1
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Chen XY, Biswas S, Eppelt S, Schindewolf A, Deng F, Shi T, Yi S, Hilker TA, Bloch I, Luo XY. Ultracold field-linked tetratomic molecules. Nature 2024; 626:283-287. [PMID: 38297128 PMCID: PMC10849947 DOI: 10.1038/s41586-023-06986-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2023] [Accepted: 12/15/2023] [Indexed: 02/02/2024]
Abstract
Ultracold polyatomic molecules offer opportunities1 in cold chemistry2,3, precision measurements4 and quantum information processing5,6, because of their rich internal structure. However, their increased complexity compared with diatomic molecules presents a challenge in using conventional cooling techniques. Here we demonstrate an approach to create weakly bound ultracold polyatomic molecules by electroassociation7 (F.D. et al., manuscript in preparation) in a degenerate Fermi gas of microwave-dressed polar molecules through a field-linked resonance8-11. Starting from ground-state NaK molecules, we create around 1.1 × 103 weakly bound tetratomic (NaK)2 molecules, with a phase space density of 0.040(3) at a temperature of 134(3) nK, more than 3,000 times colder than previously realized tetratomic molecules12. We observe a maximum tetramer lifetime of 8(2) ms in free space without a notable change in the presence of an optical dipole trap, indicating that these tetramers are collisionally stable. Moreover, we directly image the dissociated tetramers through microwave-field modulation to probe the anisotropy of their wavefunction in momentum space. Our result demonstrates a universal tool for assembling weakly bound ultracold polyatomic molecules from smaller polar molecules, which is a crucial step towards Bose-Einstein condensation of polyatomic molecules and towards a new crossover from a dipolar Bardeen-Cooper-Schrieffer superfluid13-15 to a Bose-Einstein condensation of tetramers. Moreover, the long-lived field-linked state provides an ideal starting point for deterministic optical transfer to deeply bound tetramer states16-18.
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Affiliation(s)
- Xing-Yan Chen
- Max-Planck-Institut für Quantenoptik, Garching, Germany
- Munich Center for Quantum Science and Technology, Munich, Germany
| | - Shrestha Biswas
- Max-Planck-Institut für Quantenoptik, Garching, Germany
- Munich Center for Quantum Science and Technology, Munich, Germany
| | - Sebastian Eppelt
- Max-Planck-Institut für Quantenoptik, Garching, Germany
- Munich Center for Quantum Science and Technology, Munich, Germany
| | - Andreas Schindewolf
- Max-Planck-Institut für Quantenoptik, Garching, Germany
- Munich Center for Quantum Science and Technology, Munich, Germany
| | - Fulin Deng
- School of Physics and Technology, Wuhan University, Wuhan, China
- CAS Key Laboratory of Theoretical Physics, Institute of Theoretical Physics, Chinese Academy of Sciences, Beijing, China
| | - Tao Shi
- CAS Key Laboratory of Theoretical Physics, Institute of Theoretical Physics, Chinese Academy of Sciences, Beijing, China.
- AS Center for Excellence in Topological Quantum Computation & School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, China.
| | - Su Yi
- CAS Key Laboratory of Theoretical Physics, Institute of Theoretical Physics, Chinese Academy of Sciences, Beijing, China
- AS Center for Excellence in Topological Quantum Computation & School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, China
- Peng Huanwu Collaborative Center for Research and Education, Beihang University, Beijing, China
| | - Timon A Hilker
- Max-Planck-Institut für Quantenoptik, Garching, Germany
- Munich Center for Quantum Science and Technology, Munich, Germany
| | - Immanuel Bloch
- Max-Planck-Institut für Quantenoptik, Garching, Germany
- Munich Center for Quantum Science and Technology, Munich, Germany
- Fakultät für Physik, Ludwig-Maximilians-Universität, Munich, Germany
| | - Xin-Yu Luo
- Max-Planck-Institut für Quantenoptik, Garching, Germany.
- Munich Center for Quantum Science and Technology, Munich, Germany.
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2
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Perera CA, Amarasinghe C, Guo H, Suits AG. Cold collisions of hot molecules. Phys Chem Chem Phys 2023; 25:22595-22606. [PMID: 37602475 DOI: 10.1039/d3cp02071a] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/22/2023]
Abstract
In this Perspective, we review our recent work on rotationally inelastic collisions of highly vibrationally excited NO molecules prepared in single rotational and parity levels at v = 10 using stimulated emission pumping (SEP). This state preparation is employed in a recently developed crossed molecular beam apparatus where two nearly copropagating molecular beams achieve an intersection angle of 4° at the interaction region. This near-copropagating beam geometry of the molecular beams permits very wide tuning of the collision energy, from far above room temperature down to 2 K where we test the theoretical treatment of the attractive part of the potentials and the difference potential for the first time. We have obtained differential cross sections for state-to-state collisions of NO (v = 10) with Ar and Ne in both spin-orbit manifolds using velocity map imaging. Overall good agreement of the experimental results was seen with quantum mechanical close-coupling calculations done on both coupled-cluster and multi-reference configuration interaction potential energy surfaces. Probing cold collisions of NO carrying ∼2 eV of vibrational excitation allows us to test state-of-the-art theory in this extreme nonequilibrium regime.
