1
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Strasser P, Fukumura S, Iwai R, Kanda S, Kawamura S, Kitaguchi M, Nishimura S, Seo S, Shimizu HM, Shimomura K, Tada H, Torii HA. Improved Measurements of Muonic Helium Ground-State Hyperfine Structure at a Near-Zero Magnetic Field. PHYSICAL REVIEW LETTERS 2023; 131:253003. [PMID: 38181354 DOI: 10.1103/physrevlett.131.253003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/12/2023] [Revised: 10/12/2023] [Accepted: 11/15/2023] [Indexed: 01/07/2024]
Abstract
Muonic helium atom hyperfine structure (HFS) measurements are a sensitive tool to test the three-body atomic system and bound-state quantum electrodynamics theory, and determine fundamental constants of the negative muon magnetic moment and mass. The world's most intense pulsed negative muon beam at the Muon Science Facility of the Japan Proton Accelerator Research Complex allows improvement of previous measurements and testing further CPT invariance by comparing the magnetic moments and masses of positive and negative muons (second-generation leptons). We report new ground-state HFS measurements of muonic helium-4 atoms at a near-zero magnetic field, performed for the first time using a small admixture of CH_{4} as an electron donor to form neutral muonic helium atoms efficiently. Our analysis gives Δν=4464.980(20) MHz (4.5 ppm), which is more precise than both previous measurements at weak and high fields. The muonium ground-state HFS was also measured under the same conditions to investigate the isotopic effect on the frequency shift due to the gas density dependence in He with CH_{4} admixture and compared with previous studies. Muonium and muonic helium can be regarded as light and heavy hydrogen isotopes with an isotopic mass ratio of 36. No isotopic effect was observed within the current experimental precision.
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Affiliation(s)
- P Strasser
- Muon Science Laboratory, Institute of Materials Structure Science (IMSS), High Energy Accelerator Research Organization (KEK), 1-1 Oho, Tsukuba, Ibaraki 305-0801, Japan
- Muon Science Section, Materials and Life Science Division, J-PARC Center, 2-4 Shirakata, Tokai-mura, Naka-gun, Ibaraki 319-1195, Japan
- Materials Structure Science Program, Graduate Institute for Advanced Studies, SOKENDAI, 1-1 Oho, Tsukuba, Ibaraki 305-0801, Japan
| | - S Fukumura
- Department of Physics, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8601, Japan
| | - R Iwai
- Muon Science Laboratory, Institute of Materials Structure Science (IMSS), High Energy Accelerator Research Organization (KEK), 1-1 Oho, Tsukuba, Ibaraki 305-0801, Japan
| | - S Kanda
- Muon Science Laboratory, Institute of Materials Structure Science (IMSS), High Energy Accelerator Research Organization (KEK), 1-1 Oho, Tsukuba, Ibaraki 305-0801, Japan
- Muon Science Section, Materials and Life Science Division, J-PARC Center, 2-4 Shirakata, Tokai-mura, Naka-gun, Ibaraki 319-1195, Japan
- Materials Structure Science Program, Graduate Institute for Advanced Studies, SOKENDAI, 1-1 Oho, Tsukuba, Ibaraki 305-0801, Japan
| | - S Kawamura
- Department of Physics, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8601, Japan
| | - M Kitaguchi
- Department of Physics, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8601, Japan
- Kobayashi-Maskawa Institute, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8602, Japan
| | - S Nishimura
- Muon Science Laboratory, Institute of Materials Structure Science (IMSS), High Energy Accelerator Research Organization (KEK), 1-1 Oho, Tsukuba, Ibaraki 305-0801, Japan
- Muon Science Section, Materials and Life Science Division, J-PARC Center, 2-4 Shirakata, Tokai-mura, Naka-gun, Ibaraki 319-1195, Japan
| | - S Seo
- Graduate School of Arts and Sciences, The University of Tokyo, 3-8-1 Komaba, Meguro, Tokyo 153-8902, Japan
| | - H M Shimizu
- Department of Physics, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8601, Japan
| | - K Shimomura
- Muon Science Laboratory, Institute of Materials Structure Science (IMSS), High Energy Accelerator Research Organization (KEK), 1-1 Oho, Tsukuba, Ibaraki 305-0801, Japan
- Muon Science Section, Materials and Life Science Division, J-PARC Center, 2-4 Shirakata, Tokai-mura, Naka-gun, Ibaraki 319-1195, Japan
- Materials Structure Science Program, Graduate Institute for Advanced Studies, SOKENDAI, 1-1 Oho, Tsukuba, Ibaraki 305-0801, Japan
| | - H Tada
- Department of Physics, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8601, Japan
| | - H A Torii
- School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
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2
