFE, Jambrina PG, Aoiz FJ, Guo H, Balakrishnan N. Cold Collisions of Ro-Vibrationally Excited D 2 Molecules. J Phys Chem A 2023; 127:1619-1627. [PMID: 36787203 DOI: 10.1021/acs.jpca.2c08855] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/15/2023]
Abstract
The H2 + H2 system has long been considered a benchmark system for ro-vibrational energy transfer in bimolecular collisions. However, most studies thus far have focused on collisions involving H2 molecules in the ground vibrational level or in the first excited vibrational state. While H2 + H2/HD collisions have received wide attention due to the important role they play in astrophysics, D2 + D2 collisions have received much less attention. Recently, Zhou et al. [ Nat. Chem. 2022, 14, 658-663, DOI: 10.1038/s41557-022-00926-z] examined stereodynamic aspects of rotational energy transfer in collisions of two aligned D2 molecules prepared in the v = 2 vibrational level and j = 2 rotational level. Here, we report quantum calculations of rotational and vibrational energy transfer in collisions of two D2 molecules prepared in vibrational levels up to v = 2 and identify key resonance features that contribute to the angular distribution in the experimental results of Zhou et al. The quantum scattering calculations were performed in full dimensionality and using the rigid-rotor approximation using a recently developed highly accurate six-dimensional potential energy surface for the H4 system that allows descriptions of collisions involving highly vibrationally excited H2 and its isotopologues.
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Affiliation(s)
- James F E Croft
- The Dodd-Walls Centre for Photonic and Quantum Technologies, Dunedin 9016, New Zealand.,Department of Physics, University of Otago, Dunedin 9016, New Zealand
| | - Pablo G Jambrina
- Departamento de Química Física, Universidad de Salamanca, Salamanca 37008, Spain
| | - F Javier Aoiz
- Departamento de Química Física, Universidad Complutense, Madrid 28040, Spain
| | - Hua Guo
- Department of Chemistry and Chemical Biology, University of New Mexico, Albuquerque, New Mexico 87131, United States
| | - N Balakrishnan
- Department of Chemistry and Biochemistry, University of Nevada, Las Vegas, Nevada 89154, United States
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7
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Yang D, Guo H, Xie D. Recent advances in quantum theory on ro-vibrationally inelastic scattering. Phys Chem Chem Phys 2023; 25:3577-3594. [PMID: 36602236 DOI: 10.1039/d2cp05069b] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Molecular collisions are of fundamental importance in understanding intermolecular interaction and dynamics. Its importance is accentuated in cold and ultra-cold collisions because of the dominant quantum mechanical nature of the scattering. We review recent advances in the time-independent approach to quantum mechanical characterization of non-reactive scattering in tetratomic systems, which is ideally suited for large collisional de Broglie wavelengths characteristic in cold and ultracold conditions. We discuss quantum scattering algorithms between two diatoms and between a triatom and an atom and their implementation, as well as various approximate schemes. They not only enable the characterization of collision dynamics in realistic systems but also serve as benchmarks for developing more approximate methods.
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Affiliation(s)
- Dongzheng Yang
- Department of Chemistry and Chemical Biology, University of New Mexico, Albuquerque, New Mexico 87131, USA.
| | - Hua Guo
- Department of Chemistry and Chemical Biology, University of New Mexico, Albuquerque, New Mexico 87131, USA.
| | - Daiqian Xie
- Institute of Theoretical and Computational Chemistry, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, China. .,Hefei National Laboratory, Hefei 230088, China
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8
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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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9
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Wang Y, Huang J, Wang W, Du T, Xie Y, Ma Y, Xiao C, Zhang Z, Zhang DH, Yang X. Stereodynamical control of the H + HD → H 2 + D reaction through HD reagent alignment. Science 2023; 379:191-195. [PMID: 36634162 DOI: 10.1126/science.ade7471] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Prealigning nonpolar reacting molecules leads to large stereodynamical effects because of their weak steering interaction en route to the reaction barrier. However, experimental limitations in preparing aligned molecules efficiently have hindered the investigation of steric effects in bimolecular reactions involving hydrogen. Here, we report a high-resolution crossed-beam study of the reaction H + HD(v = 1, j = 2) → H2(v', j') + D at collision energies of 0.50, 1.20, and 2.07 electron volts in which the vibrationally excited hydrogen deuteride (HD) molecules were prepared in two collision configurations, with their bond preferentially aligned parallel and perpendicular to the relative velocity of collision partners. Notable stereodynamical effects in differential cross sections were observed. Quantum dynamics calculations revealed that strong constructive interference in the perpendicular configuration plays an important role in the stereodynamical effects observed.