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Affiliation(s)
- Chatura A Perera
- Department of Chemistry, University of Missouri, Columbia, MO 65211, USA.
| | | | - Hua Guo
- Department of Chemistry and Chemical Biology, University of New Mexico, Albuquerque, New Mexico 87131, USA
| | - Arthur G Suits
- Department of Chemistry, University of Missouri, Columbia, MO 65211, USA.
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3
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Miyamoto Y, Tobaru R, Takahashi Y, Hiramoto A, Iwakuni K, Kuma S, Enomoto K, Baba M. High-resolution spectroscopy of buffer-gas-cooled phthalocyanine. Commun Chem 2022; 5:161. [PMID: 36697667 PMCID: PMC9814875 DOI: 10.1038/s42004-022-00783-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2022] [Accepted: 11/17/2022] [Indexed: 12/02/2022] Open
Abstract
For over five decades, studies in the field of chemical physics and physical chemistry have primarily aimed to understand the quantum properties of molecules. However, high-resolution rovibronic spectroscopy has been limited to relatively small and simple systems because translationally and rotationally cold samples have not been prepared in sufficiently large quantities for large and complex systems. In this study, we present high-resolution rovibronic spectroscopy results for large gas-phase molecules, namely, free-base phthalocya-nine (FBPc). The findings suggest that buffer-gas cooling may be effective for large molecules introduced via laser ablation. High-resolution electronic spectroscopy, combined with other experimental and theoretical studies, will be useful in understanding the quantum properties of molecules. These findings also serve as a guide for quantum chemical calculations of large molecules.
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Affiliation(s)
- Yuki Miyamoto
- grid.261356.50000 0001 1302 4472Research Institute for Interdisciplinary Science, Okayama University, Kita-ku, Okayama Japan
| | - Reo Tobaru
- grid.261356.50000 0001 1302 4472Research Institute for Interdisciplinary Science, Okayama University, Kita-ku, Okayama Japan
| | - Yuiki Takahashi
- grid.20861.3d0000000107068890Division of Physics, Mathematics, and Astronomy, California Institute of Technology, Pasadena, CA USA
| | - Ayami Hiramoto
- grid.261356.50000 0001 1302 4472Research Institute for Interdisciplinary Science, Okayama University, Kita-ku, Okayama Japan
| | - Kana Iwakuni
- grid.266298.10000 0000 9271 9936Institute for Laser Science, University of Electro-Communications, Chofu, Tokyo Japan
| | - Susumu Kuma
- grid.7597.c0000000094465255Atomic, Molecular and Optical Physics Laboratory, RIKEN, Wako, Saitama Japan
| | - Katsunari Enomoto
- grid.267346.20000 0001 2171 836XDepartment of Physics, University of Toyama, Toyama, Japan
| | - Masaaki Baba
- grid.31432.370000 0001 1092 3077Molecular Photoscience Research Center, Kobe University, Nada-ku, Kobe Japan
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4
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Wright SC, Doppelbauer M, Hofsäss S, Christian Schewe H, Sartakov B, Meijer G, Truppe S. Cryogenic buffer gas beams of AlF, CaF, MgF, YbF, Al, Ca, Yb and NO – a comparison. Mol Phys 2022. [DOI: 10.1080/00268976.2022.2146541] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Sidney C. Wright
- Fritz Haber Institute of the Max Planck Society, Berlin, Germany
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5
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Herbers S, Caris YM, Kuijpers SEJ, Grabow JU, van de Meerakker SYT. Efficient transfer of inversion doublet populations in deuterated ammonia using adiabatic rapid passage. Mol Phys 2022. [DOI: 10.1080/00268976.2022.2129105] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/07/2022]
Affiliation(s)
- S. Herbers
- Institute for Molecules and Materials, Radboud Universiteit, Nijmegen, Netherlands
| | - Y. M. Caris
- Institute for Molecules and Materials, Radboud Universiteit, Nijmegen, Netherlands
| | - S. E. J. Kuijpers
- Institute for Molecules and Materials, Radboud Universiteit, Nijmegen, Netherlands
| | - J.-U. Grabow
- Institut für Physikalische Chemie und Elektrochemie, Gottfried Wilhelm Leibniz Universität, Hannover, Germany
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6
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Koller M, Jung F, Phrompao J, Zeppenfeld M, Rabey IM, Rempe G. Electric-Field-Controlled Cold Dipolar Collisions between Trapped CH_{3}F Molecules. PHYSICAL REVIEW LETTERS 2022; 128:203401. [PMID: 35657871 DOI: 10.1103/physrevlett.128.203401] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/01/2022] [Accepted: 04/21/2022] [Indexed: 06/15/2023]
Abstract
Reaching high densities is a key step toward cold-collision experiments with polyatomic molecules. We use a cryofuge to load up to 2×10^{7} CH_{3}F molecules into a boxlike electric trap, achieving densities up to 10^{7}/cm^{3} at temperatures around 350 mK where the elastic dipolar cross section exceeds 7×10^{-12} cm^{2}. We measure inelastic rate constants below 4×10^{-8} cm^{3}/s and control these by tuning a homogeneous electric field that covers a large fraction of the trap volume. Comparison to ab initio calculations gives excellent agreement with dipolar relaxation. Our techniques and findings are generic and immediately relevant for other cold-molecule collision experiments.
