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von Jeinsen NA, Lambrick SM, Bergin M, Radić A, Liu B, Seremet D, Jardine AP, Ward DJ. 2D Helium Atom Diffraction from a Microscopic Spot. PHYSICAL REVIEW LETTERS 2023; 131:236202. [PMID: 38134765 DOI: 10.1103/physrevlett.131.236202] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/03/2023] [Revised: 06/01/2023] [Accepted: 09/20/2023] [Indexed: 12/24/2023]
Abstract
A method for measuring helium atom diffraction with micron-scale spatial resolution is demonstrated in a scanning helium microscope (SHeM) and applied to study a micron-scale spot on the (100) plane of a lithium fluoride (LiF) crystal. The positions of the observed diffraction peaks provide an accurate measurement of the local lattice spacing, while a combination of close-coupled scattering calculations and Monte Carlo ray-tracing simulations reproduce the main variations in diffracted intensity. Subsequently, the diffraction results are used to enhance image contrast by measuring at different points in reciprocal space. The results open up the possibility for using helium microdiffraction to characterize the morphology of delicate or electron-sensitive materials on small scales. These include many fundamentally and technologically important samples which cannot be studied in conventional atom scattering instruments, such as small grain size exfoliated 2D materials, polycrystalline samples, and other surfaces that do not exhibit long-range order.
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Affiliation(s)
- Nick A von Jeinsen
- Department of Physics, Cavendish Laboratory, JJ Thomson Avenue, University of Cambridge, Cambridge CB3 0HE, United Kingdom
| | - Sam M Lambrick
- Department of Physics, Cavendish Laboratory, JJ Thomson Avenue, University of Cambridge, Cambridge CB3 0HE, United Kingdom
| | - Matthew Bergin
- Centre for Organic Electronics, Physics Building, University of Newcastle, Callaghan, New South Wales 2308, Australia
| | - Aleksandar Radić
- Department of Physics, Cavendish Laboratory, JJ Thomson Avenue, University of Cambridge, Cambridge CB3 0HE, United Kingdom
| | - Boyao Liu
- Department of Physics, Cavendish Laboratory, JJ Thomson Avenue, University of Cambridge, Cambridge CB3 0HE, United Kingdom
| | - Dan Seremet
- Department of Physics, Cavendish Laboratory, JJ Thomson Avenue, University of Cambridge, Cambridge CB3 0HE, United Kingdom
| | - Andrew P Jardine
- Department of Physics, Cavendish Laboratory, JJ Thomson Avenue, University of Cambridge, Cambridge CB3 0HE, United Kingdom
| | - David J Ward
- Department of Physics, Cavendish Laboratory, JJ Thomson Avenue, University of Cambridge, Cambridge CB3 0HE, United Kingdom
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Allison W, Miret-Artés S, Pollak E. Reply to the 'Comment on "Perturbation theory of scattering for grazing-incidence fast-atom diffraction"' by G. A. Bocan, H. Breiss, S. Szilasi, A. Momeni, E. M. S. Casagrande, E. A. Sánchez, M. S. Gravielle and H. Khemliche, Phys. Chem. Chem. Phys., 2023, 25, DOI: 10.1039/D3CP02486E. Phys Chem Chem Phys 2023. [PMID: 38047621 DOI: 10.1039/d3cp04559e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/05/2023]
Abstract
In this Reply, we show that criticisms of perturbation theory for grazing-incidence fast-atom diffraction (GIFAD) are ill-founded. We show explicitly that our formulation (W. Allison, S. Miret-Artés and E. Pollak, Phys. Chem. Chem. Phys., 2022, 24, 15851) provides a similar precision in describing the observed phenomena as ab initio potentials. Since that is the main criterion to distinguish between methods, it seems reasonable to conclude that the perturbation approach using a Morse-type potential reproduces the essential aspects of the dynamics correctly. In addition we expand on the historical context and summarize the physical insights provided by our methods.
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Affiliation(s)
- W Allison
- SMF Cavendish Laboratory, JJ Thomson Avenue, Cambridge, UK.
| | - S Miret-Artés
- Instituto de Física Fundamental, Consejo Superior de Investigaciones Científicas, Serrano 123, Madrid 28006, Spain.
| | - E Pollak
- Chemical and Biological Physics Department, Weizmann Institute of Science, Rehovoth 76100, Israel.