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Affiliation(s)
- Yufeng Wang
- State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, Liaoning 116023, China
| | - Jiayu Huang
- State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, Liaoning 116023, China
| | - Wei Wang
- State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, Liaoning 116023, China.,School of Chemical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Tianyu Du
- State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, Liaoning 116023, China.,School of Chemical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yurun Xie
- State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, Liaoning 116023, China.,Department of Chemistry and Shenzhen Key Laboratory of Energy Chemistry, Southern University of Science and Technology, Shenzhen 518055, China
| | - Yuxin Ma
- State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, Liaoning 116023, China.,School of Chemical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Chunlei Xiao
- State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, Liaoning 116023, China.,Hefei National Laboratory, Hefei 230088, China
| | - Zhaojun Zhang
- State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, Liaoning 116023, China
| | - Dong H Zhang
- State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, Liaoning 116023, China.,Department of Chemistry and Shenzhen Key Laboratory of Energy Chemistry, Southern University of Science and Technology, Shenzhen 518055, China.,Hefei National Laboratory, Hefei 230088, China
| | - Xueming Yang
- State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, Liaoning 116023, China.,Department of Chemistry and Shenzhen Key Laboratory of Energy Chemistry, Southern University of Science and Technology, Shenzhen 518055, China.,Hefei National Laboratory, Hefei 230088, China
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10
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Perreault WE, Zhou H, Mukherjee N, Zare RN. Coherent Preparation of Highly Vibrating and Rotating D 2 Molecules. J Phys Chem Lett 2022; 13:4682-4687. [PMID: 35605182 DOI: 10.1021/acs.jpclett.2c01209] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Highly vibrationally and rotationally excited hydrogen molecules are of immense interest for understanding and modeling the physics and chemistry of the cold interstellar medium. Using a sequence of two Stark-induced adiabatic Raman passages, we demonstrate the preparation of rotationally excited D2 molecules in the fourth excited vibrational level within its ground electronic state. The nearly complete population transfer to the target state is confirmed by observing both the threshold behavior as a function of the laser power and the depletion of the intermediate level. The vibrational excitation reported here opens new possibilities in the study of the much debated four-center reaction between a pair of hydrogen molecules. Additionally, these rovibrationally excited molecules could be potentially used to generate the high-intensity D- ion beams considered essential for D-T thermonuclear fusion by enhancing the cross section for dissociative electron attachment by 5 orders of magnitude compared to that of the ground state.
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Affiliation(s)
- William E Perreault
- Department of Chemistry, Stanford University, Stanford, California 94305, United States
| | - Haowen Zhou
- Department of Chemistry, Stanford University, Stanford, California 94305, United States
| | - Nandini Mukherjee
- Department of Chemistry, Stanford University, Stanford, California 94305, United States
| | - Richard N Zare
- Department of Chemistry, Stanford University, Stanford, California 94305, United States
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11
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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: 13] [Impact Index Per Article: 6.5] [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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12
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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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13
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da Silva H, Kendrick BK, Balakrishnan N. On the use of stereodynamical effects to control cold chemical reactions: The H + D2 ⟷ D + HD case study. J Chem Phys 2022; 156:044305. [DOI: 10.1063/5.0078168] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- H. da Silva
- Department of Chemistry and Biochemistry, University of Nevada, Las Vegas, Nevada 89154, USA
| | - B. K. Kendrick
- Theoretical Division (T-1, MS B221), Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - N. Balakrishnan
- Department of Chemistry and Biochemistry, University of Nevada, Las Vegas, Nevada 89154, USA
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14
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Abstract
Advances in atomic, molecular, and optical physics techniques allowed the cooling of simple molecules down to the ultracold regime ([Formula: see text]1 mK) and opened opportunities to study chemical reactions with unprecedented levels of control. This review covers recent developments in studying bimolecular chemistry at ultralow temperatures. We begin with a brief overview of methods for producing, manipulating, and detecting ultracold molecules. We then survey experimental works that exploit the controllability of ultracold molecules to probe and modify their long-range interactions. Further combining the use of physical chemistry techniques such as mass spectrometry and ion imaging significantly improved the detection of ultracold reactions and enabled explorations of their dynamics in the short range. We discuss a series of studies on the reaction KRb + KRb → K2 + Rb2 initiated below 1 [Formula: see text]K, including the direct observation of a long-lived complex, the demonstration of product rotational state control via conserved nuclear spins, and a test of the statistical model using the complete quantum state distribution of the products. Expected final online publication date for the Annual Review of Physical Chemistry, Volume 73 is April 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.
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Affiliation(s)
- Yu Liu
- Time and Frequency Division, National Institute of Standards and Technology, Boulder, Colorado 80305, USA; .,Department of Physics, University of Colorado, Boulder, Colorado 80309, USA
| | - Kang-Kuen Ni
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts 02138, USA; .,Harvard-Massachusetts Institute of Technology Center for Ultracold Atoms, Cambridge, Massachusetts 02138, USA
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15
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Zhou H, Perreault WE, Mukherjee N, Zare RN. Quantum mechanical double slit for molecular scattering. Science 2021; 374:960-964. [PMID: 34793222 DOI: 10.1126/science.abl4143] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
[Figure: see text].