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Affiliation(s)
- M Koller
- Max-Planck-Institut für Quantenoptik, Hans-Kopfermann-Strasse 1, 85748 Garching, Germany
| | - F Jung
- Max-Planck-Institut für Quantenoptik, Hans-Kopfermann-Strasse 1, 85748 Garching, Germany
| | - J Phrompao
- Max-Planck-Institut für Quantenoptik, Hans-Kopfermann-Strasse 1, 85748 Garching, Germany
| | - M Zeppenfeld
- Max-Planck-Institut für Quantenoptik, Hans-Kopfermann-Strasse 1, 85748 Garching, Germany
| | - I M Rabey
- Max-Planck-Institut für Quantenoptik, Hans-Kopfermann-Strasse 1, 85748 Garching, Germany
| | - G Rempe
- Max-Planck-Institut für Quantenoptik, Hans-Kopfermann-Strasse 1, 85748 Garching, Germany
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7
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Augenbraun BL, Frenett A, Sawaoka H, Hallas C, Vilas NB, Nasir A, Lasner ZD, Doyle JM. Zeeman-Sisyphus Deceleration of Molecular Beams. PHYSICAL REVIEW LETTERS 2021; 127:263002. [PMID: 35029484 DOI: 10.1103/physrevlett.127.263002] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/07/2021] [Accepted: 11/01/2021] [Indexed: 06/14/2023]
Abstract
We present a robust, continuous molecular decelerator that employs high magnetic fields and few optical pumping steps. CaOH molecules are slowed, accumulating at low velocities in a range sufficient for loading both magnetic and magneto-optical traps. During the slowing, the molecules scatter only seven photons, removing around 8 K of energy. Because large energies can be removed with only a few spontaneous radiative decays, this method can in principle be applied to nearly any paramagnetic atomic or molecular species, opening a general path to trapping of complex molecules.
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Affiliation(s)
- Benjamin L Augenbraun
- Department of Physics, Harvard University, Cambridge, Massachusetts 02138, USA and Harvard-MIT Center for Ultracold Atoms, Cambridge, Massachusetts 02138, USA
| | - Alexander Frenett
- Department of Physics, Harvard University, Cambridge, Massachusetts 02138, USA and Harvard-MIT Center for Ultracold Atoms, Cambridge, Massachusetts 02138, USA
| | - Hiromitsu Sawaoka
- Department of Physics, Harvard University, Cambridge, Massachusetts 02138, USA and Harvard-MIT Center for Ultracold Atoms, Cambridge, Massachusetts 02138, USA
| | - Christian Hallas
- Department of Physics, Harvard University, Cambridge, Massachusetts 02138, USA and Harvard-MIT Center for Ultracold Atoms, Cambridge, Massachusetts 02138, USA
| | - Nathaniel B Vilas
- Department of Physics, Harvard University, Cambridge, Massachusetts 02138, USA and Harvard-MIT Center for Ultracold Atoms, Cambridge, Massachusetts 02138, USA
| | - Abdullah Nasir
- Department of Physics, Harvard University, Cambridge, Massachusetts 02138, USA and Harvard-MIT Center for Ultracold Atoms, Cambridge, Massachusetts 02138, USA
| | - Zack D Lasner
- Department of Physics, Harvard University, Cambridge, Massachusetts 02138, USA and Harvard-MIT Center for Ultracold Atoms, Cambridge, Massachusetts 02138, USA
| | - John M Doyle
- Department of Physics, Harvard University, Cambridge, Massachusetts 02138, USA and Harvard-MIT Center for Ultracold Atoms, Cambridge, Massachusetts 02138, USA
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8
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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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9
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Jurgilas S, Chakraborty A, Rich CJH, Caldwell L, Williams HJ, Fitch NJ, Sauer BE, Frye MD, Hutson JM, Tarbutt MR. Collisions between Ultracold Molecules and Atoms in a Magnetic Trap. PHYSICAL REVIEW LETTERS 2021; 126:153401. [PMID: 33929220 DOI: 10.1103/physrevlett.126.153401] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/05/2021] [Revised: 02/19/2021] [Accepted: 03/04/2021] [Indexed: 06/12/2023]
Abstract
We prepare mixtures of ultracold CaF molecules and Rb atoms in a magnetic trap and study their inelastic collisions. When the atoms are prepared in the spin-stretched state and the molecules in the spin-stretched component of the first rotationally excited state, they collide inelastically with a rate coefficient k_{2}=(6.6±1.5)×10^{-11} cm^{3}/s at temperatures near 100 μK. We attribute this to rotation-changing collisions. When the molecules are in the ground rotational state we see no inelastic loss and set an upper bound on the spin-relaxation rate coefficient of k_{2}<5.8×10^{-12} cm^{3}/s with 95% confidence. We compare these measurements to the results of a single-channel loss model based on quantum defect theory. The comparison suggests a short-range loss parameter close to unity for rotationally excited molecules, but below 0.04 for molecules in the rotational ground state.
