1
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Jambrina PG, Croft JFE, Balakrishnan N, Guo H, Aoiz FJ. Determination of collision mechanisms at low energies using four-vector correlations. Faraday Discuss 2024; 251:104-124. [PMID: 38836438 DOI: 10.1039/d3fd00173c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/06/2024]
Abstract
In molecular dynamics, a fundamental question is how the outcome of a collision depends on the relative orientation of the collision partners before their interaction begins (the stereodynamics of the process). The preference for a particular orientation of the reactant complex is intimately related to the idea of a collision mechanism and the possibility of control, as revealed in recent experiments. Indeed, this preference holds not only for chemical reactions involving complex polyatomic molecules, but also for the simplest inelastic atom-diatom collisions at cold collision energies. In this work, we report how the outcome of rotationally inelastic collisions between two D2 molecules can be controlled by changing the alignment of their internuclear axes under the same or different polarization vectors. Our results demonstrate that a higher degree of control can be achieved when two internuclear axes are aligned, especially when both molecules are relaxed in the collision. The possibility of control extends to very low energies, even to the ultracold regime, when no control could be achieved just by the alignment of the internuclear axis of one of the colliding partners.
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Affiliation(s)
- P G Jambrina
- Departamento de Química Física, Universidad de Salamanca, Salamanca 37008, Spain.
| | - J F E Croft
- Department of Chemistry, Durham University, Durham, DH1 3LE, UK.
| | - N Balakrishnan
- Department of Chemistry and Biochemistry, University of Nevada, Las Vegas, Nevada 89154, USA.
| | - Hua Guo
- Department of Chemistry and Chemical Biology, University of New Mexico, Albuquerque, New Mexico 87131, USA.
| | - F J Aoiz
- Departamento de Química Física, Universidad Complutense, Madrid 28040, Spain.
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2
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Jambrina PG, Croft JFE, Zuo J, Guo H, Balakrishnan N, Aoiz FJ. Stereodynamical Control of Cold Collisions between Two Aligned D_{2} Molecules. PHYSICAL REVIEW LETTERS 2023; 130:033002. [PMID: 36763383 DOI: 10.1103/physrevlett.130.033002] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/24/2022] [Revised: 09/25/2022] [Accepted: 12/21/2022] [Indexed: 06/18/2023]
Abstract
Resonant scattering of optically state-prepared and aligned molecules in the cold regime allows the most detailed interrogation and control of bimolecular collisions. This technique has recently been applied to collisions of two aligned ortho-D_{2} molecules prepared in the j=2 rotational level of the v=2 vibrational manifold using the Stark-induced adiabatic Raman passage technique. Here, we develop the theoretical formalism for describing four-vector correlations in collisions of two aligned molecules and apply our approach to state-prepared D_{2}(v=2,j=2)+D_{2}(v=2,j=2)→D_{2}(v=2,j=2)+D_{2}(v=2,j=0) collisions, making possible the simulations of the experimental results from first principles. Key features of the experimental angular distributions are reproduced and attributed primarily to a partial wave resonance with orbital angular momentum ℓ=4.
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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
| | - Junxiang Zuo
- 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
| | - 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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3
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Tang G, Besemer M, Onvlee J, Karman T, van der Avoird A, Groenenboom GC, van de Meerakker SYT. Correlated rotational excitations in NO–CO inelastic collisions. J Chem Phys 2022; 156:214304. [DOI: 10.1063/5.0092561] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
We present a joint experimental and theoretical study of rotationally inelastic collisions between NO ( X2Π1/2, ν = 0, j = 1/2, f) radicals and CO ( X1Σ+, ν = 0, j = 0) molecules at a collision energy of 220 cm−1. State-to-state scattering images for excitation of NO radicals into various final states were measured with high resolution by combining the Stark deceleration and velocity map imaging techniques. The high image resolution afforded the observation of correlated rotational excitations of NO–CO pairs, which revealed a number of striking scattering phenomena. The so-called “parity-pair” transitions in NO are found to have similar differential cross sections, independent of the concurrent excitation of CO, extending this well-known effect for collisions between NO and rare gas atoms into the realm of bimolecular collisions. Forward scattering is found for collisions that induce a large amount of rotational energy transfer (in either NO, CO, or both), which require low impact parameters to induce sufficient energy transfer. This observation is interpreted in terms of the recently discovered hard collision glory scattering mechanism, which predicts the forward bending of initially backward receding trajectories if the energy uptake in the collision is substantial in relation to the collision energy. The experimental results are in good agreement with the predictions from coupled-channels quantum scattering calculations based on an ab initio NO–CO potential energy surface.
