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Pang R, Yin J, Wang Y, Lin Q, Wang Z, Xu L, Hou S, Wang H, Yin J, Yang T. Theoretical Investigation of Spectroscopic Properties of the Alkaline-Earth-Metal Monohydrides toward Laser Cooling and Magneto-Optical Trapping. ACS OMEGA 2023; 8:19391-19401. [PMID: 37305276 PMCID: PMC10249082 DOI: 10.1021/acsomega.3c00352] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/17/2023] [Accepted: 04/10/2023] [Indexed: 06/13/2023]
Abstract
Alkaline-earth-metal monohydrides MH (M = Be, Mg, Ca, Sr, Ba) have long been regarded as promising candidates toward laser cooling and trapping; however, their rich internal level structures that are amenable to magneto-optical trapping have not been completely explored. Here, we first systematically evaluated Franck-Condon factors of these alkaline-earth-metal monohydrides in the A2Π1/2 ← X2Σ+ transition, exploiting three respective methods (the Morse potential, the closed-form approximation, and the Rydberg-Klein-Rees method). The effective Hamiltonian matrix was introduced for MgH, CaH, SrH, and BaH individually in order to figure out their molecular hyperfine structures of X2Σ+, the transition wavelengths in the vacuum, and hyperfine branching ratios of A2Π1/2(J' = 1/2,+) ← X2Σ+(N = 1,-), followed by possible sideband modulation proposals to address all hyperfine manifolds. Lastly, the Zeeman energy level structures and associated magnetic g factors of the ground state X2Σ+(N = 1,-) were also presented. Our theoretical results here not only shed more light on the molecular spectroscopy of alkaline-earth-metal monohydrides toward laser cooling and magneto-optical trapping but also can contribute to research in molecular collisions involving few-atom molecular systems, spectral analysis in astrophysics and astrochemistry, and even precision measurement of fundamental constants such as the quest for nonzero detection of electron's electric dipole moment.
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Affiliation(s)
- Renjun Pang
- State
Key Laboratory of Precision Spectroscopy, East China Normal University, Shanghai 200062, P. R. China
| | - Junhao Yin
- State
Key Laboratory of Precision Spectroscopy, East China Normal University, Shanghai 200062, P. R. China
| | - Yueyang Wang
- State
Key Laboratory of Precision Spectroscopy, East China Normal University, Shanghai 200062, P. R. China
| | - Qinning Lin
- State
Key Laboratory of Precision Spectroscopy, East China Normal University, Shanghai 200062, P. R. China
| | - Zesen Wang
- State
Key Laboratory of Precision Spectroscopy, East China Normal University, Shanghai 200062, P. R. China
| | - Liang Xu
- Shanghai
Key Laboratory of Modern Optical Systems, University of Shanghai for Science and Technology, Shanghai 200093, P. R. China
| | - Shunyong Hou
- State
Key Laboratory of Precision Spectroscopy, East China Normal University, Shanghai 200062, P. R. China
| | - Hailing Wang
- State
Key Laboratory of Precision Spectroscopy, East China Normal University, Shanghai 200062, P. R. China
| | - Jianping Yin
- State
Key Laboratory of Precision Spectroscopy, East China Normal University, Shanghai 200062, P. R. China
| | - Tao Yang
- State
Key Laboratory of Precision Spectroscopy, East China Normal University, Shanghai 200062, P. R. China
- Collaborative
Innovation Center of Extreme Optics, Shanxi
University, Taiyuan, Shanxi 030006, P.
R. China
- Xinjiang
Astronomical Observatory, Chinese Academy
of Sciences, 150 Science
1-Street, Urumqi, Xinjiang 830011, P. R. China
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2
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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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3
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Koyu S, Hermsmeier R, Tscherbul TV. Total angular momentum representation for state-to-state quantum scattering of cold molecules in a magnetic field. J Chem Phys 2022; 156:034112. [DOI: 10.1063/5.0074844] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Suyesh Koyu
- Department of Physics, University of Nevada, Reno, Nevada 89557, USA
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4
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Bhandari A, Rollings AP, Ratto L, Weinstein JD. High-purity solid parahydrogen. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2021; 92:073202. [PMID: 34340409 DOI: 10.1063/5.0049006] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/28/2021] [Accepted: 06/11/2021] [Indexed: 06/13/2023]
Abstract
Alkali atoms trapped in solid hydrogen matrices have demonstrated ultralong electron spin coherence times and are promising as quantum sensors. Their spin coherence is limited by magnetic noise from naturally occurring orthohydrogen molecules in the parahydrogen matrix. In the gas phase, the orthohydrogen component of hydrogen can be converted to parahydrogen by flowing it over a catalyst held at cryogenic temperatures, with lower temperatures giving a lower orthohydrogen fraction. In this work, we use a single cryostat to reduce the orthohydrogen fraction of hydrogen gas and grow a solid matrix from the resulting high-purity parahydrogen. We demonstrate the operation of the catalyst down to a temperature of 8 K, and we spectroscopically verify that orthohydrogen impurities in the resulting solid are at a level <10-6. We also find that, at sufficiently low temperatures, the cryogenic catalyst provides isotopic purification, reducing the HD fraction.