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Affiliation(s)
- S Jurgilas
- Centre for Cold Matter, Blackett Laboratory, Imperial College London, Prince Consort Road, London SW7 2AZ, United Kingdom
| | - A Chakraborty
- Centre for Cold Matter, Blackett Laboratory, Imperial College London, Prince Consort Road, London SW7 2AZ, United Kingdom
| | - C J H Rich
- Centre for Cold Matter, Blackett Laboratory, Imperial College London, Prince Consort Road, London SW7 2AZ, United Kingdom
| | - L Caldwell
- Centre for Cold Matter, Blackett Laboratory, Imperial College London, Prince Consort Road, London SW7 2AZ, United Kingdom
| | - H J Williams
- Centre for Cold Matter, Blackett Laboratory, Imperial College London, Prince Consort Road, London SW7 2AZ, United Kingdom
| | - N J Fitch
- Centre for Cold Matter, Blackett Laboratory, Imperial College London, Prince Consort Road, London SW7 2AZ, United Kingdom
| | - B E Sauer
- Centre for Cold Matter, Blackett Laboratory, Imperial College London, Prince Consort Road, London SW7 2AZ, United Kingdom
| | - Matthew D Frye
- Joint Quantum Centre (JQC) Durham-Newcastle, Department of Chemistry, Durham University, South Road, Durham DH1 3LE, United Kingdom
| | - Jeremy M Hutson
- Joint Quantum Centre (JQC) Durham-Newcastle, Department of Chemistry, Durham University, South Road, Durham DH1 3LE, United Kingdom
| | - M R Tarbutt
- Centre for Cold Matter, Blackett Laboratory, Imperial College London, Prince Consort Road, London SW7 2AZ, United Kingdom
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10
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Matsuda K, De Marco L, Li JR, Tobias WG, Valtolina G, Quéméner G, Ye J. Resonant collisional shielding of reactive molecules using electric fields. Science 2021; 370:1324-1327. [PMID: 33303614 DOI: 10.1126/science.abe7370] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2020] [Accepted: 11/09/2020] [Indexed: 11/03/2022]
Abstract
Full control of molecular interactions, including reactive losses, would open new frontiers in quantum science. We demonstrate extreme tunability of ultracold chemical reaction rates by inducing resonant dipolar interactions by means of an external electric field. We prepared fermionic potassium-rubidium molecules in their first excited rotational state and observed a modulation of the chemical reaction rate by three orders of magnitude as we tuned the electric field strength by a few percent across resonance. In a quasi-two-dimensional geometry, we accurately determined the contributions from the three dominant angular momentum projections of the collisions. Using the resonant features, we shielded the molecules from loss and suppressed the reaction rate by an order of magnitude below the background value, thereby realizing a long-lived sample of polar molecules in large electric fields.
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Affiliation(s)
- Kyle Matsuda
- JILA, National Institute of Standards and Technology, and Department of Physics, University of Colorado, Boulder, CO 80309, USA.
| | - Luigi De Marco
- JILA, National Institute of Standards and Technology, and Department of Physics, University of Colorado, Boulder, CO 80309, USA
| | - Jun-Ru Li
- JILA, National Institute of Standards and Technology, and Department of Physics, University of Colorado, Boulder, CO 80309, USA
| | - William G Tobias
- JILA, National Institute of Standards and Technology, and Department of Physics, University of Colorado, Boulder, CO 80309, USA
| | - Giacomo Valtolina
- JILA, National Institute of Standards and Technology, and Department of Physics, University of Colorado, Boulder, CO 80309, USA
| | - Goulven Quéméner
- Université Paris-Saclay, CNRS, Laboratoire Aimé Cotton, 91405 Orsay, France
| | - Jun Ye
- JILA, National Institute of Standards and Technology, and Department of Physics, University of Colorado, Boulder, CO 80309, USA.