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Affiliation(s)
- Guoqiang Tang
- Institute for Molecules and Materials, Radboud University, Heyendaalseweg 135, 6525 AJ Nijmegen, The Netherlands
| | - Matthieu Besemer
- Institute for Molecules and Materials, Radboud University, Heyendaalseweg 135, 6525 AJ Nijmegen, The Netherlands
| | - Jolijn Onvlee
- Institute for Molecules and Materials, Radboud University, Heyendaalseweg 135, 6525 AJ Nijmegen, The Netherlands
| | - Tijs Karman
- Institute for Molecules and Materials, Radboud University, Heyendaalseweg 135, 6525 AJ Nijmegen, The Netherlands
| | - Ad van der Avoird
- Institute for Molecules and Materials, Radboud University, Heyendaalseweg 135, 6525 AJ Nijmegen, The Netherlands
| | - Gerrit C. Groenenboom
- Institute for Molecules and Materials, Radboud University, Heyendaalseweg 135, 6525 AJ Nijmegen, The Netherlands
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4
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Jambrina PG, Morita M, Croft JFE, Aoiz FJ, Balakrishnan N. Role of Low Energy Resonances in the Stereodynamics of Cold He + D 2 Collisions. J Phys Chem Lett 2022; 13:4064-4072. [PMID: 35499484 DOI: 10.1021/acs.jpclett.2c00587] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
In recent experiments using the Stark-induced adiabatic Raman passage technique, Zhou et al. ( J. Chem. Phys. 2021, 154, 104309; Science 2021, 374, 960-964) measured the product's angular distribution for the collisions between He and aligned D2 molecules at cold collision energies. The signatures of the angular distributions were attributed to an [Formula: see text] = 2 resonance that governs scattering at low energies. A first-principles quantum mechanical treatment of this problem is presented here using a highly accurate interaction potential for the He-H2 system. Our results predict a very intense [Formula: see text] = 1 resonance at low energies, leading to angular distributions that differ from those measured in the experiment. A good agreement with the experiment is achieved only when the [Formula: see text] = 1 resonance is artificially removed, for example, by excluding the lowest energies present in the experimental velocity distribution. Our analysis revealed that neither the position nor the intensity of the [Formula: see text] = 1 resonance significantly changes when the interaction potential is modified within its predicted uncertainties. Energy-resolved measurements may help to resolve the discrepancy.
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Affiliation(s)
- Pablo G Jambrina
- Departamento de Química Física, University of Salamanca, Salamanca 37008, Spain
| | - Masato Morita
- Department of Chemistry and Biochemistry, University of Nevada, Las Vegas, Nevada 89154, United States
| | - James F E Croft
- Department of Physics, University of Otago, Dunedin 9054, New Zealand
- Dodd-Walls Centre for Photonic and Quantum Technologies, Dunedin 9054, New Zealand
| | - 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, United States
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5
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Tang G, Besemer M, de Jongh T, Shuai Q, van der Avoird A, Groenenboom GC, van de Meerakker SYT. Correlations in rotational energy transfer for NO-D 2 inelastic collisions. J Chem Phys 2020; 153:064301. [PMID: 35287454 DOI: 10.1063/5.0019472] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
We present a combined experimental and theoretical study of state-to-state inelastic collisions between NO (X 2Π1/2, j = 1/2, f) radicals and D2 (j = 0, 1, 2, 3) molecules at collision energies of 100 cm-1 and 750 cm-1. Using the combination of Stark deceleration and velocity map imaging, we fully resolve pair-correlated excitations in the scattered molecules. Both spin-orbit conserving and spin-orbit changing transitions in the NO radical are measured, while the coincident rotational excitation (j = 0 → j = 2) and rotational de-excitation (j = 2 → j = 0 and j = 3 → j = 1) in D2 are observed. De-excitation of D2 shows a strong dependence on the spin-orbit excitation of NO. We observe translation-to-rotation energy transfer as well as direct rotation-to-rotation energy transfer at the lowest collision energy probed. The experimental results are in good agreement with cross sections obtained from quantum coupled-channels calculations based on recent NO-D2 potential energy surfaces. The observed trends in the correlated scattering cross sections are understood in terms of the NO-D2 quadrupole-quadrupole interaction.