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Goli M, Shahbazian S. Two-component density functional theory for muonic molecules: Inclusion of the electron–positive muon correlation functional. J Chem Phys 2022; 156:044104. [DOI: 10.1063/5.0077179] [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)
- Mohammad Goli
- School of Nano Science, Institute for Research in Fundamental Sciences (IPM), Tehran 19395-5531, Iran
| | - Shant Shahbazian
- Department of Physics, Shahid Beheshti University, Evin, Tehran, Iran
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3
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Fang JH, Fan WB, Yang H, Song JN, Li YL. Rate coefficients and kinetic isotope effects of Cl+XCl→XCl+Cl (X=H, D, Mu) reactions from ring polymer molecular dynamics. CHINESE J CHEM PHYS 2021. [DOI: 10.1063/1674-0068/cjcp2007117] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Affiliation(s)
- Jun-hua Fang
- Department of Chemistry, Shanghai University, Shanghai 200444, China
| | - Wen-bin Fan
- Department of Physics, International Center for Quantum and Molecular Structures, and Shanghai Key Laboratory of High Temperature Superconductors, Shanghai University, Shanghai 200444, China
| | - Hui Yang
- Department of Physics, International Center for Quantum and Molecular Structures, and Shanghai Key Laboratory of High Temperature Superconductors, Shanghai University, Shanghai 200444, China
| | - Jia-ning Song
- Department of Physics, International Center for Quantum and Molecular Structures, and Shanghai Key Laboratory of High Temperature Superconductors, Shanghai University, Shanghai 200444, China
| | - Yong-le Li
- Department of Physics, International Center for Quantum and Molecular Structures, and Shanghai Key Laboratory of High Temperature Superconductors, Shanghai University, Shanghai 200444, China
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Gao LG, Fleming DG, Truhlar DG, Xu X. Large Anharmonic Effects on Tunneling and Kinetics: Reaction of Propane with Muonium. J Phys Chem Lett 2021; 12:4154-4159. [PMID: 33890795 DOI: 10.1021/acs.jpclett.1c01229] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Calculations of kinetic isotope effects (KIEs) provide challenging tests of quantal mass effects on reaction rates, and muonium KIEs are the most challenging. Here, we show that it can be very important to include reaction-coordinate-dependent vibrational anharmonicity along the whole reaction path to calculate tunneling probabilities and KIEs. For the reaction of propane with Mu, this decreases both the height and width of the vibrationally adiabatic potential barrier, with both effects increasing the rate constants. Our results agree well with the experimental observations.
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Affiliation(s)
- Lu Gem Gao
- Center for Combustion Energy, Department of Energy and Power Engineering, and Key Laboratory for Thermal Science and Power Engineering of Ministry of Education, Tsinghua University, Beijing 100084, China
| | - Donald G Fleming
- TRIUMF and Department of Chemistry, University of British Columbia, 4004 Wesbrook Mall, Vancouver, BC V6T 1Z4, Canada
| | - Donald G Truhlar
- Department of Chemistry, Chemical Theory Center, and Minnesota Supercomputing Institute, University of Minnesota, Minneapolis, Minnesota 55455-0431, United States
| | - Xuefei Xu
- Center for Combustion Energy, Department of Energy and Power Engineering, and Key Laboratory for Thermal Science and Power Engineering of Ministry of Education, Tsinghua University, Beijing 100084, China
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TAKAYANAGI T, MIYAZAKI T. An Invitation to Muon and Muonium Chemistry Research. JOURNAL OF COMPUTER CHEMISTRY-JAPAN 2020. [DOI: 10.2477/jccj.2020-0009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Affiliation(s)
- Toshiyuki TAKAYANAGI
- Department of Chemistry, Saitama University 255 Shimo-Okubo, Saitama City, Saitama 338-8570 JAPAN
| | - Takaaki MIYAZAKI
- Department of Chemistry, Saitama University 255 Shimo-Okubo, Saitama City, Saitama 338-8570 JAPAN
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Fleming DG, Arseneau DJ, Cottrell SP, Peck JNT. Rate constants and kinetic isotope effects for H-atom abstraction reactions by muonium in the Mu + propane and Mu + n-butane reactions from 300 K to 435 K: challenges for theory. Phys Chem Chem Phys 2020; 22:6326-6334. [DOI: 10.1039/c9cp06822h] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
This paper reports measurements of the temperature dependence of the rate constants for H-atom abstraction reactions from propane and n-butane by the light isotopic H-atom muonium (Mu), kMu(T), over temperatures in the range 300 K to 435 K.