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11
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Zou J, Osterwalder A. Investigation of the low-energy stereodynamics in the Ne( 3P 2) + N 2, CO reactions. J Chem Phys 2020; 153:104306. [PMID: 32933296 DOI: 10.1063/5.0022053] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
We report on an experimental investigation of the low-energy stereodynamics of the energy transfer reactions Ne(3P2) + X, producing Ne(1S) + X+ and [Ne-X]+ (X = N2 or CO). Collision energies in the range 0.2 K-700 K are obtained by using the merged beam technique. Two kinds of product ions are generated by Penning and associative ionization, respectively. The intermediate product [Ne-X]+ in vibrationally excited states can predissociate into bare ions (X+). The experimental ratio of the NeX+ and X+ product ion yields is similar for both molecules at high collision energies but diverge at collision energies below 100 K. This difference is explained by the first excited electronic state of the product ions, which is accessible in the case of CO but lies too high in energy in the case of N2.
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Affiliation(s)
- Junwen Zou
- 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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12
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Mitra D, Vilas NB, Hallas C, Anderegg L, Augenbraun BL, Baum L, Miller C, Raval S, Doyle JM. Direct laser cooling of a symmetric top molecule. Science 2020; 369:1366-1369. [DOI: 10.1126/science.abc5357] [Citation(s) in RCA: 64] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2020] [Accepted: 07/10/2020] [Indexed: 11/02/2022]
Abstract
Ultracold polyatomic molecules have potentially wide-ranging applications in quantum simulation and computation, particle physics, and quantum chemistry. For atoms and small molecules, direct laser cooling has proven to be a powerful tool for quantum science in the ultracold regime. However, the feasibility of laser-cooling larger, nonlinear polyatomic molecules has remained unknown because of their complex structure. We laser-cooled the symmetric top molecule calcium monomethoxide (CaOCH3), reducing the temperature of ~104 molecules from 22 ± 1 millikelvin to 1.8 ± 0.7 millikelvin in one dimension and state-selectively cooling two nuclear spin isomers. These results demonstrate that the use of proper ro-vibronic transitions enables laser cooling of nonlinear molecules, thereby opening a path to efficient cooling of chiral molecules and, eventually, optical tweezer arrays of complex polyatomic species.
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Affiliation(s)
- Debayan Mitra
- Department of Physics, Harvard University, Cambridge, MA 02138, USA, and Harvard-MIT Center for Ultracold Atoms, Cambridge, MA 02138, USA
| | - Nathaniel B. Vilas
- Department of Physics, Harvard University, Cambridge, MA 02138, USA, and Harvard-MIT Center for Ultracold Atoms, Cambridge, MA 02138, USA
| | - Christian Hallas
- Department of Physics, Harvard University, Cambridge, MA 02138, USA, and Harvard-MIT Center for Ultracold Atoms, Cambridge, MA 02138, USA
| | - Loïc Anderegg
- Department of Physics, Harvard University, Cambridge, MA 02138, USA, and Harvard-MIT Center for Ultracold Atoms, Cambridge, MA 02138, USA
| | - Benjamin L. Augenbraun
- Department of Physics, Harvard University, Cambridge, MA 02138, USA, and Harvard-MIT Center for Ultracold Atoms, Cambridge, MA 02138, USA
| | - Louis Baum
- Department of Physics, Harvard University, Cambridge, MA 02138, USA, and Harvard-MIT Center for Ultracold Atoms, Cambridge, MA 02138, USA
| | - Calder Miller
- Department of Physics, Harvard University, Cambridge, MA 02138, USA, and Harvard-MIT Center for Ultracold Atoms, Cambridge, MA 02138, USA
| | - Shivam Raval
- Department of Physics, Harvard University, Cambridge, MA 02138, USA, and Harvard-MIT Center for Ultracold Atoms, Cambridge, MA 02138, USA
| | - John M. Doyle
- Department of Physics, Harvard University, Cambridge, MA 02138, USA, and Harvard-MIT Center for Ultracold Atoms, Cambridge, MA 02138, USA
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13
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Baum L, Vilas NB, Hallas C, Augenbraun BL, Raval S, Mitra D, Doyle JM. 1D Magneto-Optical Trap of Polyatomic Molecules. PHYSICAL REVIEW LETTERS 2020; 124:133201. [PMID: 32302203 DOI: 10.1103/physrevlett.124.133201] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/29/2020] [Accepted: 03/09/2020] [Indexed: 06/11/2023]
Abstract
We demonstrate a 1D magneto-optical trap of the polar free radical calcium monohydroxide (CaOH). A quasiclosed cycling transition is established to scatter ∼10^{3} photons per molecule, predominantly limited by interaction time. This enables radiative laser cooling of CaOH while compressing the molecular beam, leading to a significant increase in on axis beam brightness and reduction in temperature from 8.4 to 1.4 mK.
