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Zou J, Gordon SDS, Osterwalder A. Sub-Kelvin Stereodynamics of the Ne(^{3}P_{2})+N_{2} Reaction. PHYSICAL REVIEW LETTERS 2019; 123:133401. [PMID: 31697548 DOI: 10.1103/physrevlett.123.133401] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/18/2019] [Indexed: 06/10/2023]
Abstract
We present an experimental study of the low-energy stereodynamics of the Ne(^{3}P_{2})+N_{2} reaction. Supersonic expansions of the two reactants are superposed in a merged beam experiment, where individual velocity control of the two beams allows us to reach average relative velocities of zero, yielding minimum collision energies around 60 mK. We combine the merged beam technique with the orientation of the metastable neon atoms and measure the branching between two reaction channels, Penning ionization and associative ionization, as a function of neon orientation and collision energy, covering the range 0.06-700 K. We find that we lose the ability to orient Ne below ≈100 K due to dynamic reorientation. Associative ionization products Ne-N_{2}^{+} predissociate with a probability of 30%-60% and that associative ionization is entirely due to reactions of the Ω=2 state, where the singly occupied p orbital of the Ne^{*} is oriented along the interatomic axis.
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Affiliation(s)
- Junwen Zou
- Institute for Chemical Sciences and Engineering, Ecole Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland
| | - Sean D S Gordon
- Institute for Chemical Sciences and Engineering, Ecole Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland
| | - Andreas Osterwalder
- Institute for Chemical Sciences and Engineering, Ecole Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland
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52
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Li J, Kais S. Entanglement classifier in chemical reactions. SCIENCE ADVANCES 2019; 5:eaax5283. [PMID: 31414049 PMCID: PMC6677555 DOI: 10.1126/sciadv.aax5283] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/31/2019] [Accepted: 06/24/2019] [Indexed: 06/10/2023]
Abstract
The Einstein, Podolsky, and Rosen (EPR) entanglement, which features the essential difference between classical and quantum physics, has received wide theoretical and experimental attentions. Recently, the desire to understand and create quantum entanglement between particles such as spins, photons, atoms, and molecules is fueled by the development of quantum teleportation, quantum communication, quantum cryptography, and quantum computation. Although most of the work has focused on showing that entanglement violates the famous Bell's inequality and its generalization for discrete measurements, few recent attempts focus on continuous measurement results. Here, we have developed a general practical inequality to test entanglement for continuous measurement results, particularly scattering of chemical reactions. After we explain how to implement this inequality to classify entanglement in scattering experiments, we propose a specific chemical reaction to test the violation of this inequality. The method is general and could be used to classify entanglement for continuous measurement results.
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Affiliation(s)
- Junxu Li
- Department of Chemistry, Department of Physics and Astronomy, and Birck Nanotechnology Center, Purdue University, West Lafayette, IN 47907, USA
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53
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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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54
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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: 26] [Impact Index Per Article: 5.2] [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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55
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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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56
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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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57
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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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58
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Croft JFE, Balakrishnan N. Controlling rotational quenching rates in cold molecular collisions. J Chem Phys 2019; 150:164302. [PMID: 31042924 DOI: 10.1063/1.5091576] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The relative orientation and alignment of colliding molecules plays a key role in determining the rates of chemical processes. Here, we examine in detail a prototypical example: rotational quenching of HD in cold collisions with H2. We show that the rotational quenching rate from j = 2 → 0, in the v = 1 vibrational level, can be maximized by aligning the HD along the collision axis and can be minimized by aligning the HD at the so called magic angle. This follows from quite general helicity considerations and suggests that quenching rates for other similar systems can also be controlled in this manner.
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Affiliation(s)
- J F E Croft
- The Dodd Walls Centre for Photonic and Quantum Technologies, Dunedin, New Zealand
| | - N Balakrishnan
- Department of Chemistry and Biochemistry, University of Nevada, Las Vegas, Nevada 89154, USA
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59
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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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60
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Croft JFE, Balakrishnan N, Huang M, Guo H. Unraveling the Stereodynamics of Cold Controlled HD-H_{2} Collisions. PHYSICAL REVIEW LETTERS 2018; 121:113401. [PMID: 30265091 DOI: 10.1103/physrevlett.121.113401] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/29/2018] [Indexed: 06/08/2023]
Abstract
Measuring inelastic rates with partial-wave resolution requires temperatures close to a Kelvin or below, even for the lightest molecule. In a recent experiment, Perreault, Mukherjee, and Zare [Nat. Chem. 10, 561 (2018).NCAHBB1755-433010.1038/s41557-018-0028-5] studied collisional relaxation of excited HD molecules in the v=1, j=2 state by para- and ortho-H_{2} at a temperature of about 1 K, extracting the angular distribution of scattered HD in the v=1, j=0 state. By state preparation of the HD molecules, control of the angular distribution of scattered HD was demonstrated. Here, we report a first-principles simulation of that experiment which enables us to attribute the main features of the observed angular distribution to a single L=2 partial-wave shape resonance. Our results demonstrate important stereodynamical insights that can be gained when numerically exact quantum scattering calculations are combined with experimental results in the few-partial-wave regime.
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Affiliation(s)
- James F E Croft
- 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
| | - Meng Huang
- 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
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