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Affiliation(s)
- Guoqiang Tang
- Institute for Molecules and Materials, Radboud University, Heyendaalseweg 135, 6525 AJ Nijmegen, The Netherlands
| | - Matthieu Besemer
- Institute for Molecules and Materials, Radboud University, Heyendaalseweg 135, 6525 AJ Nijmegen, The Netherlands
| | - Tim de Jongh
- Institute for Molecules and Materials, Radboud University, Heyendaalseweg 135, 6525 AJ Nijmegen, The Netherlands
| | - Quan Shuai
- Institute for Molecules and Materials, Radboud University, Heyendaalseweg 135, 6525 AJ Nijmegen, The Netherlands
| | - Ad van der Avoird
- Institute for Molecules and Materials, Radboud University, Heyendaalseweg 135, 6525 AJ Nijmegen, The Netherlands
| | - Gerrit C Groenenboom
- Institute for Molecules and Materials, Radboud University, Heyendaalseweg 135, 6525 AJ Nijmegen, The Netherlands
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6
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Brouard M, Chadwick H, Gordon SDS, Heid CG, Hornung B, Nichols B, Kłos J, Jambrina PG, Aoiz FJ. Differential cross sections and collision-induced rotational alignment in inelastic scattering of NO(X) by Xe. CHINESE J CHEM PHYS 2020. [DOI: 10.1063/1674-0068/cjcp2002020] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Affiliation(s)
- Mark Brouard
- The Department of Chemistry, University of Oxford, The Chemistry Research Laboratory, 12 Mansfield Road, Oxford OX1 3TA, UK
| | - Helen Chadwick
- The Department of Chemistry, University of Oxford, The Chemistry Research Laboratory, 12 Mansfield Road, Oxford OX1 3TA, UK
| | - Sean D. S. Gordon
- The Department of Chemistry, University of Oxford, The Chemistry Research Laboratory, 12 Mansfield Road, Oxford OX1 3TA, UK
| | - Cornelia G. Heid
- The Department of Chemistry, University of Oxford, The Chemistry Research Laboratory, 12 Mansfield Road, Oxford OX1 3TA, UK
| | - Balazs Hornung
- The Department of Chemistry, University of Oxford, The Chemistry Research Laboratory, 12 Mansfield Road, Oxford OX1 3TA, UK
| | - Bethan Nichols
- The Department of Chemistry, University of Oxford, The Chemistry Research Laboratory, 12 Mansfield Road, Oxford OX1 3TA, UK
| | - Jacek Kłos
- Department of Chemistry and Biochemistry, University of Maryland, College Park, Maryland 20742, USA
| | - Pablo G. Jambrina
- Departamento de Química Física, Facultad de Ciencias Químicas, University of Salamanca, Salamanca, Spain
| | - F. Javier Aoiz
- Departamento de Química Física, Facultad de Química, Universidad Complutense, 28040 Madrid, Spain
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7
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Affiliation(s)
- Sean D. S. Gordon
- Institute for Chemical Sciences and Engineering (ISIC), Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
- Present address: EPFL Innovation Park, Building C, 1015 Lausanne, Switzerland
| | - Andreas Osterwalder
- Institute for Chemical Sciences and Engineering (ISIC), Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
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8
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Walpole V, Heid CG, Jambrina PG, Aoiz FJ, Brouard M. Steric Effects in the Inelastic Scattering of NO(X) + Ar: Side-on Orientation. J Phys Chem A 2019; 123:8787-8806. [PMID: 31513425 DOI: 10.1021/acs.jpca.9b07264] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The rotationally inelastic collisions of NO(X) with Ar, in which the NO bond-axis is oriented side-on (i.e., perpendicular) to the incoming collision partner, are investigated experimentally and theoretically. The NO(X) molecules are selected in the |j = 0.5, Ω = 0.5, ε = -1, f⟩ state prior to bond-axis orientation in a static electric field. The scattered NO products are then state selectively detected using velocity-map ion imaging. The experimental bond-axis orientation resolved differential cross sections and integral steric asymmetries are compared with quantum mechanical calculations, and are shown to be in good agreement. The strength of the orientation field is shown to affect the structure observed in the differential cross sections, and to some extent also the steric preference, depending on the ratio of the initial e and f Λ-doublets in the superposition determined by the orientation field. Classical and quantum calculations are compared and used to rationalize the structures observed in the differential cross sections. It is found that these structures are due to quantum mechanical interference effects, which differ for the two possible orientations of the NO molecule due to the anisotropy of the potential energy surface probed in the side-on orientation. Side-on collisions are shown to maximize and afford a high degree of control over the scattering intensity at small scattering angles (θ < 90°), while end-on collisions are predicted to dominate in the backward scattered region (θ > 90°).
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Affiliation(s)
- Victoria Walpole
- The Department of Chemistry , University of Oxford, Chemistry Research Laboratory , 12 Mansfield Road , Oxford OX1 3TA , U.K
| | - Cornelia G Heid
- The Department of Chemistry , University of Oxford, Chemistry Research Laboratory , 12 Mansfield Road , Oxford OX1 3TA , U.K
| | - Pablo G Jambrina
- Departamento de Química Física , Universidad de Salamanca , 37008 , Salamanca , Spain
| | - F Javier Aoiz
- Departamento de Química Física, Facultad de Química , Universidad Complutense , 28040 Madrid , Spain
| | - Mark Brouard
- The Department of Chemistry , University of Oxford, Chemistry Research Laboratory , 12 Mansfield Road , Oxford OX1 3TA , U.K
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9
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Gao Z, Loreau J, van der Avoird A, van de Meerakker SYT. Direct observation of product-pair correlations in rotationally inelastic collisions of ND 3 with D 2. Phys Chem Chem Phys 2019; 21:14033-14041. [PMID: 30649107 DOI: 10.1039/c8cp07109h] [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
We present a combined experimental and theoretical study of state-to-state inelastic scattering of ND3(j = 11-) with D2 (j = 0, 1, 2, 3) molecules at collision energies around 800 cm-1. Using a crossed molecular beam apparatus which employs the combination of Stark deceleration and velocity map imaging, we observe the correlated rotational excitations of both collision partners. For D2, both elastic (ΔjD2 = 0), inelastic excitation (j = 0 →j = 2) and inelastic de-excitation (j = 2 →j = 0) processes are observed. For a number of final ND3 states, inelastic channels in which D2 is rotationally excited or de-excited appear surprisingly strong. The experimental results are in excellent agreement with the predictions from quantum scattering calculations which are based on an ab initio ND3-D2 potential energy surface.
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Affiliation(s)
- Zhi Gao
- Institute for Molecules and Materials, Radboud University, Heyendaalseweg 135, 6525 AJ Nijmegen, The Netherlands.
| | - Jérôme Loreau
- Service de Chimie Quantique et Photophysique, Université libre de Bruxelles, CP 160/09, 1050 Brussels, Belgium.
| | - Ad van der Avoird
- Institute for Molecules and Materials, Radboud University, Heyendaalseweg 135, 6525 AJ Nijmegen, The Netherlands.