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Bocan GA, Breiss H, Szilasi S, Momeni A, Staicu Casagrande EM, Sánchez EA, Gravielle MS, Khemliche H. Comment on "Perturbation theory of scattering for grazing-incidence fast-atom diffraction", by W. Allison, S. Miret-Artés and E. Pollak, Phys. Chem. Chem. Phys., 2022, 24, 15851. Phys Chem Chem Phys 2023. [PMID: 38047619 DOI: 10.1039/d3cp02486e] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/05/2023]
Abstract
In this comment we discuss some aspects of Phys. Chem. Chem. Phys., 2022, 24, 15851, by Allison et al., an article intensely motivated by our study of grazing incidence fast atom diffraction (GIFAD) for He-KCl(001) [G. A. Bocan, H. Breiss, S. Szilasi, A. Momeni, M. E. Staicu Casagrande, M. S. Gravielle, E. A. Sánchez and H. Khemliche, Phys. Rev. Lett., 2020, 125, 096101; G. A. Bocan, H. Breiss, S. Szilasi, A. Momeni, M. E. Staicu Casagrande, E. A. Sánchez, M. S. Gravielle and H. Khemliche, Phys. Rev. B, 2021, 104, 235401]. In particular, (a) we show that, contrary to first order perturbation prediction, the surface corrugation is not proportional to the tangent of the rainbow angle and, (b) we analyze whether a Morse-like formula, like the one Allison et al. use, is able to reproduce the atom-surface potential derived from density functional theory (DFT) calculations. In addition, we give some clarifications regarding specific remarks the authors made about our articles.
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Affiliation(s)
- Gisela Anahí Bocan
- Instituto de Nanociencia y Nanotecnología - Nodo Bariloche (CNEA-CONICET), Centro Atómico Bariloche, Av. Bustillo 9500, S.C. de Bariloche 8400, Argentina.
| | - Hanadi Breiss
- Université Paris-Saclay, CNRS, Institut des Sciences Moléculaires d'Orsay, 91405, Orsay, France
| | - Samir Szilasi
- Université Paris-Saclay, CNRS, Institut des Sciences Moléculaires d'Orsay, 91405, Orsay, France
| | - Anouchah Momeni
- Université Paris-Saclay, CNRS, Institut des Sciences Moléculaires d'Orsay, 91405, Orsay, France
- CY Cergy Paris Université, Cergy F-95000, France
| | | | - Esteban Alejandro Sánchez
- Instituto de Nanociencia y Nanotecnología - Nodo Bariloche (CNEA-CONICET), Centro Atómico Bariloche, Av. Bustillo 9500, S.C. de Bariloche 8400, Argentina.
- Instituto Balseiro (U. N. Cuyo), Centro Atómico Bariloche, Av. Bustillo 9500, S.C. de Bariloche 8400, Argentina
| | - María Silvia Gravielle
- Instituto de Astronomía y Física del Espacio (UBA-CONICET), Buenos Aires C1428EGA, Argentina.
| | - Hocine Khemliche
- Université Paris-Saclay, CNRS, Institut des Sciences Moléculaires d'Orsay, 91405, Orsay, France
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Pan P, Rad JN, Roncin P. A setup for grazing incidence fast atom diffraction. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2022; 93:093305. [PMID: 36182520 DOI: 10.1063/5.0099269] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/16/2022] [Accepted: 08/05/2022] [Indexed: 06/16/2023]
Abstract
We describe a UHV setup for grazing incidence fast atom diffraction (GIFAD) experiments. The overall geometry is simply a source of keV atoms facing an imaging detector. Therefore, it is very similar to the geometry of reflection high energy electron diffraction experiments used to monitor growth at surfaces. Several custom instrumental developments are described making GIFAD operation efficient and straightforward. The difficulties associated with accurately measuring the small scattering angle and the related calibration are carefully analyzed.