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Affiliation(s)
- Donald G. Fleming
- TRIUMF and Department of Chemistry
- University of British Columbia
- Vancouver
- Canada
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Ghandi K, Landry C, Du T, Lainé M, Saul A, Le Caër S. Influence of confinement on free radical chemistry in layered nanostructures. Sci Rep 2019; 9:17165. [PMID: 31748626 PMCID: PMC6868163 DOI: 10.1038/s41598-019-52662-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2019] [Accepted: 10/18/2019] [Indexed: 11/08/2022] Open
Abstract
The purpose of the present work was to study how chemical reactions and the electronic structure of atoms are affected by confinement at the sub-nanometer scale. To reach this goal, we studied the H atom in talc, a layered clay mineral. Talc is a highly 2D-confining material with the width of its interlayer space close to angstrom. We investigated talc with a particle accelerator-based spectroscopic method that uses elementary particles. This technique generates an exotic atom, muonium (Mu), which can be considered as an isotope of the H atom. Moreover, the technique allows us to probe a single atom (H atom) at any time and explore the effects of the layered clay on a single ion (proton) or atom. The cation/electron recombination happens in two time windows: one faster than a nanosecond and the other one at longer than microseconds. This result suggests that two types of electron transfer processes take place in these clay minerals. Calculations demonstrated that the interlayer space acts as a catalytic surface and is the primary location of cation/electron recombination in talc. Moreover, the studies of the temperature dependence of Mu decay rates, due to the formation of the surrogate of H2, is suggestive of an "H2" formation reaction that is thermally activated above 25 K, but governed by quantum diffusion below 25 K. The experimental and computational studies of the hyperfine coupling constant of Mu suggest that it is formed in the interlayer space of talc and that its electronic structure is extremely changed due to confinement. All these results imply that the chemistry could be strongly affected by confinement in the interlayer space of clays.
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Affiliation(s)
- Khashayar Ghandi
- University of Guelph, Department of chemistry, Guelph, ON, N1G 2W1, Canada.
| | - Cody Landry
- University of Guelph, Department of chemistry, Guelph, ON, N1G 2W1, Canada
| | - Tait Du
- Université de Sherbrooke, Faculté de médecine, Sherbrooke, QC, J1H 5N4, Canada
| | - Maxime Lainé
- LIONS, NIMBE, CEA, CNRS, Université Paris Saclay, CEA Saclay, F-91191, Gif-sur-Yvette, Cedex, France
| | - Andres Saul
- Aix-Marseille University, CINaM-CNRS UMR 7325 Campus de Luminy, F-13288, Marseille, Cedex 9, France
| | - Sophie Le Caër
- LIONS, NIMBE, CEA, CNRS, Université Paris Saclay, CEA Saclay, F-91191, Gif-sur-Yvette, Cedex, France
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8
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Sang JW, Yuan DF, Chen WT, Yu SR, Luo C, Wang SW, Wang T, Yang XM, Wang XA. High resolution crossed molecular beams study of the H+HD→H2+D reaction. CHINESE J CHEM PHYS 2019. [DOI: 10.1063/1674-0068/cjcp1901010] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Affiliation(s)
- Ji-wei Sang
- Department of Chemical Physics, University of Science and Technology of China, Hefei 230026, China
| | - Dao-fu Yuan
- Department of Chemical Physics, University of Science and Technology of China, Hefei 230026, China
| | - Wen-tao Chen
- Department of Chemical Physics, University of Science and Technology of China, Hefei 230026, China
| | - Sheng-rui Yu
- Hangzhou Institute of Advanced Studies, Zhejiang Normal University, Hangzhou 311231, China
| | - Chang Luo
- Department of Chemical Physics, University of Science and Technology of China, Hefei 230026, China
| | - Si-wen Wang
- Department of Chemical Physics, University of Science and Technology of China, Hefei 230026, China
| | - Tao Wang
- Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China
- Department of Chemistry, School of Science, Southern University of Science and Technology, Shenzhen 518055, China
| | - Xue-ming Yang
- Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China
- Department of Chemistry, School of Science, Southern University of Science and Technology, Shenzhen 518055, China
| | - Xing-an Wang
- Department of Chemical Physics, University of Science and Technology of China, Hefei 230026, China
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9
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Song Y, Liu R, Guan Y, Gao J, Lou J, Ma H, Song J. Computational Study of the Reaction of Dimethyl Ether with Nitric Oxide. Mechanism and Kinetic Modeling. J Phys Chem A 2019; 123:26-36. [DOI: 10.1021/acs.jpca.8b09953] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Yiming Song
- School of Chemical Engineering, Northwest University, Xi’an 710069, China
| | - Ru Liu
- School of Chemical Engineering, Northwest University, Xi’an 710069, China
| | - Yulei Guan
- School of Chemical Engineering, Northwest University, Xi’an 710069, China
| | - Jing Gao
- School of Chemical Engineering, Northwest University, Xi’an 710069, China
| | - Junpeng Lou
- School of Chemical Engineering, Northwest University, Xi’an 710069, China
| | - Haixia Ma
- School of Chemical Engineering, Northwest University, Xi’an 710069, China