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10
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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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11
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Sun ZF, Bishwakarma CK, Song L, van der Avoird A, van Hemert MC, Suits AG, McBane GC, Parker DH. Imaging inelastic scattering of CO with argon: polarization dependent differential cross sections. Phys Chem Chem Phys 2019; 21:9200-9211. [DOI: 10.1039/c9cp00876d] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Rotationally inelastic scattering of carbon monoxide (CO) with argon at a collision energy of 700 cm−1 has been investigated by measuring polarization dependent differential scattering cross sections (PDDCSs) for rotationally excited CO molecules using a crossed molecular beam apparatus coupled with velocity-map ion imaging.
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Affiliation(s)
- Zhong-Fa Sun
- Department of Molecular and Laser Physics
- Institute for Molecules and Materials
- Radboud University
- 6525 AJ Nijmegen
- The Netherlands
| | - Chandan K. Bishwakarma
- Department of Molecular and Laser Physics
- Institute for Molecules and Materials
- Radboud University
- 6525 AJ Nijmegen
- The Netherlands
| | - Lei Song
- Theoretical Chemistry
- Institute for Molecules and Materials
- Radboud University
- 6525 AJ Nijmegen
- The Netherlands
| | - Ad van der Avoird
- Theoretical Chemistry
- Institute for Molecules and Materials
- Radboud University
- 6525 AJ Nijmegen
- The Netherlands
| | - Marc C. van Hemert
- Leiden Institute of Chemistry
- Gorlaeus Laboratories
- Leiden University
- 2333 CC Leiden
- The Netherlands
| | - Arthur G. Suits
- Department of Chemistry
- University of Missouri
- Columbia MO 65211
- USA
| | - George C. McBane
- Department of Chemistry
- Grand Valley State University
- Allendale
- USA
| | - David H. Parker
- Department of Molecular and Laser Physics
- Institute for Molecules and Materials
- Radboud University
- 6525 AJ Nijmegen
- The Netherlands
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12
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Sharples TR, Leng JG, Luxford TFM, McKendrick KG, Jambrina PG, Aoiz FJ, Chandler DW, Costen ML. Non-intuitive rotational reorientation in collisions of NO(A 2Σ+) with Ne from direct measurement of a four-vector correlation. Nat Chem 2018; 10:1148-1153. [DOI: 10.1038/s41557-018-0121-9] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2017] [Accepted: 07/12/2018] [Indexed: 11/09/2022]
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13
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Gao Z, Karman T, Tang G, van der Avoird A, Groenenboom GC, van de Meerakker SYT. Correlated energy transfer in rotationally and spin-orbit inelastic collisions of NO(X 2Π 1/2, j = 1/2f) with O 2(X 3Σ g-). Phys Chem Chem Phys 2018; 20:12444-12453. [PMID: 29697730 DOI: 10.1039/c8cp01784k] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We present a combined experimental and theoretical study of state-to-state inelastic scattering of NO(X2Π1/2, j = 1/2f) with O2(X3Σg-) molecules at a collision energy of 480 cm-1, focusing in particular on the observation and interpretation of correlated excitations in both NO and O2. Various final states of the NO radical, in both spin-orbit manifolds, were measured with high resolution using a crossed molecular beam apparatus which employs a combination of Stark deceleration and velocity map imaging. Velocity map imaging directly measures both the angular distribution and the radial velocity distribution of the scattered NO molecules, which probes the kinetic energy uptake or release and hence correlated excitations of NO-O2 pairs. Simultaneous excitations of NO and O2 were resolved for all studied final states of NO. In all cases, the experimental results excellently agree with the results of simulations based on quantum scattering calculations. Trends are discussed by analyzing the scattering wave functions from the calculations.
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Affiliation(s)
- Zhi Gao
- Institute for Molecules and Materials, Radboud University, Heyendaalseweg 135, 6525 AJ Nijmegen, The Netherlands.