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Affiliation(s)
- Peng Pan
- Université Paris-Saclay, CNRS, Institut des Sciences Moléculaires d'Orsay (ISMO), 91405 Orsay, France
| | - Jaafar Najafi Rad
- Université Paris-Saclay, CNRS, Institut des Sciences Moléculaires d'Orsay (ISMO), 91405 Orsay, France
| | - Philippe Roncin
- Université Paris-Saclay, CNRS, Institut des Sciences Moléculaires d'Orsay (ISMO), 91405 Orsay, France
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Del Cueto M, Muzas AS, Martín F, Díaz C. Stereodynamics effects in grazing-incidence fast-molecule diffraction. Phys Chem Chem Phys 2022; 24:19541-19551. [PMID: 35938887 DOI: 10.1039/d2cp02109a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Grazing-incidence fast-projectile diffraction has been proposed both as a complement and an alternative to thermal-energy projectile scattering, which explains the interest that this technique has received in recent years, especially in the case of atomic projectiles. On the other hand, despite the richer physics involved, molecular projectiles have received much less attention. In this work, we present a theoretical study of grazing-incidence fast-molecule diffraction of H2 from KCl(001) using a six-dimensional density functional theory based potential energy surface and a time-dependent wavepacket propagation method. The analysis of the computed diffraction patterns as a function of the molecular alignment, and their comparison with the available experimental data, where the initial distribution of rotational states in the molecule is not known, reveals a puzzling stereodynamics effect of the diffracted projectiles: diffracted molecules aligned perpendicular, or quasi perpendicular, to the surface reproduce rather well the experimental diffraction pattern, whereas those molecules aligned parallel to or tilted with respect to the surface do not behave as in the experiments. These results call for more detailed investigations of the molecular beam generation process.
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Affiliation(s)
- M Del Cueto
- Department of Chemistry, University of Liverpool, Liverpool, L69 3BK, UK
| | - A S Muzas
- Centro de Física de Materiales CFM/MPC (CSIC-UPV/EHU), 20018 Donotia-San Sebastián, Spain
| | - F Martín
- Departamento de Química Módulo 13, Universidad Autónoma de Madrid, 28049 Madrid, Spain.,Condensed Matter Physics Center (IFIMAC), Universidad Autónoma de Madrid, 28049 Madrid, Spain.,Instituto Madrileño de Estudios Avanzado en Nanociencia (IMDEA-Nanociencia), Cantoblanco 28049, Madrid, Spain
| | - C Díaz
- Departamento de Química Física, Facultad de CC. Químicas, Universidad Complutense de Madrid, 28040 Madrid, Spain.
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Manson JR, Miret-Artés S. Atom-surface scattering in the classical multiphonon regime. Phys Chem Chem Phys 2022; 24:16942-16972. [PMID: 35796229 DOI: 10.1039/d2cp01144a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Many experiments that utilize beams of incident atoms colliding with surfaces as a probe of surface properties are carried out at large energies, high temperatures and with large mass atoms. Under these conditions the scattering process does not exhibit quantum mechanical properties such as diffraction or single-phonon excitation, but rather can be treated with classical physics. This is a review of work carried out by the authors over a span of several years to develop theoretical frameworks using classical physics for describing the scattering interactions of atom with surfaces.
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Affiliation(s)
- J R Manson
- Donostia International Physics Center (DIPC), Paseo Manuel de Lardizabal, 4, 20018 Donostia-San Sebastian, Spain.,Department of Physics and Astronomy, Clemson University, Clemson, South Carolina 29634, USA
| | - S Miret-Artés
- Donostia International Physics Center (DIPC), Paseo Manuel de Lardizabal, 4, 20018 Donostia-San Sebastian, Spain.,Instituto de Física Fundamental, Consejo Superior de Investigaciones Científicas, Serrano 123, 28006 Madrid, Spain.
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Allison W, Miret-Artés S, Pollak E. Perturbation theory of scattering for grazing-incidence fast-atom diffraction. Phys Chem Chem Phys 2022; 24:15851-15859. [PMID: 35748328 DOI: 10.1039/d2cp01013e] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Recent grazing-incidence, fast atom diffraction (GIFAD) experiments have highlighted the well known observation that the distance between classical rainbow angles depends on the incident energy. The GIFAD experiments imply an incident vertical scattering angle, facilitating an analytic analysis using classical perturbation theory, which leads to the conclusion that the so called "dynamic corrugation" amplitude, as defined by Bocan et al., Phys. Rev. Lett., 2020 125, 096101 is, within first-order perturbation theory, proportional to the tangent of the rainbow angle. Therefore it provides no further information about the interaction than is gleaned from the rainbow angle and its energy dependence. Perhaps more importantly, the resulting analytic theory reveals how the energy dependence of rainbow angles may be inverted into information on the force field governing the interaction of the incident projectile with the surface.