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Affiliation(s)
- Haowen Zhou
- Department of Chemistry, Stanford University, Stanford, CA 94305, USA
| | | | - Nandini Mukherjee
- Department of Chemistry, Stanford University, Stanford, CA 94305, USA
| | - Richard N Zare
- Department of Chemistry, Stanford University, Stanford, CA 94305, USA
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16
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Zuo J, Croft JFE, Yao Q, Balakrishnan N, Guo H. Full-Dimensional Potential Energy Surface for Ro-vibrationally Inelastic Scattering between H 2 Molecules. J Chem Theory Comput 2021; 17:6747-6756. [PMID: 34677959 DOI: 10.1021/acs.jctc.1c00882] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We report a new full-dimensional potential energy surface (PES) for the inelastic scattering between ro-vibrationally excited H2 molecules. The new PES is based on 39,462 multi-reference configuration interaction points in dynamically relevant regions. The analytic form of the PES consists of a short-range term fit with the permutational invariant polynomial-neural network method and a long-range term with a physically correct asymptotic functional form accounting for both electrostatic and dispersion terms, which are connected smoothly with a switching function. The PES compares favorably with existing accurate PESs near the H2 equilibrium geometries but covers a much larger configuration space for H2 with up to 10 vibrational quanta. Full-dimensional quantum scattering calculations on the new PES reproduce the recent Stark-induced adiabatic Raman passage results for the HD(v = 1) + H2 scattering near 1 K, validating its accuracy. These calculations also revealed significant differences with existing PESs in describing scattering of vibrationally excited molecules, underscoring the ability of the new PES in handling such dynamics.
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Affiliation(s)
- Junxiang Zuo
- Department of Chemistry and Chemical Biology, University of New Mexico, Albuquerque, New Mexico 87131, United States
| | - James F E Croft
- The Dodd-Walls Centre for Photonic and Quantum Technologies, Dunedin, New Zealand and Department of Physics, University of Otago, Dunedin 9016, New Zealand
| | - Qian Yao
- Department of Chemistry and Chemical Biology, University of New Mexico, Albuquerque, New Mexico 87131, United States
| | - Naduvalath Balakrishnan
- Department of Chemistry and Biochemistry, University of Nevada, Las Vegas, Nevada 89154, United States
| | - Hua Guo
- Department of Chemistry and Chemical Biology, University of New Mexico, Albuquerque, New Mexico 87131, United States
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17
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Chen J, Li J, Bowman JM, Guo H. Energy transfer between vibrationally excited carbon monoxide based on a highly accurate six-dimensional potential energy surface. J Chem Phys 2020; 153:054310. [DOI: 10.1063/5.0015101] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Jun Chen
- Department of Chemistry and Chemical Biology, University of New Mexico, Albuquerque, New Mexico 87131, USA
| | - Jun Li
- School of Chemistry and Chemical Engineering, Chongqing University, Chongqing 401331, China
| | - Joel M. Bowman
- Department of Chemistry and Cherry L. Emerson Center for Scientific Computation, Emory University, Atlanta, Georgia 30322, USA
| | - Hua Guo
- Department of Chemistry and Chemical Biology, University of New Mexico, Albuquerque, New Mexico 87131, USA
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18
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Perreault WE, Zhou H, Mukherjee N, Zare RN. Harnessing the Power of Adiabatic Curve Crossing to Populate the Highly Vibrationally Excited H_{2} (v=7, j=0) Level. PHYSICAL REVIEW LETTERS 2020; 124:163202. [PMID: 32383909 DOI: 10.1103/physrevlett.124.163202] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/29/2020] [Accepted: 03/30/2020] [Indexed: 06/11/2023]
Abstract
A large ensemble of ∼10^{9} H_{2} (v=7, j=0) molecules is prepared in the collision-free environment of a supersonic beam by transferring nearly the entire H_{2} (v=0, j=0) ground-state population, where v and j are the vibrational and rotational quantum numbers, respectively. This is accomplished by controlling the crossing of the optically dressed adiabatic states using a pair of phase coherent laser pulses. The preparation of highly vibrationally excited H_{2} molecules opens new opportunities to test fundamental physical principles using two loosely bound yet entangled H atoms.