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14
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Gao Z, Vogels SN, Besemer M, Karman T, Groenenboom GC, van der Avoird A, van de Meerakker SYT. State-to-State Differential Cross Sections for Inelastic Collisions of NO Radicals with para-H 2 and ortho-D 2. J Phys Chem A 2017; 121:7446-7454. [PMID: 28910536 PMCID: PMC5677768 DOI: 10.1021/acs.jpca.7b06808] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/05/2022]
Abstract
![]()
We
present state-to-state differential cross sections for collisions
of NO molecules (X2Π1/2, j = 1/2f) with para-H2 and ortho-D2 molecules, at a collision
energy of 510 and 450 cm–1, respectively. The angular
scattering distributions for various final states of the NO radical
are measured with high resolution using a crossed molecular beam apparatus
that employs the combination of Stark deceleration and velocity map
imaging. Rotational rainbows as well as diffraction oscillations are
fully resolved in the scattering images. The observed angular scattering
distributions are in excellent agreement with the cross sections obtained
from quantum close-coupling scattering calculations based on recently
computed NO–H2 potential energy surfaces, except
for excitation of NO into the j = 7/2f channel. For
this particular inelastic channel, a significant discrepancy with
theory is observed, despite various additional measurements and calculations,
at present, not understood.
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Affiliation(s)
- Zhi Gao
- Radboud University , Institute for Molecules and Materials, Heyendaalseweg 135, 6525 AJ, Nijmegen, The Netherlands
| | - Sjoerd N Vogels
- Radboud University , Institute for Molecules and Materials, Heyendaalseweg 135, 6525 AJ, Nijmegen, The Netherlands
| | - Matthieu Besemer
- Radboud University , Institute for Molecules and Materials, Heyendaalseweg 135, 6525 AJ, Nijmegen, The Netherlands
| | - Tijs Karman
- Radboud University , Institute for Molecules and Materials, Heyendaalseweg 135, 6525 AJ, Nijmegen, The Netherlands
| | - Gerrit C Groenenboom
- Radboud University , Institute for Molecules and Materials, Heyendaalseweg 135, 6525 AJ, Nijmegen, The Netherlands
| | - Ad van der Avoird
- Radboud University , Institute for Molecules and Materials, Heyendaalseweg 135, 6525 AJ, Nijmegen, The Netherlands
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15
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Luxford TFM, Sharples TR, McKendrick KG, Costen ML. Pair-correlated stereodynamics for diatom-diatom rotational energy transfer: NO(A2Σ+) + N2. J Chem Phys 2017; 147:013912. [DOI: 10.1063/1.4979487] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Thomas F. M. Luxford
- Institute of Chemical Sciences, Heriot-Watt University, Edinburgh EH14 4AS, United Kingdom
| | - Thomas R. Sharples
- Institute of Chemical Sciences, Heriot-Watt University, Edinburgh EH14 4AS, United Kingdom
| | - Kenneth G. McKendrick
- Institute of Chemical Sciences, Heriot-Watt University, Edinburgh EH14 4AS, United Kingdom
| | - Matthew. L. Costen
- Institute of Chemical Sciences, Heriot-Watt University, Edinburgh EH14 4AS, United Kingdom
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16
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Brouard M, Chadwick H, Gordon SDS, Hornung B, Nichols B, Aoiz FJ, Stolte S. Stereodynamics in NO(X) + Ar inelastic collisions. J Chem Phys 2017; 144:224301. [PMID: 27306001 DOI: 10.1063/1.4952649] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The effect of orientation of the NO(X) bond axis prior to rotationally inelastic collisions with Ar has been investigated experimentally and theoretically. A modification to conventional velocity-map imaging ion optics is described, which allows the orientation of hexapole state-selected NO(X) using a static electric field, followed by velocity map imaging of the resonantly ionized scattered products. Bond orientation resolved differential cross sections are measured experimentally for a series of spin-orbit conserving transitions and compared with quantum mechanical calculations. The agreement between experimental results and those from quantum mechanical calculations is generally good. Parity pairs, which have previously been observed in collisions of unpolarized NO with various rare gases, are not observed due to the coherent superposition of the two j = 1/2, Ω = 1/2 Λ-doublet levels in the orienting field. The normalized difference differential cross sections are found to depend predominantly on the final rotational state, and are not very sensitive to the final Λ-doublet level. The differential steric effect has also been investigated theoretically, by means of quantum mechanical and classical calculations. Classically, the differential steric effect can be understood by considering the steric requirement for different types of trajectories that contribute to different regions of the differential cross section. However, classical effects cannot account quantitatively for the differential steric asymmetry observed in NO(X) + Ar collisions, which reflects quantum interference from scattering at either end of the molecule. This quantum interference effect is dominated by the repulsive region of the potential.