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Affiliation(s)
| | - Salvador Miret-Artés
- Spanish Scientific Research Council, Institute of Fundamental Physics, Department of Atomic, Molecular and Surface Processes, Serrano 123, Madrid 28006, Spain.
| | - Eli Pollak
- Chemical and Biological Physics Department, Weizmann Insitute of Science, 76100 Rehovoth, Israel.
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Díaz C, Gravielle MS. Grazing incidence fast atom and molecule diffraction: theoretical challenges. Phys Chem Chem Phys 2022; 24:15628-15656. [PMID: 35730987 DOI: 10.1039/d2cp01246d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
This perspective article reviews the state-of-the-art of grazing incidence fast atom and molecule diffraction (GIFAD and GIFMD) simulations and addresses the main challenges that theorists, aiming to provide useful inputs in this topic, are facing. We first discuss briefly the methods used to build accurate potential energy surfaces describing the interaction between the projectile and the surface. Subsequently, we focus on the dynamics simulation methods for GIFAD, a phenomenon that has received a lot of experimental attention since 2007, when the first measurements were published. Following this experimental effort, theorists have developed and adapted a bunch of methods able to simulate, analyze and extract information from the experimental outputs. We review these methods, from the very simple ones based on classical dynamics to the full quantum ones, paying special attention to more versatile semiclassical approaches, which include quantum ingredients in the dynamics at a computational cost only slightly higher than that required in classical dynamics. Within the semiclassical framework it is possible, for example, to include in the dynamics the surface phonons and the projectile coherence, two factors that may have a relevant influence on the experimental measurements, at a reasonable computational cost. Finally, we address GIFMD, a phenomenon that has received much less attention and for which there is still a lot of room for research. We review the few examples of GIFMD available in the literature, and we discuss new phenomena associated with the molecular internal degrees of freedom, which may have some impact in other closely related fields, such as molecular reactivity on metal surfaces. Finally, we point out opened questions, raised from the comparisons between theoretical and experimental results, which claim for further experimental efforts.
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Affiliation(s)
- Cristina Díaz
- Departamento de Química Física, Facultad de CC. Químicas, Universidad Complutense de Madrid, 28040 Madrid, Spain.
| | - María Silvia Gravielle
- Instituto de Astronomía y Física del Espacio (IAFE, UBA-CONICET), Ciudad Universitaria, C1428EGA, Buenos Aires, Argentina.
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Schmutzler SJ, Ruckhofer A, Ernst WE, Tamtögl A. Surface electronic corrugation of a one-dimensional topological metal: Bi(114). Phys Chem Chem Phys 2022; 24:9146-9155. [PMID: 35191440 PMCID: PMC9020329 DOI: 10.1039/d1cp05284e] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2021] [Accepted: 02/09/2022] [Indexed: 12/03/2022]
Abstract
The surface of Bi(114) is a striking example where the reduced dimensionality gives rise to structural rearrangement and new states at the surface. Here, we present a study of the surface structure and electronic corrugation of this quasi one-dimensional topological metal based on helium atom scattering (HAS) measurements. In contrast to low-index metal surfaces, upon scattering from the stepped (114) truncation of Bi, a large proportion of the incident beam is scattered into higher order diffraction channels which in combination with the large surface unit cell makes an analysis challenging. The surface electronic corrugation of Bi(114) is determined, using measurements upon scattering normal to the steps, together with quantum mechanical scattering calculations. Therefore, minimisation routines that vary the shape of the corrugation are employed, in order to minimise the deviation between the calculations and experimental scans. Furthermore, we illustrate that quantum mechanical scattering calculations can be used to determine the orientation of the in- and outgoing beam with respect to the stepped surface structure.
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Affiliation(s)
- Stephan J Schmutzler
- Institute of Experimental Physics, Graz University of Technology, 8010 Graz, Austria.
- Freie Universität Berlin, Fachbereich Physik, Arnimallee 14, 14195 Berlin, Germany
| | - Adrian Ruckhofer
- Institute of Experimental Physics, Graz University of Technology, 8010 Graz, Austria.
| | - Wolfgang E Ernst
- Institute of Experimental Physics, Graz University of Technology, 8010 Graz, Austria.
| | - Anton Tamtögl
- Institute of Experimental Physics, Graz University of Technology, 8010 Graz, Austria.
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