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Affiliation(s)
- Ashok Bhandari
- Department of Physics, University of Nevada, Reno, Nevada 89557, USA
| | | | - Levi Ratto
- Department of Physics, University of Nevada, Reno, Nevada 89557, USA
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5
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Abstract
The prospect of cooling matter down to temperatures that are close to absolute zero raises intriguing questions about how chemical reactivity changes under these extreme conditions. Although some types of chemical reaction still occur at 1 μK, they can no longer adhere to the conventional picture of reactants passing over an activation energy barrier to become products. Indeed, at ultracold temperatures, the system enters a fully quantum regime, and quantum mechanics replaces the classical picture of colliding particles. In this Review, we discuss recent experimental and theoretical developments that allow us to explore chemical reactions at temperatures that range from 100 K to 500 nK. Although the field is still in its infancy, exceptional control has already been demonstrated over reactivity at low temperatures.
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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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7
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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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8
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Xu S, Xia M, Yin Y, Gu R, Xia Y, Yin J. Determination of the normal A 2Π state in MgF with application to direct laser cooling of molecules. J Chem Phys 2019; 150:084302. [PMID: 30823751 DOI: 10.1063/1.5083898] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
We report high resolution electronic spectroscopy of cold magnesium monofluoride (MgF) molecules in the gas phase, which are created by a combination of laser ablation, chemical reaction, and 6 K helium buffer-gas cooling. Thanks to the sufficient population in the low-lying rotational states, the P, Q, and R branches in the electronic transition of the X2Σ+ to A2Π state are able to be measured unambiguously by in-cell absorption spectra. For the first time, we show that the A2Π state of MgF is actually a normal state, not an inverted one. The laser cooling relevant transitions X2Σ+v=0,1,N=1→A2Π1/2(v=0,J'=1/2) are also identified, along with the hyperfine structure of the X2Σ+(v = 0, N = 1) state. This study provides an important step for ongoing laser cooling experiments of MgF molecules.
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Affiliation(s)
- Supeng Xu
- State Key Laboratory of Precision Spectroscopy, Department of Physics, East China Normal University, Shanghai 200062, China
| | - Meng Xia
- State Key Laboratory of Precision Spectroscopy, Department of Physics, East China Normal University, Shanghai 200062, China
| | - Yanning Yin
- State Key Laboratory of Precision Spectroscopy, Department of Physics, East China Normal University, Shanghai 200062, China
| | - Ruoxi Gu
- State Key Laboratory of Precision Spectroscopy, Department of Physics, East China Normal University, Shanghai 200062, China
| | - Yong Xia
- State Key Laboratory of Precision Spectroscopy, Department of Physics, East China Normal University, Shanghai 200062, China
| | - Jianping Yin
- State Key Laboratory of Precision Spectroscopy, Department of Physics, East China Normal University, Shanghai 200062, China
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9
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Tennyson J, McKemmish LK, Rivlin T. Low-temperature chemistry using the R-matrix method. Faraday Discuss 2018; 195:31-48. [PMID: 27711838 DOI: 10.1039/c6fd00110f] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Techniques for producing cold and ultracold molecules are enabling the study of chemical reactions and scattering at the quantum scattering limit, with only a few partial waves contributing to the incident channel, leading to the observation and even full control of state-to-state collisions in this regime. A new R-matrix formalism is presented for tackling problems involving low- and ultra-low energy collisions. This general formalism is particularly appropriate for slow collisions occurring on potential energy surfaces with deep wells. The many resonance states make such systems hard to treat theoretically but offer the best prospects for novel physics: resonances are already being widely used to control diatomic systems and should provide the route to steering ultracold reactions. Our R-matrix-based formalism builds on the progress made in variational calculations of molecular spectra by using these methods to provide wavefunctions for the whole system at short internuclear distances, (a regime known as the inner region). These wavefunctions are used to construct collision energy-dependent R-matrices which can then be propagated to give cross sections at each collision energy. The method is formulated for ultracold collision systems with differing numbers of atoms.
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Affiliation(s)
- Jonathan Tennyson
- Department of Physics and Astronomy, University College London, London WC1E 6BT, UK.
| | - Laura K McKemmish
- Department of Physics and Astronomy, University College London, London WC1E 6BT, UK.
| | - Tom Rivlin
- Department of Physics and Astronomy, University College London, London WC1E 6BT, UK.