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Affiliation(s)
- M Brouard
- The Department of Chemistry, University of Oxford, The Chemistry Research Laboratory, 12 Mansfield Road, Oxford, OX1 3TA, United Kingdom
| | - H Chadwick
- The Department of Chemistry, University of Oxford, The Chemistry Research Laboratory, 12 Mansfield Road, Oxford, OX1 3TA, United Kingdom
| | - S D S Gordon
- The Department of Chemistry, University of Oxford, The Chemistry Research Laboratory, 12 Mansfield Road, Oxford, OX1 3TA, United Kingdom
| | - B Hornung
- The Department of Chemistry, University of Oxford, The Chemistry Research Laboratory, 12 Mansfield Road, Oxford, OX1 3TA, United Kingdom
| | - B Nichols
- The Department of Chemistry, University of Oxford, The Chemistry Research Laboratory, 12 Mansfield Road, Oxford, OX1 3TA, United Kingdom
| | - F J Aoiz
- Departamento de Química Física, Facultad de Química, Universidad Complutense, 28040 Madrid, Spain
| | - S Stolte
- Institute of Atomic and Molecular Physics, Jilin University, Changchun 130012, China
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17
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Brouard M, Gordon SDS, Hackett Boyle A, Heid CG, Nichols B, Walpole V, Aoiz FJ, Stolte S. Integral steric asymmetry in the inelastic scattering of NO(X 2Π). J Chem Phys 2017; 146:014302. [PMID: 28063434 DOI: 10.1063/1.4972565] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The integral steric asymmetry for the inelastic scattering of NO(X) by a variety of collision partners was recorded using a crossed molecular beam apparatus. The initial state of the NO(X, v = 0, j = 1/2, Ω=1/2, ϵ=-1,f) molecule was selected using a hexapole electric field, before the NO bond axis was oriented in a static electric field, allowing probing of the scattering of the collision partner at either the N- or O-end of the molecule. Scattered NO molecules were state selectively probed using (1 + 1') resonantly enhanced multiphoton ionisation, coupled with velocity-map ion imaging. Experimental integral steric asymmetries are presented for NO(X) + Ar, for both spin-orbit manifolds, and Kr, for the spin-orbit conserving manifold. The integral steric asymmetry for spin-orbit conserving and changing transitions of the NO(X) + O2 system is also presented. Close-coupled quantum mechanical scattering calculations employing well-tested ab initio potential energy surfaces were able to reproduce the steric asymmetry observed for the NO-rare gas systems. Quantum mechanical scattering and quasi-classical trajectory calculations were further used to help interpret the integral steric asymmetry for NO + O2. Whilst the main features of the integral steric asymmetry of NO with the rare gases are also observed for the O2 collision partner, some subtle differences provide insight into the form of the underlying potentials for the more complex system.