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Affiliation(s)
- William E Perreault
- Department of Chemistry, Stanford University, Stanford, California 94305, USA
| | - Haowen Zhou
- 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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Yao Q, Morita M, Xie C, Balakrishnan N, Guo H. Globally Accurate Full-Dimensional Potential Energy Surface for H 2 + HCl Inelastic Scattering. J Phys Chem A 2019; 123:6578-6586. [PMID: 31268323 DOI: 10.1021/acs.jpca.9b05958] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
A globally accurate full-dimensional potential energy surface (PES) for the inelastic scattering between H2 and HCl is developed on the basis of a large number of points calculated at the coupled-cluster singles, doubles, and perturbative triples level of theory. The machine-learned PES is trained with 42 417 ab initio points using the permutation invariant polynomial-neural network method, resulting in a root-mean-square fitting error of 5.6 cm-1. Both full- and reduced-dimensional quantum calculations for rotationally inelastic scattering are performed on this new PES and good agreement is obtained with previous quantum dynamical results on a reduced-dimensional model. Furthermore, strong resonances are identified at collision energies below 100 K, including cold conditions. This new PES provides a reliable platform for future studies of scattering dynamics with vibrationally excited collision partners in a wide range of collision energies extending to cold and ultracold conditions.
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Affiliation(s)
- Qian Yao
- Department of Chemistry and Chemical Biology , University of New Mexico , Albuquerque , New Mexico 87131 , United States
| | - Masato Morita
- Department of Chemistry and Biochemistry , University of Nevada , Las Vegas , Nevada 89154 , United States
| | - Changjian Xie
- Department of Chemistry and Chemical Biology , University of New Mexico , Albuquerque , New Mexico 87131 , United States
| | - Naduvalath Balakrishnan
- Department of Chemistry and Biochemistry , University of Nevada , Las Vegas , Nevada 89154 , United States
| | - Hua Guo
- Department of Chemistry and Chemical Biology , University of New Mexico , Albuquerque , New Mexico 87131 , United States
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20
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Jambrina PG, Menéndez M, Zanchet A, García E, Aoiz FJ. How reactant polarization can be used to change the effect of interference on reactive collisions. Phys Chem Chem Phys 2019; 21:14012-14022. [PMID: 30638224 DOI: 10.1039/c8cp06892e] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
It is common knowledge that integral and differential cross sections (DCSs) are strongly dependent on the spatial distribution of the molecular axis of the reactants. Hence, by controlling the axis distribution, it is possible to either promote or hinder the yield of products into specific final states or scattering angles. This idea has been successfully implemented in experiments by polarizing the internuclear axis before the reaction takes place, either by manipulating the rotational angular distribution or by the Stark effect in the presence of an orienting field. When there is a dominant reaction mechanism, characterized by a set of impact parameters and angles of attack, it is expected that a preparation that helps the system to reach the transition state associated with that mechanism will promote the reaction, whilst a different preparation would generally impair the reaction. However, when two or more competing mechanisms via interference contribute to the reaction into specific scattering angles and final states, it is not evident which would be the effect of changing the axis preparation. To address this problem, throughout this article we have simulated the effect that different experimental preparations have on the DCSs for the H + D2 reaction at relatively high energies, for which it has been shown that several competing mechanisms give rise to interference that shapes the DCS. To this aim, we have extended the formulation of the polarization dependent DCS to calculate polarization dependent generalized deflection functions of ranks greater than zero. Our results show that interference is very sensitive to changes in the internuclear axis preparation, and that the shape of the DCS can be controlled exquisitely.
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Affiliation(s)
- P G Jambrina
- Departamento de Química Física, Universidad de Salamanca, Salamanca, 37008, Spain.
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21
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Perreault WE, Mukherjee N, Zare RN. Stark-induced adiabatic Raman passage examined through the preparation of D 2 (v = 2, j = 0) and D 2 (v = 2, j = 2, m = 0). J Chem Phys 2019; 150:234201. [PMID: 31228886 DOI: 10.1063/1.5109261] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
We study the conditions that must be met for successful preparation of a large ensemble in a specific target quantum state using Stark-induced adiabatic Raman passage (SARP). In particular, we show that the threshold condition depends on the relative magnitudes of the Raman polarizability (r0v) and the difference of the optical polarizabilities (Δα00→vj) of the initial (v = 0, j = 0) and the target (v, j) rovibrational levels. Here, v and j are the vibrational and rotational quantum numbers, respectively. To illustrate how the operation of SARP is controlled by these two parameters, we experimentally prepared D2 (v = 2, j = 0) and D2 (v = 2, j = 2, m = 0) in a beam of D2 (v = 0, j = 0) molecules using a sequence of partially overlapping pump and Stokes laser pulses. By comparing theory and experiment, we were able to determine the Raman polarizability r02 ≈ 0.3 × 10-41 Cm/(V/m) and the difference polarizabilities Δα00→20 ≈ 1.4 × 10-41 Cm/(V/m) and Δα00→22 ≈ 3.4 × 10-41 Cm/(V/m) for the two Raman transitions. Our experimental data and theoretical calculations show that because the ratio r/Δα is larger for the (0,0) → (2,0) transition than the (0,0) → (2,2) transition, much less optical power is required to transfer a large population to the (v = 2, j = 0) level. Nonetheless, our experiment demonstrates that substantial population transfer to both the D2 (v = 2, j = 0) and D2 (v = 2, j = 2, m = 0) is achieved using appropriate laser fluences. Our derived threshold condition demonstrates that with increasing vibrational quantum number, it becomes more difficult to achieve large amounts of population transfer.