| | - Jirong Song
- School of Chemical Engineering, Northwest University, Xi’an 710069, China
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10
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Charry J, Varella MTDN, Reyes A. Binding Matter with Antimatter: The Covalent Positron Bond. Angew Chem Int Ed Engl 2018; 57:8859-8864. [DOI: 10.1002/anie.201800914] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2018] [Indexed: 11/09/2022]
Affiliation(s)
- Jorge Charry
- Universidad Nacional de Colombia Chemistry; Av. cra 30 #45-03 Bogota, 00000 Colombia
| | - Márcio T. do N. Varella
- Instituto de Física; Universidade de São Paulo; Rua do Matão 1731 05508-090 São Paulo, SP Brazil
| | - Andrés Reyes
- Universidad Nacional de Colombia Chemistry; Av. cra 30 #45-03 Bogota, 00000 Colombia
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11
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12
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Direct observation of forward-scattering oscillations in the H+HD→H2+D reaction. Nat Chem 2018; 10:653-658. [DOI: 10.1038/s41557-018-0032-9] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2017] [Accepted: 02/21/2018] [Indexed: 11/08/2022]
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13
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Posada E, Moncada F, Reyes A. The any particle molecular orbital grid-based Hartree-Fock (APMO-GBHF) approach. J Chem Phys 2018; 148:084113. [PMID: 29495795 DOI: 10.1063/1.5012521] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Affiliation(s)
- Edwin Posada
- Departament of Chemistry, Universidad Nacional de Colombia, Ave. Cra. 30, #45-03 Bogotá, Colombia
| | - Félix Moncada
- Departament of Chemistry, Universidad Nacional de Colombia, Ave. Cra. 30, #45-03 Bogotá, Colombia
| | - Andrés Reyes
- Departament of Chemistry, Universidad Nacional de Colombia, Ave. Cra. 30, #45-03 Bogotá, Colombia
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14
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Lu D, Zhang Y, Li J. Kinetics studies of the F + HCl → HF + Cl reaction on an accurate potential energy surface. Chem Phys Lett 2018. [DOI: 10.1016/j.cplett.2017.11.014] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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15
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Wang K, Murahari P, Yokoyama K, Lord JS, Pratt FL, He J, Schulz L, Willis M, Anthony JE, Morley NA, Nuccio L, Misquitta A, Dunstan DJ, Shimomura K, Watanabe I, Zhang S, Heathcote P, Drew AJ. Temporal mapping of photochemical reactions and molecular excited states with carbon specificity. NATURE MATERIALS 2017; 16:467-473. [PMID: 27941808 DOI: 10.1038/nmat4816] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/16/2016] [Accepted: 10/31/2016] [Indexed: 06/06/2023]
Abstract
Photochemical reactions are essential to a large number of important industrial and biological processes. A method for monitoring photochemical reaction kinetics and the dynamics of molecular excitations with spatial resolution within the active molecule would allow a rigorous exploration of the pathway and mechanism of photophysical and photochemical processes. Here we demonstrate that laser-excited muon pump-probe spin spectroscopy (photo-μSR) can temporally and spatially map these processes with a spatial resolution at the single-carbon level in a molecule with a pentacene backbone. The observed time-dependent light-induced changes of an avoided level crossing resonance demonstrate that the photochemical reactivity of a specific carbon atom is modified as a result of the presence of the excited state wavefunction. This demonstrates the sensitivity and potential of this technique in probing molecular excitations and photochemistry.
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Affiliation(s)
- K Wang
- College of Physical Sciences and Technology, Sichuan University, Chengdu, Sichuan 610064, China
- School of Physics and Astronomy, Queen Mary University of London, Mile End, London E1 4NS, UK
| | - P Murahari
- School of Physics and Astronomy, Queen Mary University of London, Mile End, London E1 4NS, UK
| | - K Yokoyama
- School of Physics and Astronomy, Queen Mary University of London, Mile End, London E1 4NS, UK
- ISIS Muon Facility, Rutherford Appleton Laboratory, Didcot OX11 0QX, UK
| | - J S Lord
- ISIS Muon Facility, Rutherford Appleton Laboratory, Didcot OX11 0QX, UK
| | - F L Pratt
- ISIS Muon Facility, Rutherford Appleton Laboratory, Didcot OX11 0QX, UK
| | - J He
- College of Physical Sciences and Technology, Sichuan University, Chengdu, Sichuan 610064, China
| | - L Schulz
- College of Physical Sciences and Technology, Sichuan University, Chengdu, Sichuan 610064, China
| | - M Willis
- College of Physical Sciences and Technology, Sichuan University, Chengdu, Sichuan 610064, China
| | - J E Anthony
- Department of Chemistry, University of Kentucky, Lexington, Kentucky 40506, USA
| | - N A Morley
- Department of Materials Science and Engineering, University of Sheffield, Sheffield S1 3JD, UK
| | - L Nuccio
- University of Fribourg, Department of Physics and Fribourg Centre for Nanomaterials, Chemin du Museé 3, CH-1700 Fribourg, Switzerland
| | - A Misquitta
- School of Physics and Astronomy, Queen Mary University of London, Mile End, London E1 4NS, UK
| | - D J Dunstan
- School of Physics and Astronomy, Queen Mary University of London, Mile End, London E1 4NS, UK
| | - K Shimomura