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Affiliation(s)
- M Brouard
- The Department of Chemistry, The Chemistry Research Laboratory, University of Oxford, 12 Mansfield Road, OX1 3TA Oxford, United Kingdom
| | - S D S Gordon
- The Department of Chemistry, The Chemistry Research Laboratory, University of Oxford, 12 Mansfield Road, OX1 3TA Oxford, United Kingdom
| | - A Hackett Boyle
- The Department of Chemistry, The Chemistry Research Laboratory, University of Oxford, 12 Mansfield Road, OX1 3TA Oxford, United Kingdom
| | - C G Heid
- The Department of Chemistry, The Chemistry Research Laboratory, University of Oxford, 12 Mansfield Road, OX1 3TA Oxford, United Kingdom
| | - B Nichols
- The Department of Chemistry, The Chemistry Research Laboratory, University of Oxford, 12 Mansfield Road, OX1 3TA Oxford, United Kingdom
| | - V Walpole
- The Department of Chemistry, The Chemistry Research Laboratory, University of Oxford, 12 Mansfield Road, OX1 3TA Oxford, United Kingdom
| | - F J Aoiz
- Departamento de Química Física, Facultad de Química, Universidad Complutense, 28040 Madrid, Spain
| | - S Stolte
- The Jilin Institute of Atomic and Molecular Physics, Qianjin Avenue, Changchung 130012, China
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18
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Luxford TFM, Sharples TR, McKendrick KG, Costen ML. Experimental testing of ab initio potential energy surfaces: Stereodynamics of NO(A 2Σ +) + Ne inelastic scattering at multiple collision energies. J Chem Phys 2016; 145:174304. [PMID: 27825214 DOI: 10.1063/1.4966688] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
We present a crossed molecular beam velocity-map ion imaging study of state-to-state rotational energy transfer of NO(A2Σ+, v = 0, N = 0, j = 0.5) in collisions with Ne atoms. From these measurements, we report differential cross sections and angle-resolved rotational angular momentum alignment moments for product states N' = 3 and 5-10 for collisions at an average energy of 523 cm-1, and N' = 3 and 5-14 for collisions at an average energy of 1309 cm-1, respectively. The experimental results are compared to the results of close-coupled quantum scattering calculations on two literature ab initio potential energy surfaces (PESs) [Pajón-Suárez et al., Chem. Phys. Lett. 429, 389 (2006) and Cybulski and Fernández, J. Phys. Chem. A 116, 7319 (2012)]. The differential cross sections from both experiment and theory show clear rotational rainbow structures at both collision energies, and comparison of the angles observed for the rainbow peaks leads to the conclusion that Cybulski and Fernández PES better represents the NO(A2Σ+)-Ne interaction at the collision energies used here. Sharp, forward scattered (<10°), peaks are observed in the experimental differential cross sections for a wide range of N' at both collision energies, which are not reproduced by theory on either PES. We identify these as L-type rainbows, characteristic of attractive interactions, and consistent with a shallow well in the collinear Ne-N-O geometry, similar to that calculated for the NO(A2Σ+)-Ar surface [Kłos et al., J. Chem. Phys. 129, 244303 (2008)], but absent from both of the NO(A2Σ+)-Ne surfaces tested here. The angle-resolved alignment moments calculated by quantum scattering theory are generally in good agreement with the experimental results, but both experiment and quantum scattering theories are dramatically different to the predictions of a classical rigid-shell, kinematic-apse conservation model. Strong oscillations are resolved in the experimental alignment moments as a function of scattering angle, confirming and extending the preliminary report of this behavior [Steill et al., J. Phys. Chem. A 117, 8163 (2013)]. These oscillations are correlated with structure in the differential cross section, suggesting an interference effect is responsible for their appearance.
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Affiliation(s)
- Thomas F M Luxford
- Institute of Chemical Sciences, Heriot-Watt University, Edinburgh EH14 4AS, United Kingdom
| | - Thomas R Sharples
- Institute of Chemical Sciences, Heriot-Watt University, Edinburgh EH14 4AS, United Kingdom
| | - Kenneth G McKendrick
- Institute of Chemical Sciences, Heriot-Watt University, Edinburgh EH14 4AS, United Kingdom
| | - Matthew L Costen
- Institute of Chemical Sciences, Heriot-Watt University, Edinburgh EH14 4AS, United Kingdom
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