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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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22
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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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23
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Bohn JL, Rey AM, Ye J. Cold molecules: Progress in quantum engineering of chemistry and quantum matter. Science 2017; 357:1002-1010. [PMID: 28883071 DOI: 10.1126/science.aam6299] [Citation(s) in RCA: 135] [Impact Index Per Article: 19.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Cooling atoms to ultralow temperatures has produced a wealth of opportunities in fundamental physics, precision metrology, and quantum science. The more recent application of sophisticated cooling techniques to molecules, which has been more challenging to implement owing to the complexity of molecular structures, has now opened the door to the longstanding goal of precisely controlling molecular internal and external degrees of freedom and the resulting interaction processes. This line of research can leverage fundamental insights into how molecules interact and evolve to enable the control of reaction chemistry and the design and realization of a range of advanced quantum materials.
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Affiliation(s)
- John L Bohn
- JILA, National Institute of Standards and Technology and University of Colorado Boulder, Boulder, CO 80309-0440, USA.
| | - Ana Maria Rey
- JILA, National Institute of Standards and Technology and University of Colorado Boulder, Boulder, CO 80309-0440, USA.
| | - Jun Ye
- JILA, National Institute of Standards and Technology and University of Colorado Boulder, Boulder, CO 80309-0440, USA.
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24
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Moreno Carrascosa A, Northey T, Kirrander A. Imaging rotations and vibrations in polyatomic molecules with X-ray scattering. Phys Chem Chem Phys 2017; 19:7853-7863. [DOI: 10.1039/c6cp06793j] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
An approach for calculating elastic X-ray scattering from polyatomic molecules in specific electronic, vibrational, and rotational states is presented, and is used to consider the characterization of specific states in polyatomic molecules using elastic X-ray scattering.
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Affiliation(s)
| | - Thomas Northey
- EaStCHEM
- School of Chemistry
- University of Edinburgh
- EH9 3FJ Edinburgh
- UK
| | - Adam Kirrander
- EaStCHEM
- School of Chemistry
- University of Edinburgh
- EH9 3FJ Edinburgh
- UK
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25
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Northey T, Moreno Carrascosa A, Schäfer S, Kirrander A. Elastic X-ray scattering from state-selected molecules. J Chem Phys 2016; 145:154304. [PMID: 27782487 DOI: 10.1063/1.4962256] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The characterization of electronic, vibrational, and rotational states using elastic (coherent) X-ray scattering is considered. The scattering is calculated directly from complete active space self-consistent field level ab initio wavefunctions for H2 molecules in the ground-state X1Σg+ and first-excited EF1Σg+ electronic states. The calculated scattering is compared to recent experimental measurements [Y.-W. Liu et al., Phys. Rev. A 89, 014502 (2014)], and the influence of vibrational and rotational states on the observed signal is examined. The scaling of the scattering calculations with basis set is quantified, and it is found that energy convergence of the ab initio calculations is a good indicator of the quality of the scattering calculations.
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Affiliation(s)
- Thomas Northey
- EaStCHEM, School of Chemistry, University of Edinburgh, David Brewster Road, EH9 3FJ Edinburgh, United Kingdom
| | - Andrés Moreno Carrascosa
- EaStCHEM, School of Chemistry, University of Edinburgh, David Brewster Road, EH9 3FJ Edinburgh, United Kingdom
| | - Steffen Schäfer
- Aix-Marseille Université and Institut Matériaux Microélectronique Nanosciences de Provence (IM2NP), Marseille, France
| | - Adam Kirrander
- EaStCHEM, School of Chemistry, University of Edinburgh, David Brewster Road, EH9 3FJ Edinburgh, United Kingdom
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26
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Perreault WE, Mukherjee N, Zare RN. Preparation of a selected high vibrational energy level of isolated molecules. J Chem Phys 2016; 145:154203. [PMID: 27782486 DOI: 10.1063/1.4964938] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Stark induced adiabatic Raman passage (SARP) allows us to prepare an appreciable concentration of isolated molecules in a specific, high-lying vibrational level. The process has general applicability, and, as a demonstration, we transfer nearly 100 percent of the HD (v = 0, J = 0) in a supersonically expanded molecular beam of HD molecules to HD (v = 4, J = 0). This is achieved with a sequence of partially overlapping nanosecond pump (355 nm) and Stokes (680 nm) single-mode laser pulses of unequal intensities. By comparing our experimental data with our theoretical calculations, we are able to draw two important conclusions: (1) using SARP a large population (>1010 molecules per laser pulse) is prepared in the (v = 4, J = 0) level of HD and (2) the polarizability α00,40 (≅0.6 × 10-41 C m2 V-1) for the (v = 0, J = 0) to (v = 4, J = 0) Raman overtone transition is only about five times smaller than α00,10 for the (v = 0, J = 0) to (v = 1, J = 0) fundamental Raman transition. Moreover, the SARP process selects a specific rotational level in the vibrational manifold and can prepare one or a phased linear combination of magnetic sublevels (M states) within the selected vibrational-rotational level. This capability of preparing selected, highly excited vibrational levels of molecules under collision-free conditions opens new opportunities for fundamental scattering experiments.