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Affiliation(s)
- Louis Baum
- Harvard-MIT Center for Ultracold Atoms, Cambridge, Massachusetts 02138, USA
- Department of Physics, Harvard University, Cambridge, Massachusetts 02138, USA
| | - Nathaniel B Vilas
- Harvard-MIT Center for Ultracold Atoms, Cambridge, Massachusetts 02138, USA
- Department of Physics, Harvard University, Cambridge, Massachusetts 02138, USA
| | - Christian Hallas
- Harvard-MIT Center for Ultracold Atoms, Cambridge, Massachusetts 02138, USA
- Department of Physics, Harvard University, Cambridge, Massachusetts 02138, USA
| | - Benjamin L Augenbraun
- Harvard-MIT Center for Ultracold Atoms, Cambridge, Massachusetts 02138, USA
- Department of Physics, Harvard University, Cambridge, Massachusetts 02138, USA
| | - Shivam Raval
- Harvard-MIT Center for Ultracold Atoms, Cambridge, Massachusetts 02138, USA
- Department of Physics, Harvard University, Cambridge, Massachusetts 02138, USA
| | - Debayan Mitra
- Harvard-MIT Center for Ultracold Atoms, Cambridge, Massachusetts 02138, USA
- Department of Physics, Harvard University, Cambridge, Massachusetts 02138, USA
| | - John M Doyle
- Harvard-MIT Center for Ultracold Atoms, Cambridge, Massachusetts 02138, USA
- Department of Physics, Harvard University, Cambridge, Massachusetts 02138, USA
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14
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Toscano J, Lewandowski HJ, Heazlewood BR. Cold and controlled chemical reaction dynamics. Phys Chem Chem Phys 2020; 22:9180-9194. [DOI: 10.1039/d0cp00931h] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
State-to-state chemical reaction dynamics, with complete control over the reaction parameters, offers unparalleled insight into fundamental reactivity.
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Affiliation(s)
- Jutta Toscano
- JILA and the Department of Physics
- University of Colorado
- Boulder
- USA
| | | | - Brianna R. Heazlewood
- Physical and Theoretical Chemistry Laboratory (PTCL)
- Department of Chemistry
- University of Oxford
- Oxford
- UK
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15
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Ding S, Wu Y, Finneran IA, Burau JJ, Ye J. Sub-Doppler Cooling and Compressed Trapping of YO Molecules at μK Temperatures. PHYSICAL REVIEW. X 2020; 10:10.1103/physrevx.10.021049. [PMID: 33643688 PMCID: PMC7909871 DOI: 10.1103/physrevx.10.021049] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
Complex molecular structure demands customized solutions to laser cooling by extending its general set of principles and practices. Compared with other laser-cooled molecules, yttrium monoxide (YO) exhibits a large electron-nucleus interaction, resulting in a dominant hyperfine interaction over the electron spin-rotation coupling. The YO ground state is thus comprised of two manifolds of closely spaced states, with one of them possessing a negligible Landé g factor. This unique energy level structure favors dual-frequency dc magneto-optical trapping (MOT) and gray molasses cooling (GMC). We report exceptionally robust cooling of YO at 4 μK over a wide range of laser intensity, detunings (one- and two-photon), and magnetic field. The magnetic insensitivity enables the spatial compression of the molecular cloud by alternating GMC and MOT under the continuous operation of the quadrupole magnetic field. A combination of these techniques produces a laser-cooled molecular sample with the highest phase space density in free space.
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Affiliation(s)
- Shiqian Ding
- JILA, National Institute of Standards and Technology and the University of Colorado, Boulder, Colorado 80309-0440, USA; Department of Physics, University of Colorado, Boulder, Colorado 80309-0390, USA
| | - Yewei Wu
- JILA, National Institute of Standards and Technology and the University of Colorado, Boulder, Colorado 80309-0440, USA; Department of Physics, University of Colorado, Boulder, Colorado 80309-0390, USA
| | - Ian A. Finneran
- JILA, National Institute of Standards and Technology and the University of Colorado, Boulder, Colorado 80309-0440, USA; Department of Physics, University of Colorado, Boulder, Colorado 80309-0390, USA
| | - Justin J. Burau
- JILA, National Institute of Standards and Technology and the University of Colorado, Boulder, Colorado 80309-0440, USA; Department of Physics, University of Colorado, Boulder, Colorado 80309-0390, USA
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Collisions between cold molecules in a superconducting magnetic trap. Nature 2019; 572:189-193. [DOI: 10.1038/s41586-019-1446-2] [Citation(s) in RCA: 44] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2019] [Accepted: 06/12/2019] [Indexed: 11/08/2022]
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Wójcik P, Korona T, Tomza M. Interactions of benzene, naphthalene, and azulene with alkali-metal and alkaline-earth-metal atoms for ultracold studies. J Chem Phys 2019; 150:234106. [PMID: 31228913 DOI: 10.1063/1.5094907] [Citation(s) in RCA: 5] [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 consider collisional properties of polyatomic aromatic hydrocarbon molecules immersed into ultracold atomic gases and investigate intermolecular interactions of exemplary benzene, naphthalene, and azulene with alkali-metal (Li, Na, K, Rb, and Cs) and alkaline-earth-metal (Mg, Ca, Sr, and Ba) atoms. We apply the state-of-the-art ab initio techniques to compute the potential energy surfaces (PESs). We use the coupled cluster method restricted to single, double, and noniterative triple excitations to reproduce the correlation energy and the small-core energy-consistent pseudopotentials to model the scalar relativistic effects in heavier metal atoms. We also report the leading long-range isotropic and anisotropic dispersion and induction interaction coefficients. The PESs are characterized in detail, and the nature of intermolecular interactions is analyzed and benchmarked using symmetry-adapted perturbation theory. The full three-dimensional PESs are provided for the selected systems within the atom-bond pairwise additive representation and can be employed in scattering calculations. The present study of the electronic structure is the first step toward the evaluation of prospects for sympathetic cooling of polyatomic aromatic molecules with ultracold atoms. We suggest azulene, an isomer of naphthalene which possesses a significant permanent electric dipole moment and optical transitions in the visible range, as a promising candidate for electric field manipulation and buffer-gas or sympathetic cooling.