- Materials and Life Science Division, J-PARC Center, Tokai, Ibaraki 319-1195, Japan
| | - I Watanabe
- RIKEN-RAL, Nishina Centre, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - S Zhang
- College of Physical Sciences and Technology, Sichuan University, Chengdu, Sichuan 610064, China
| | - P Heathcote
- School of Biological and Chemical Sciences, Queen Mary University of London, Mile End, London E1 4NS, UK
| | - A J Drew
- College of Physical Sciences and Technology, Sichuan University, Chengdu, Sichuan 610064, China
- School of Physics and Astronomy, Queen Mary University of London, Mile End, London E1 4NS, UK
- ISIS Muon Facility, Rutherford Appleton Laboratory, Didcot OX11 0QX, UK
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16
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Guan Y, Li Y, Zhao L, Ma H, Song J. Understanding and modeling the hydrogen-abstraction from dimethyl ether by the methyl radical with torsional anharmonicity. COMPUT THEOR CHEM 2016. [DOI: 10.1016/j.comptc.2016.09.030] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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17
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Guan Y, Li Y, Zhao L, Song Y, Ma H, Song J. Hydrogen transfer between dimethyl ether and the methoxy radical: Understanding and kinetic modeling with anharmonic torsions. COMPUT THEOR CHEM 2016. [DOI: 10.1016/j.comptc.2016.05.011] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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18
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Mustroph H. Potential-Energy Surfaces, the Born-Oppenheimer Approximations, and the Franck-Condon Principle: Back to the Roots. Chemphyschem 2016; 17:2616-29. [DOI: 10.1002/cphc.201600243] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2016] [Revised: 05/12/2016] [Indexed: 11/11/2022]
Affiliation(s)
- Heinz Mustroph
- FEW Chemicals GmbH; Technikumstraße 1 06756 Bitterfeld-Wolfen Germany
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19
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Jayachander Rao B, Varandas A. Sub-femtosecond nuclear dynamics and high-harmonic generation: Can muonated species be used as a probe of isotope effects? Chem Phys Lett 2016. [DOI: 10.1016/j.cplett.2016.03.057] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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20
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González-Lafont À, Lluch JM. Kinetic isotope effects in chemical and biochemical reactions: physical basis and theoretical methods of calculation. WILEY INTERDISCIPLINARY REVIEWS-COMPUTATIONAL MOLECULAR SCIENCE 2016. [DOI: 10.1002/wcms.1268] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Affiliation(s)
- Àngels González-Lafont
- Institut de Biotecnologia i de Biomedicina and Departament de Química; Universitat Autònoma de Barcelona; Bellaterra, Barcelona Spain
| | - José M. Lluch
- Institut de Biotecnologia i de Biomedicina and Departament de Química; Universitat Autònoma de Barcelona; Bellaterra, Barcelona Spain
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21
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Sáez-Rábanos V, Verdasco JE, Aoiz FJ, Herrero VJ. Influence of vibration in the reactive scattering of D + MuH: the effect of dynamical bonding. Phys Chem Chem Phys 2016; 18:13530-7. [PMID: 27138743 PMCID: PMC4931899 DOI: 10.1039/c6cp01305h] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The dynamics of the D + MuH(v = 1) reaction has been investigated using time-independent quantum mechanical calculations. The total reaction cross sections and rate coefficients have been calculated for the two exit channels of the reaction leading, respectively, to DMu + H and DH + Mu. Over the 100-1000 K temperature range investigated the rate coefficients for the DMu + H channel are of the order of 10(-10) cm(3) s(-1) and those for the DH + Mu channel vary between 1 × 10(-12) and 8 × 10(-11) cm(3) s(-1). These results point to a virtually barrierless reaction for the DMu + H channel and to the presence of a comparatively small barrier for the DH + Mu channel and are consistent with the profiles of their respective collinear vibrationally adiabatic potentials (VAPs). The effective barrier in the VAP of the DH + Mu channel is located in the reactant valley and, consequently, translation is found to be more efficient than vibration for the promotion of the reaction over a large energy interval in the post threshold region. Below this barrier, the DH + Mu channel can be accessible through an indirect mechanism implying crossing from the DMu + H pathway. The most salient feature found in the present study is revealed in the total reaction cross section for the DMu + H channel, which shows a sharp resonance caused by the presence of a deep well in the vibrationally adiabatic potential. This well has a dynamical origin, reminiscent of that found recently in the vibrationally bonded BrMuBr complex [Fleming, et al., Angew. Chem., Int. Ed., 2014, 53, 1], and is due to the stabilizing effect of the light Mu atom oscillating between the heavier H and D isotopes and to the bond softening associated with vibrational excitation of MuH.
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Affiliation(s)
- V Sáez-Rábanos
- Departamento de Sistemas y Recursos Naturales. E.T.S. de Ingeniería de Montes, Forestal y del Medio Natural, Universidad Politécnica de Madrid, 28040 Madrid, Spain.