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Affiliation(s)
- William E Perreault
- Department of Chemistry, Stanford University, Stanford, California 94305-5080, USA
| | - Nandini Mukherjee
- Department of Chemistry, Stanford University, Stanford, California 94305-5080, USA
| | - Richard N Zare
- Department of Chemistry, Stanford University, Stanford, California 94305-5080, USA
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27
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Yang T, Huang L, Wang T, Xiao C, Xie Y, Sun Z, Dai D, Chen M, Zhang D, Yang X. Effect of Reagent Vibrational Excitation on the Dynamics of F + H2(v = 1, j = 0) → HF(v′, j′) + H Reaction. J Phys Chem A 2015; 119:12284-90. [DOI: 10.1021/acs.jpca.5b06395] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Tiangang Yang
- Key
Laboratory of Materials Modification by Laser, Electron, and Ion Beams
(Ministry of Education), School of Physics and Optoelectronic Technology, Dalian University of Technology, Dalian, 116024 Liaoning, P. R. China
- State
Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of
Chemical Physics, Chinese Academy of Science, 457 Zhongshan Road, Dalian, 116023 Liaoning, P. R. China
| | - Long Huang
- State
Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of
Chemical Physics, Chinese Academy of Science, 457 Zhongshan Road, Dalian, 116023 Liaoning, P. R. China
| | - Tao Wang
- State
Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of
Chemical Physics, Chinese Academy of Science, 457 Zhongshan Road, Dalian, 116023 Liaoning, P. R. China
- Synergetic
Innovation Center of Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Chunlei Xiao
- State
Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of
Chemical Physics, Chinese Academy of Science, 457 Zhongshan Road, Dalian, 116023 Liaoning, P. R. China
| | - Yurun Xie
- State
Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of
Chemical Physics, Chinese Academy of Science, 457 Zhongshan Road, Dalian, 116023 Liaoning, P. R. China
| | - Zhigang Sun
- State
Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of
Chemical Physics, Chinese Academy of Science, 457 Zhongshan Road, Dalian, 116023 Liaoning, P. R. China
- Synergetic
Innovation Center of Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Dongxu Dai
- State
Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of
Chemical Physics, Chinese Academy of Science, 457 Zhongshan Road, Dalian, 116023 Liaoning, P. R. China
| | - Maodu Chen
- Key
Laboratory of Materials Modification by Laser, Electron, and Ion Beams
(Ministry of Education), School of Physics and Optoelectronic Technology, Dalian University of Technology, Dalian, 116024 Liaoning, P. R. China
| | - Donghui Zhang
- State
Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of
Chemical Physics, Chinese Academy of Science, 457 Zhongshan Road, Dalian, 116023 Liaoning, P. R. China
- Synergetic
Innovation Center of Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Xueming Yang
- State
Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of
Chemical Physics, Chinese Academy of Science, 457 Zhongshan Road, Dalian, 116023 Liaoning, P. R. China
- Synergetic
Innovation Center of Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
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28
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Aoiz FJ, Brouard M, Gordon SDS, Nichols B, Stolte S, Walpole V. A new perspective: imaging the stereochemistry of molecular collisions. Phys Chem Chem Phys 2015; 17:30210-28. [DOI: 10.1039/c5cp03273c] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The concept of the steric effect plays a central role in chemistry. This Perspective describes how the polarization of reactant molecules in space can be used to probe directly the steric effect, and highlights some of the new measurements that are made possible by coupling reactant orientation and alignment with ion imaging techniques.