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Affiliation(s)
- Paweł Wójcik
- Faculty of Physics, University of Warsaw, Pasteura 5, 02-093 Warsaw, Poland
| | - Tatiana Korona
- Faculty of Chemistry, University of Warsaw, Pasteura 1, 02-093 Warsaw, Poland
| | - Michał Tomza
- Faculty of Physics, University of Warsaw, Pasteura 5, 02-093 Warsaw, Poland
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18
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Morita M, Tscherbul TV. Restricted basis set coupled-channel calculations on atom-molecule collisions in magnetic fields. J Chem Phys 2019; 150:074110. [PMID: 30795668 DOI: 10.1063/1.5047063] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Rigorous coupled-channel quantum scattering calculations on molecular collisions in external fields are computationally demanding due to the need to account for a large number of coupled channels and multiple total angular momenta J of the collision complex. We show that by restricting the total angular momentum basis to include only the states with helicities K ≤ Kmax, it is possible to obtain accurate elastic and inelastic cross sections for low-temperature He + CaH, Li + CaH, and Li + SrOH collisions in the presence of an external magnetic field at a small fraction of the computational cost of the full coupled-channel calculations (where K is the projection of the molecular rotational angular momentum on the atom-diatom axis). The optimal size of the truncated helicity basis set depends on the mechanism of the inelastic process and on the magnitude of the external magnetic field, with the minimal basis set (Kmax = 0) producing quantitatively accurate results for, e.g., ultracold Li + CaH and Li + SrOH scattering at low magnetic fields, leading to nearly 90-fold gain in computational efficiency. Larger basis sets are required to accurately describe the resonance structure in the magnetic field dependence of Li + CaH and Li + SrOH inelastic cross sections in the few partial wave-regime as well as indirect spin relaxation in He + CaH collisions. Our calculations indicate that the resonance structure is due to an interplay of the spin-rotation and Coriolis couplings between the basis states of different K and the couplings between the rotational states of the same K induced by the anisotropy of the interaction potential.
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Affiliation(s)
- Masato Morita
- Department of Physics, University of Nevada, Reno, Nevada 89557, USA
| | - Timur V Tscherbul
- Department of Physics, University of Nevada, Reno, Nevada 89557, USA
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Collopy AL, Ding S, Wu Y, Finneran IA, Anderegg L, Augenbraun BL, Doyle JM, Ye J. 3D Magneto-Optical Trap of Yttrium Monoxide. PHYSICAL REVIEW LETTERS 2018; 121:213201. [PMID: 30517816 DOI: 10.1103/physrevlett.121.213201] [Citation(s) in RCA: 55] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/02/2018] [Indexed: 06/09/2023]
Abstract
We report three-dimensional trapping of an oxide molecule (YO), using a radio-frequency magneto-optical trap (MOT). The total number of molecules trapped is ∼1.5×10^{4}, with a temperature of 4.1(5) mK. This diversifies the frontier of molecules that are laser coolable and paves the way for the second-stage narrow-line cooling in this molecule to the microkelvin regime. Futhermore, the new challenges of creating a 3D MOT of YO resolved here indicate that MOTs of more complex nonlinear molecules should be feasible as well.