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10
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Bohn JL, Rey AM, Ye J. Cold molecules: Progress in quantum engineering of chemistry and quantum matter. Science 2017; 357:1002-1010. [PMID: 28883071 DOI: 10.1126/science.aam6299] [Citation(s) in RCA: 135] [Impact Index Per Article: 19.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Cooling atoms to ultralow temperatures has produced a wealth of opportunities in fundamental physics, precision metrology, and quantum science. The more recent application of sophisticated cooling techniques to molecules, which has been more challenging to implement owing to the complexity of molecular structures, has now opened the door to the longstanding goal of precisely controlling molecular internal and external degrees of freedom and the resulting interaction processes. This line of research can leverage fundamental insights into how molecules interact and evolve to enable the control of reaction chemistry and the design and realization of a range of advanced quantum materials.
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Affiliation(s)
- John L Bohn
- JILA, National Institute of Standards and Technology and University of Colorado Boulder, Boulder, CO 80309-0440, USA.
| | - Ana Maria Rey
- JILA, National Institute of Standards and Technology and University of Colorado Boulder, Boulder, CO 80309-0440, USA.
| | - Jun Ye
- JILA, National Institute of Standards and Technology and University of Colorado Boulder, Boulder, CO 80309-0440, USA.
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11
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Quiros N, Tariq N, Tscherbul TV, Kłos J, Weinstein JD. Cold Anisotropically Interacting van der Waals Molecule: TiHe. PHYSICAL REVIEW LETTERS 2017; 118:213401. [PMID: 28598640 DOI: 10.1103/physrevlett.118.213401] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/21/2017] [Indexed: 06/07/2023]
Abstract
We have used laser ablation and helium buffer-gas cooling to produce titanium-helium van der Waals molecules at cryogenic temperatures. The molecules were detected through laser-induced fluorescence spectroscopy. Ground-state Ti(a^{3}F_{2})-He binding energies were determined for the ground and first rotationally excited states from studying equilibrium thermodynamic properties, and found to agree well with theoretical calculations based on newly calculated ab initio Ti-He interaction potentials, opening up novel possibilities for studying the formation, dynamics, and nonuniversal chemistry of van der Waals clusters at low temperatures.
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Affiliation(s)
- Nancy Quiros
- Department of Physics, University of Nevada, Reno, Nevada 89557, USA
| | - Naima Tariq
- Department of Physics, University of Nevada, Reno, Nevada 89557, USA
| | - Timur V Tscherbul
- Department of Physics, University of Nevada, Reno, Nevada 89557, USA
| | - Jacek Kłos
- Department of Chemistry and Biochemistry, University of Maryland, College Park, Maryland 20742, USA
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12
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Balakrishnan N. Perspective: Ultracold molecules and the dawn of cold controlled chemistry. J Chem Phys 2016; 145:150901. [DOI: 10.1063/1.4964096] [Citation(s) in RCA: 157] [Impact Index Per Article: 19.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- N. Balakrishnan
- Department of Chemistry, University of Nevada, Las Vegas, Nevada 89154, USA
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13
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Piskorski J, Patterson D, Eibenberger S, Doyle JM. Cooling, Spectroscopy and Non-Sticking oftrans-Stilbene and Nile Red. Chemphyschem 2014; 15:3800-4. [DOI: 10.1002/cphc.201402502] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2014] [Indexed: 11/11/2022]
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14
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Lu HI, Kozyryev I, Hemmerling B, Piskorski J, Doyle JM. Magnetic trapping of molecules via optical loading and magnetic slowing. PHYSICAL REVIEW LETTERS 2014; 112:113006. [PMID: 24702363 DOI: 10.1103/physrevlett.112.113006] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/09/2013] [Indexed: 06/03/2023]
Abstract
Calcium monofluoride (CaF) is magnetically slowed and trapped using optical pumping. Starting from a collisionally cooled slow beam, CaF with an initial velocity of ∼ 30 m/s is slowed via magnetic forces as it enters a 800 mK deep magnetic trap. Employing two-stage optical pumping, CaF is irreversibly loaded into the trap via two scattered photons. We observe a trap lifetime exceeding 500 ms limited by background collisions. This method paves the way for cooling and magnetic trapping of chemically diverse molecules without closed cycling transitions.