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Affiliation(s)
- F. J. Aoiz
- Departamento de Química Física
- Facultad de Química
- Universidad Complutense
- 28040 Madrid
- Spain
| | - M. Brouard
- The Department of Chemistry
- University of Oxford
- The Physical and Theoretical Chemistry Laboratory
- Oxford
- UK
| | - S. D. S. Gordon
- The Department of Chemistry
- University of Oxford
- The Physical and Theoretical Chemistry Laboratory
- Oxford
- UK
| | - B. Nichols
- The Department of Chemistry
- University of Oxford
- The Physical and Theoretical Chemistry Laboratory
- Oxford
- UK
| | - S. Stolte
- Institute of Atomic and Molecular Physics
- Jilin University
- Changchun 130012
- China
- Department of Physics and Astronomy
| | - V. Walpole
- The Department of Chemistry
- University of Oxford
- The Physical and Theoretical Chemistry Laboratory
- Oxford
- UK
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29
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Deiss M, Drews B, Deissler B, Hecker Denschlag J. Probing the axis alignment of an ultracold spin-polarized Rb(2) molecule. PHYSICAL REVIEW LETTERS 2014; 113:233004. [PMID: 25526128 DOI: 10.1103/physrevlett.113.233004] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/04/2014] [Indexed: 06/04/2023]
Abstract
We present a novel method for probing the alignment of the molecular axis of an ultracold, nonpolar dimer. These results are obtained using diatomic ^{87}Rb_{2} molecules in the vibrational ground state of the lowest triplet potential a^{3}Σ_{u}^{+} trapped in a 3D optical lattice. We measure the molecular polarizabilities, which are directly linked to the alignment, along each of the x, y, and z directions of the lab coordinate system. By preparing the molecules in various, precisely defined rotational quantum states we can control the degree of alignment of the molecular axis with high precision over a large range. Furthermore, we derive the dynamical polarizabilities for a laser wavelength of 1064.5 nm parallel and orthogonal to the molecular axis of the dimer, α_{∥}=(8.9±0.9)×10^{3} a.u. and α_{⊥}=(0.9±0.4)×10^{3} a.u., respectively. Our findings highlight that the depth of an optical lattice strongly depends on the rotational state of the molecule, which has to be considered in collision experiments. The present work paves the way for reaction studies between aligned molecules in the ultracold temperature regime.
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Affiliation(s)
- Markus Deiss
- Institut für Quantenmaterie and Center for Integrated Quantum Science and Technology IQST, Universität Ulm, 89069 Ulm, Germany
| | - Björn Drews
- Institut für Quantenmaterie and Center for Integrated Quantum Science and Technology IQST, Universität Ulm, 89069 Ulm, Germany
| | - Benjamin Deissler
- Institut für Quantenmaterie and Center for Integrated Quantum Science and Technology IQST, Universität Ulm, 89069 Ulm, Germany
| | - Johannes Hecker Denschlag
- Institut für Quantenmaterie and Center for Integrated Quantum Science and Technology IQST, Universität Ulm, 89069 Ulm, Germany
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30
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Mukherjee N, Dong W, Zare RN. Coherent superposition of M-states in a single rovibrational level of H2 by Stark-induced adiabatic Raman passage. J Chem Phys 2014; 140:074201. [PMID: 24559344 DOI: 10.1063/1.4865131] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
We prepare an ensemble of isolated rovibrationally excited (v = 1, J = 2) H2 molecules in a phase-locked superposition of magnetic sublevels M using Stark-induced adiabatic Raman passage with linearly polarized single-mode pump (at 532 nm, ∼6 ns pulse duration, 200 mJ/pulse) and Stokes (699 nm, ∼4 ns pulse duration, 20 mJ/pulse) laser excitation. A biaxial superposition state, given by [line]ψ(t)⟩ = 1/√(2)[[line]ν = 1, J = 2, M = -2⟩ - [line]ν = 1, J = 2, M = +2⟩], is prepared with linearly but cross-polarized pump and Stokes laser pulses copropagating along the quantization z-axis. The degree of phase coherence is measured by using the O(2) line of the H2 E,F-X (0,1) band via 2 + 1 resonance enhanced multiphoton ionization (REMPI) at 210.8 nm by recording interference fringes in the REMPI signal in a time-of-flight mass spectrometer as the direction of the UV laser polarization is rotated using a half-wave plate. Nearly 60% population transfer from H2 (v = 0, J = 0) ground state to the superposition state in H2 (v = 1, J = 2) is measured from the depletion of the Q(0) line of the E,F-X (0,0) band as the Stokes frequency is tuned across the (v = 0, J = 0) → (v = 1, J = 2) Raman resonance.