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Affiliation(s)
- Alejandra L Collopy
- JILA, National Institute of Standards and Technology and Department of Physics, University of Colorado, Boulder, Colorado 80309, USA
| | - Shiqian Ding
- JILA, National Institute of Standards and Technology and Department of Physics, University of Colorado, Boulder, Colorado 80309, USA
| | - Yewei Wu
- JILA, National Institute of Standards and Technology and Department of Physics, University of Colorado, Boulder, Colorado 80309, USA
| | - Ian A Finneran
- JILA, National Institute of Standards and Technology and Department of Physics, University of Colorado, Boulder, Colorado 80309, USA
| | - Loïc Anderegg
- Department of Physics and Center for Ultracold Atoms, Harvard University, Cambridge, Massachusetts 02138, USA
| | - Benjamin L Augenbraun
- Department of Physics and Center for Ultracold Atoms, Harvard University, Cambridge, Massachusetts 02138, USA
| | - John M Doyle
- Department of Physics and Center for Ultracold Atoms, Harvard University, Cambridge, Massachusetts 02138, USA
| | - Jun Ye
- JILA, National Institute of Standards and Technology and Department of Physics, University of Colorado, Boulder, Colorado 80309, USA
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Quantum-state-controlled channel branching in cold Ne( 3P 2)+Ar chemi-ionization. Nat Chem 2018; 10:1190-1195. [PMID: 30297754 DOI: 10.1038/s41557-018-0152-2] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2018] [Accepted: 08/31/2018] [Indexed: 11/08/2022]
Abstract
A prerequisite to gain a complete understanding of the most basic aspects of chemical reactions is the ability to perform experiments with complete control over the reactant degrees of freedom. By controlling these, details of a reaction mechanism can be investigated and ultimately manipulated. Here, we present a study of chemi-ionization-a fundamental energy-transfer reaction-under completely controlled conditions. The collision energy of the reagents was tuned from 0.02 K to 1,000 K, with the orientation of the excited Ne atom relative to Ar fully specified by an external magnetic field. Chemi-ionization of Ne(3P2) and Ar in these conditions enables a detailed investigation of how the reaction proceeds, and provides us with a means to control the branching ratio between the two possible reaction outcomes. The merged-beam experimental technique used here allows access to a low-energy regime in which the atoms dynamically reorient into a favourable configuration for reaction, irrespective of their initial orientations.
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Kondov SS, Lee CH, McDonald M, McGuyer BH, Majewska I, Moszynski R, Zelevinsky T. Crossover from the Ultracold to the Quasiclassical Regime in State-Selected Photodissociation. PHYSICAL REVIEW LETTERS 2018; 121:143401. [PMID: 30339457 DOI: 10.1103/physrevlett.121.143401] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/22/2018] [Indexed: 06/08/2023]
Abstract
Processes that break molecular bonds are typically observed with molecules occupying a mixture of quantum states and successfully described with quasiclassical models, while a few studies have explored the distinctly quantum mechanical low-energy regime. Here, we use photodissociation of diatomic strontium molecules to demonstrate the crossover from the ultracold, quantum regime where photofragment angular distributions strongly depend on the kinetic energy to the quasiclassical regime. Using time-of-flight imaging for photodissociation channels with millikelvin reaction barriers, we explore photofragment energies in the 0.1-300 mK range experimentally and up to 3 K theoretically, and discuss the energy scale at which the crossover occurs. We find that the effects of quantum statistics can persist to high photodissociation energies.
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Affiliation(s)
- S S Kondov
- Department of Physics, Columbia University, 538 West 120th Street, New York, New York 10027-5255, USA
| | - C-H Lee
- Department of Physics, Columbia University, 538 West 120th Street, New York, New York 10027-5255, USA
| | - M McDonald
- Department of Physics, Columbia University, 538 West 120th Street, New York, New York 10027-5255, USA
| | - B H McGuyer
- Department of Physics, Columbia University, 538 West 120th Street, New York, New York 10027-5255, USA
| | - I Majewska
- Quantum Chemistry Laboratory, Department of Chemistry, University of Warsaw, Pasteura 1, 02-093 Warsaw, Poland
| | - R Moszynski
- Quantum Chemistry Laboratory, Department of Chemistry, University of Warsaw, Pasteura 1, 02-093 Warsaw, Poland
| | - T Zelevinsky
- Department of Physics, Columbia University, 538 West 120th Street, New York, New York 10027-5255, USA
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22
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Oliveira AN, Sacramento RL, Moreira LS, Azevedo LOA, Wolff W, Lenz Cesar C. Heteronuclear molecules from matrix isolation sublimation and atomic diffusion. J Chem Phys 2018; 149:084201. [DOI: 10.1063/1.5043421] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- A. N. Oliveira
- INMETRO, Av. Nossa Senhora das Graças, 50, 25250-020 Duque de Caxias, RJ, Brazil
- Instituto de Física, Universidade Federal do Rio de Janeiro, Caixa Postal 68528, 21941-972 Rio de Janeiro, RJ, Brazil
| | - R. L. Sacramento
- Instituto de Física, Universidade Federal do Rio de Janeiro, Caixa Postal 68528, 21941-972 Rio de Janeiro, RJ, Brazil
| | - L. S. Moreira
- Instituto de Física, Universidade Federal do Rio de Janeiro, Caixa Postal 68528, 21941-972 Rio de Janeiro, RJ, Brazil
| | - L. O. A. Azevedo
- Instituto de Física, Universidade Federal do Rio de Janeiro, Caixa Postal 68528, 21941-972 Rio de Janeiro, RJ, Brazil
| | - W. Wolff
- Instituto de Física, Universidade Federal do Rio de Janeiro, Caixa Postal 68528, 21941-972 Rio de Janeiro, RJ, Brazil
| | - C. Lenz Cesar
- Instituto de Física, Universidade Federal do Rio de Janeiro, Caixa Postal 68528, 21941-972 Rio de Janeiro, RJ, Brazil
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