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Affiliation(s)
- Hsin-I Lu
- School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138, USA and Harvard-MIT Center for Ultracold Atoms, Cambridge, Massachusetts 02138, USA
| | - Ivan Kozyryev
- Harvard-MIT Center for Ultracold Atoms, Cambridge, Massachusetts 02138, USA and Department of Physics, Harvard University, Cambridge, Massachusetts 02138, USA
| | - Boerge Hemmerling
- Harvard-MIT Center for Ultracold Atoms, Cambridge, Massachusetts 02138, USA and Department of Physics, Harvard University, Cambridge, Massachusetts 02138, USA
| | - Julia Piskorski
- Harvard-MIT Center for Ultracold Atoms, Cambridge, Massachusetts 02138, USA and Department of Physics, Harvard University, Cambridge, Massachusetts 02138, USA
| | - John M Doyle
- Harvard-MIT Center for Ultracold Atoms, Cambridge, Massachusetts 02138, USA and Department of Physics, Harvard University, Cambridge, Massachusetts 02138, USA
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15
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Abstract
Over the past decade, and particularly the past five years, a quiet revolution has been building at the border between atomic physics and experimental quantum chemistry. The rapid development of techniques for producing cold and even ultracold molecules without a perturbing rare-gas cluster shell is now enabling the study of chemical reactions and scattering at the quantum scattering limit with only a few partial waves contributing to the incident channel. Moreover, the ability to perform these experiments with nonthermal distributions comprising one or a few specific states enables the observation and even full control of state-to-state collision rates in this computation-friendly regime: This is perhaps the most elementary study possible of scattering and reaction dynamics.
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Affiliation(s)
- Benjamin K Stuhl
- Joint Quantum Institute, National Institute of Standards and Technology and University of Maryland, Gaithersburg, Maryland 20899
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16
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Singh V, Hardman KS, Lu MJ, Ellis A, Morrison MJ, Weinstein JD. Inelastic collisions of CaH with He at cryogenic temperatures. Mol Phys 2013. [DOI: 10.1080/00268976.2013.772668] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Affiliation(s)
- Vijay Singh
- a Department of Physics , University of Nevada , Reno , USA
| | | | - Mei-Ju Lu
- a Department of Physics , University of Nevada , Reno , USA
| | - Aja Ellis
- a Department of Physics , University of Nevada , Reno , USA
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17
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Tariq N, Al Taisan N, Singh V, Weinstein JD. Spectroscopic detection of the LiHe molecule. PHYSICAL REVIEW LETTERS 2013; 110:153201. [PMID: 25167262 DOI: 10.1103/physrevlett.110.153201] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/27/2012] [Indexed: 06/03/2023]
Abstract
We use cryogenic helium buffer-gas cooling to form large densities of lithium atoms in a high-density helium gas, from which LiHe molecules form by three-body recombination. These weakly bound van der Waals molecules are detected spectroscopically, and their binding energy is measured from their equilibrium thermodynamic properties.
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Affiliation(s)
- Naima Tariq
- Department of Physics, University of Nevada, Reno, Nevada 89557, USA
| | - Nada Al Taisan
- Department of Physics, University of Nevada, Reno, Nevada 89557, USA
| | - Vijay Singh
- Department of Physics, University of Nevada, Reno, Nevada 89557, USA
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19
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Henson AB, Gersten S, Shagam Y, Narevicius J, Narevicius E. Observation of Resonances in Penning Ionization Reactions at Sub-Kelvin Temperatures in Merged Beams. Science 2012; 338:234-8. [DOI: 10.1126/science.1229141] [Citation(s) in RCA: 231] [Impact Index Per Article: 19.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Affiliation(s)
- A. B. Henson
- Department of Chemical Physics, Weizmann Institute of Science, Rehovot, Israel
| | - S. Gersten
- Department of Chemical Physics, Weizmann Institute of Science, Rehovot, Israel
| | - Y. Shagam
- Department of Chemical Physics, Weizmann Institute of Science, Rehovot, Israel
| | - J. Narevicius
- Department of Chemical Physics, Weizmann Institute of Science, Rehovot, Israel
| | - E. Narevicius
- Department of Chemical Physics, Weizmann Institute of Science, Rehovot, Israel
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20
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Lara M, Chefdeville S, Hickson KM, Bergeat A, Naulin C, Launay JM, Costes M. Dynamics of the S(1D2)+HD(j=0) reaction at collision energies approaching the cold regime: a stringent test for theory. PHYSICAL REVIEW LETTERS 2012; 109:133201. [PMID: 23030086 DOI: 10.1103/physrevlett.109.133201] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/29/2012] [Indexed: 06/01/2023]
Abstract
We report integral cross sections for the S(1D2)+HD(j=0)→DS+H and HS+D reaction channels obtained through crossed-beam experiments reaching collision energies as low as 0.46 meV and from adiabatic time-independent quantum-mechanical calculations. While good overall agreement with experiment at energies above 10 meV is observed, neither the product channel branching ratio nor the low-energy resonancelike features in the HS+D channel can be theoretically reproduced. A nonadiabatic treatment employing highly accurate singlet and triplet potential energy surfaces is clearly needed to resolve the complex nature of the reaction dynamics.
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Affiliation(s)
- Manuel Lara
- Departamento de Química Física Aplicada, Facultad de Ciencias, Universidad Autónoma de Madrid, 28049 Madrid, Spain
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