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Goli M, Shahbazian S. Muon-Substituted Malonaldehyde: Transforming a Transition State into a Stable Structure by Isotope Substitution. Chemistry 2016; 22:2525-31. [PMID: 26749489 DOI: 10.1002/chem.201504318] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2015] [Indexed: 12/25/2022]
Abstract
Isotope substitutions are usually conceived to play a marginal role on the structure and bonding pattern of molecules. However, a recent study [Angew. Chem. Int. Ed. 2014, 53, 13706-13709; Angew. Chem. 2014, 126, 13925-13929] further demonstrates that upon replacing a proton with a positively charged muon, as the lightest radioisotope of hydrogen, radical changes in the nature of the structure and bonding of certain species may take place. The present report is a primary attempt to introduce another example of structural transformation on the basis of the malonaldehyde system. Accordingly, upon replacing the proton between the two oxygen atoms of malonaldehyde with the positively charged muon a serious structural transformation is observed. By using the ab initio nuclear-electronic orbital non-Born-Oppenheimer procedure, the nuclear configuration of the muon-substituted species is derived. The resulting nuclear configuration is much more similar to the transition state of the proton transfer in malonaldehyde rather than to the stable configuration of malonaldehyde. The comparison of the "atoms in molecules" (AIM) structure of the muon-substituted malonaldehyde and the AIM structure of the stable and the transition-state configurations of malonaldehyde also unequivocally demonstrates substantial similarities of the muon-substituted malonaldehyde to the transition state.
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Affiliation(s)
- Mohammad Goli
- Faculty of Chemistry, Shahid Beheshti University, G. C., Evin, P.O. Box 19395-4716, Tehran, 19839, Iran), Fax
| | - Shant Shahbazian
- Faculty of Chemistry, Shahid Beheshti University, G. C., Evin, P.O. Box 19395-4716, Tehran, 19839, Iran), Fax.
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TAKAYANAGI T, YOSHIDA T. New Perspectives in Muonium Chemical Reactions. JOURNAL OF COMPUTER CHEMISTRY-JAPAN 2016. [DOI: 10.2477/jccj.2016-0006] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Affiliation(s)
- Toshiyuki TAKAYANAGI
- Department of Chemistry, Saitama University 255 Shimo-Okubo, Saitama City, Saitama 338-8570 JAPAN
| | - Takahiko YOSHIDA
- Department of Chemistry, Saitama University 255 Shimo-Okubo, Saitama City, Saitama 338-8570 JAPAN
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Arseneau DJ, Fleming DG, Li Y, Li J, Suleimanov YV, Guo H. Rate Coefficient for the 4Heμ + CH4 Reaction at 500 K: Comparison between Theory and Experiment. J Phys Chem B 2015; 120:1641-8. [DOI: 10.1021/acs.jpcb.5b08368] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Donald J. Arseneau
- TRIUMF
and Department of Chemistry, University of British Columbia, Vancouver, BC V6T 2Z1, Canada
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25
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Teixidor MM, Varandas AJ. Quantum dynamics study of the X+O2 reactions on the CHIPR potential energy surface: X=Mu, H, D, T. Chem Phys Lett 2015. [DOI: 10.1016/j.cplett.2015.08.028] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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26
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Yoshida T, Sato K, Takayanagi T. First-principles simulations of transition state spectra of the I + HI and I + DI reactions and vibrational bonding in IMuI. Chem Phys 2015. [DOI: 10.1016/j.chemphys.2015.05.019] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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27
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Goli M, Shahbazian S. Where to place the positive muon in the Periodic Table? Phys Chem Chem Phys 2015; 17:7023-37. [PMID: 25684734 DOI: 10.1039/c4cp06006g] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
In a recent study it was suggested that the positively charged muon is capable of forming its own "atoms in molecules" (AIM) in the muonic hydrogen-like molecules, composed of two electrons, a muon and one of the hydrogen's isotopes, thus deserves to be placed in the Periodic Table [Phys. Chem. Chem. Phys., 2014, 16, 6602]. In the present report, the capacity of the positively charged muon in forming its own AIM is considered in a large set of molecules replacing muons with all protons in the hydrides of the second and third rows of the Periodic Table. Accordingly, in a comparative study the wavefunctions of both sets of hydrides and their muonic congeners are first derived beyond the Born-Oppenheimer (BO) paradigm, assuming protons and muons as quantum waves instead of clamped particles. Then, the non-BO wavefunctions are used to derive the AIM structures of both hydrides and muonic congeners within the context of the multi-component quantum theory of atoms in molecules. The results of the analysis demonstrate that muons are generally capable of forming their own atomic basins and the properties of these basins are not fundamentally different from those AIM containing protons. Particularly, the bonding modes in the muonic species seem to be qualitatively similar to their congener hydrides and no new bonding model is required to describe the bonding of muons to a diverse set of neighboring atoms. All in all, the positively charged muon is similar to a proton from the structural and bonding viewpoint and deserves to be placed in the same box of hydrogen in the Periodic Table. This conclusion is in line with a large body of studies on the chemical kinetics of the muonic molecules portraying the positively charged muon as a lighter isotope of hydrogen.
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Affiliation(s)
- Mohammad Goli
- Faculty of Chemistry, Shahid Beheshti University, G. C., Evin, P.O. Box 19395-4716, Tehran, 19839, Iran.