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Affiliation(s)
- Nandini Mukherjee
- Department of Chemistry, Stanford University, Stanford, California 94305-5080, USA
| | - Wenrui Dong
- Department of Chemistry, Stanford University, Stanford, California 94305-5080, USA
| | - Richard N Zare
- Department of Chemistry, Stanford University, Stanford, California 94305-5080, USA
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31
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Wang T, Chen J, Yang T, Xiao C, Sun Z, Huang L, Dai D, Yang X, Zhang DH. Dynamical Resonances Accessible Only by Reagent Vibrational Excitation in the F + HD→HF + D Reaction. Science 2013; 342:1499-502. [DOI: 10.1126/science.1246546] [Citation(s) in RCA: 95] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Affiliation(s)
- Tao Wang
- State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, Liaoning, China
| | - Jun Chen
- State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, Liaoning, China
| | - Tiangang Yang
- State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, Liaoning, China
| | - Chunlei Xiao
- State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, Liaoning, China
| | - Zhigang Sun
- State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, Liaoning, China
| | - Long Huang
- State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, Liaoning, China
| | - Dongxu Dai
- State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, Liaoning, China
| | - Xueming Yang
- State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, Liaoning, China
- Center for Advanced Chemical Physics, University of Science and Technology of China, 96 Jinzhai Road, Hefei 230026, P. R. China
| | - Dong H. Zhang
- State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, Liaoning, China
- Center for Advanced Chemical Physics, University of Science and Technology of China, 96 Jinzhai Road, Hefei 230026, P. R. China
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Herráez-Aguilar D, Jambrina PG, Aldegunde J, Sáez-Rábanos V, de Miranda MP, Aoiz FJ. The reactive collision mechanism evinced: stereodynamical control of the elementary Br + H2 → H + HBr reaction. Phys Chem Chem Phys 2013; 15:13513-22. [PMID: 23823942 DOI: 10.1039/c3cp51271a] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
From a kinetics standpoint, reactive molecular collisions are the building blocks of the mechanisms of chemical reactions. In contrast, a dynamics standpoint reveals molecular collisions to have their own internal mechanisms, which are not mere theoretical abstractions: through suitable preparation of the reactants internal and stereochemical states, features of the mechanisms of a reactive molecular collision can be made evident and used as "handles" to control the reaction outcome. Using time-independent quantum dynamical calculations, we demonstrate this for the Br + H2(v = 0-1, j = 2) → H + HBr reaction in the 1.0-1.6 eV range of total energies. Despite its pronounced effect on reactivity, which is in agreement with the predictions from Polanyi rules, reactant vibration is found to have little effect on the mechanism of this endoergic, late-barrier reaction. Analysis of the correlations between directional reaction properties shows that the collision stereochemistry strongly depends on the total energy, but not on how this energy is partitioned between reactant translation and vibration. The stereodynamical preferences implied by the collision mechanisms determine how and to what extent one can control the reaction. Regarding the overall reaction, the extent of control is found to be large near the reaction threshold but not when the total energy is high. Regarding state-to-state reactions, the effect of reactant stereochemistry on the product rotational state distribution is found to be nontrivial and energy dependent.
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Affiliation(s)
- D Herráez-Aguilar
- Departamento de Quimica Fisica I, Facultad de Quimica, Universidad Complutense de Madrid, 28040, Spain
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Dong W, Mukherjee N, Zare RN. Optical preparation of H2 rovibrational levels with almost complete population transfer. J Chem Phys 2013; 139:074204. [DOI: 10.1063/1.4818526] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Mukherjee N, Dong W, Harrison JA, Zare RN. Communication: Transfer of more than half the population to a selected rovibrational state of H2 by Stark-induced adiabatic Raman passage. J Chem Phys 2013; 138:051101. [DOI: 10.1063/1.4790402] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Wang T, Yang T, Xiao C, Dai D, Yang X. Highly Efficient Pumping of Vibrationally Excited HD Molecules via Stark-Induced Adiabatic Raman Passage. J Phys Chem Lett 2013; 4:368-371. [PMID: 26281725 DOI: 10.1021/jz302103u] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
A primary prerequisite to study reactivity of vibrationally excited species is to efficiently prepare reacting species in a well-defined vibrational level. Efficient pumping of IR active vibrational modes in a molecule can be achieved by direct IR absorption. For vibrational modes that are only Raman active, however, efficient preparation of vibrationally excited states in those modes is not easily attainable. In this work, we have shown that highly efficient preparation of the HD(v = 1) state using the Stark-induced adiabatic Raman passage (SARP) scheme is feasible. As high as 91% population transfer from v = 0 to 1 of HD has been demonstrated in our experiment. This method provides new opportunities for future experimental studies on the dynamics of vibrational state molecules, especially H2, in both gas-phase and beam-surface reactions.
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Affiliation(s)
- Tao Wang
- †State key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road Dalian 116023, China
| | - Tiangang Yang
- †State key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road Dalian 116023, China
- ‡School of Physics and Optoelectric Engineering, Dalian University of Technology, Dalian, Liaoning 116023, China
| | - Chunlei Xiao
- †State key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road Dalian 116023, China
| | - Dongxu Dai
- †State key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road Dalian 116023, China
| | - Xueming Yang
- †State key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road Dalian 116023, China
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Wang T, Yang T, Xiao C, Dai D, Yang X. Efficient Coherent Population Transfer of D2 Molecules by Stark‐Induced Adiabatic Raman Passage. CHINESE J CHEM PHYS 2013. [DOI: 10.1063/1674-0068/26/01/8-12] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
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Mukherjee N, Zare RN. Can stimulated Raman pumping cause large population transfers in isolated molecules? J Chem Phys 2011; 135:184202. [DOI: 10.1063/1.3657832] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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