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28
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Arseneau DJ, Garner DM, Reid ID, Fleming DG. Muonium Addition Reactions and Kinetic Isotope Effects in the Gas Phase: k∞ Rate Constants for Mu + C2H2. J Phys Chem A 2015; 119:7247-56. [DOI: 10.1021/jp511604q] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Donald J. Arseneau
- TRIUMF and Department of
Chemistry, University of British Columbia, Vancouver, BC, Canada
| | - David M. Garner
- TRIUMF and Department of
Chemistry, University of British Columbia, Vancouver, BC, Canada
| | - Ivan D. Reid
- TRIUMF and Department of
Chemistry, University of British Columbia, Vancouver, BC, Canada
| | - Donald G. Fleming
- TRIUMF and Department of
Chemistry, University of British Columbia, Vancouver, BC, Canada
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29
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Fleming DG, Cottrell SP, McKenzie I, Ghandi K. Rate constants for the slow Mu + propane abstraction reaction at 300 K by diamagnetic RF resonance. Phys Chem Chem Phys 2015; 17:19901-10. [DOI: 10.1039/c5cp02576a] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The rate constant for the slow Mu + propane abstraction reaction has been determined by diamagnetic RF resonance. The curves show simulations of the μSR resonance signal. This study provides an important new test of reaction rate theory for the alkanes.
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Affiliation(s)
- Donald G. Fleming
- TRIUMF Laboratory and Department of Chemistry
- University of British Columbia
- Vancouver
- Canada
| | | | - Iain McKenzie
- ISIS Facility
- STFC Rutherford Appleton Laboratory
- Didcot
- UK
- CMMS Facility
| | - Khashayar Ghandi
- Department of Chemistry and Biochemistry
- Mount Allison University
- Sackville
- Canada
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30
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Fleming DG, Manz J, Sato K, Takayanagi T. Über eine fundamentale Änderung der Art der chemischen Bindung durch Isotopensubstitution. Angew Chem Int Ed Engl 2014. [DOI: 10.1002/ange.201408211] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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31
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Fleming DG, Manz J, Sato K, Takayanagi T. Fundamental Change in the Nature of Chemical Bonding by Isotopic Substitution. Angew Chem Int Ed Engl 2014; 53:13706-9. [DOI: 10.1002/anie.201408211] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2014] [Indexed: 11/10/2022]
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32
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Mielke SL, Garrett BC, Fleming DG, Truhlar DG. Zero-point energy, tunnelling, and vibrational adiabaticity in the Mu + H2reaction. Mol Phys 2014. [DOI: 10.1080/00268976.2014.951416] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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33
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Nattino F, Genova A, Guijt M, Muzas AS, Díaz C, Auerbach DJ, Kroes GJ. Dissociation and recombination of D2 on Cu(111): Ab initio molecular dynamics calculations and improved analysis of desorption experiments. J Chem Phys 2014; 141:124705. [DOI: 10.1063/1.4896058] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Francesco Nattino
- Leiden Institute of Chemistry, Leiden University, Gorlaeus Laboratories, P.O. Box 9502, 2300 RA Leiden, The Netherlands
| | - Alessandro Genova
- Leiden Institute of Chemistry, Leiden University, Gorlaeus Laboratories, P.O. Box 9502, 2300 RA Leiden, The Netherlands
| | - Marieke Guijt
- Leiden Institute of Chemistry, Leiden University, Gorlaeus Laboratories, P.O. Box 9502, 2300 RA Leiden, The Netherlands
| | - Alberto S. Muzas
- Departamento de Química Módulo 13, Universitad Autónoma de Madrid, 28049 Madrid, Spain
| | - Cristina Díaz
- Departamento de Química Módulo 13, Universitad Autónoma de Madrid, 28049 Madrid, Spain
| | - Daniel J. Auerbach
- Leiden Institute of Chemistry, Leiden University, Gorlaeus Laboratories, P.O. Box 9502, 2300 RA Leiden, The Netherlands
- Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
| | - Geert-Jan Kroes
- Leiden Institute of Chemistry, Leiden University, Gorlaeus Laboratories, P.O. Box 9502, 2300 RA Leiden, The Netherlands
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34
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Liu C, Manz J, Yang Y. Laser Sculpting of Atomic sp, sp2, and sp3Hybrid Orbitals. Chemphyschem 2014; 16:191-6. [DOI: 10.1002/cphc.201402588] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2014] [Indexed: 11/09/2022]
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35
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Posada E, Moncada F, Reyes A. Negative Muon Chemistry: The Quantum Muon Effect and the Finite Nuclear Mass Effect. J Phys Chem A 2014; 118:9491-9. [DOI: 10.1021/jp501289s] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Edwin Posada
- Departamento
de Química, Universidad Nacional de Colombia, Av. Cra.
30 #45-03, Bogotá, Colombia
| | - Félix Moncada
- Departamento
de Química, Universidad Nacional de Colombia, Av. Cra.
30 #45-03, Bogotá, Colombia
- Programa
de Química, Universidad de la Amazonia, Calle 17 Diagonal 17 - Carrera 3F, Florencia, Colombia
| | - Andrés Reyes
- Departamento
de Química, Universidad Nacional de Colombia, Av. Cra.
30 #45-03, Bogotá, Colombia
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36
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Goli M, Shahbazian S. Deciphering the "chemical" nature of the exotic isotopes of hydrogen by the MC-QTAIM analysis: the positively charged muon and the muonic helium as new members of the periodic table. Phys Chem Chem Phys 2014; 16:6602-13. [PMID: 24569859 DOI: 10.1039/c3cp55162h] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
This report is a primarily survey on the chemical nature of some exotic species containing the positively charged muon and the muonic helium, i.e., the negatively charged muon plus helium nucleus, as exotic isotopes of hydrogen, using the newly developed multi-component quantum theory of atoms in molecules (MC-QTAIM) analysis, employing ab initio non-Born-Oppenhiemer wavefunctions. Accordingly, the "atoms in molecules" analysis performed on various asymmetric exotic isotopomers of the hydrogen molecule, recently detected experimentally [Science, 2011, 331, 448], demonstrates that both the exotic isotopes are capable of forming atoms in molecules and retaining the identity of hydrogen atoms. Various derived properties of atomic basins containing the muonic helium cast no doubt that apart from its short life time, it is a heavier isotope of hydrogen while the properties of basins containing the positively charged muon are more remote from those of the orthodox hydrogen basins, capable of appreciable donation of electrons as well as large charge polarization. However, with some tolerance, they may also be categorized as hydrogen basins though with a smaller electronegativity. All in all, the present study also clearly demonstrates that the MC-QTAIM analysis is an efficient approach to decipher the chemical nature of species containing exotic constituents, which are difficult to elucidate by experimental and/or alternative theoretical schemes.
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Affiliation(s)
- Mohammad Goli
- Faculty of Chemistry, Shahid Beheshti University, G. C., Evin, P.O. Box 19395-4716, 19839, Tehran, Iran.
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37
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Cormier PJ, Clarke RM, McFadden RML, Ghandi K. Selective free radical reactions using supercritical carbon dioxide. J Am Chem Soc 2014; 136:2200-3. [PMID: 24476090 DOI: 10.1021/ja408438s] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We report herein a means to modify the reactivity of alkenes, and particularly to modify their selectivity toward reactions with nonpolar reactants (e.g., nonpolar free radicals) in supercritical carbon dioxide near the critical point. Rate constants for free radical addition of the light hydrogen isotope muonium to ethylene, vinylidene fluoride, and vinylidene chloride in supercritical carbon dioxide are compared over a range of pressures and temperatures. Near carbon dioxide's critical point, the addition to ethylene exhibits critical speeding up, while the halogenated analogues display critical slowing. This suggests that supercritical carbon dioxide as a solvent may be used to tune alkene chemistry in near-critical conditions.
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Affiliation(s)
- Philip J Cormier
- Department of Chemistry and Biochemistry, Mount Allison University , 63C York Street, Sackville, New Brunswick E4L 1G8, Canada
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38
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Aoiz FJ, Aldegunde J, Herrero VJ, Sáez-Rábanos V. Comparative dynamics of the two channels of the reaction of D + MuH. Phys Chem Chem Phys 2014; 16:9808-18. [DOI: 10.1039/c3cp53908c] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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39
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de Oliveira-Filho AGS, Ornellas FR, Peterson KA, Mielke SL. Thermal Rate Constants for the O(3P) + HBr and O(3P) + DBr Reactions: Transition-State Theory and Quantum Mechanical Calculations. J Phys Chem A 2013; 117:12703-10. [DOI: 10.1021/jp4090684] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Antonio G. S. de Oliveira-Filho
- Departamento
de Química Fundamental, Instituto de Química, Universidade de São Paulo, Av. Prof. Lineu Prestes 748, São Paulo 05508-000, Brazil
| | - Fernando R. Ornellas
- Departamento
de Química Fundamental, Instituto de Química, Universidade de São Paulo, Av. Prof. Lineu Prestes 748, São Paulo 05508-000, Brazil
| | - Kirk A. Peterson
- Department
of Chemistry, Washington State University, Pullman, Washington 99164-4630, United States
| | - Steven L. Mielke
- Department
of Chemistry, University of Minnesota, Minneapolis, Minnesota 55455-0431, United States
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40
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The two-component quantum theory of atoms in molecules (TC-QTAIM): the unified theory of localization/delocalization of electrons, nuclei, and exotic elementary particles. Theor Chem Acc 2013. [DOI: 10.1007/s00214-013-1410-4] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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41
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Aldegunde J, Jambrina P, García E, Herrero V, Sáez-Rábanos V, Aoiz F. Understanding the reaction between muonium atoms and hydrogen molecules: zero point energy, tunnelling, and vibrational adiabaticity. Mol Phys 2013. [DOI: 10.1080/00268976.2013.815399] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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42
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43
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Tsai WC, Hu WP. Theoretical analysis on the kinetic isotope effects of bimolecular nucleophilic substitution (S(N)2) reactions and their temperature dependence. Molecules 2013; 18:4816-43. [PMID: 23612475 PMCID: PMC6270110 DOI: 10.3390/molecules18044816] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2013] [Revised: 04/03/2013] [Accepted: 04/18/2013] [Indexed: 11/30/2022] Open
Abstract
Factors affecting the kinetic isotope effects (KIEs) of the gas-phase S(N)2 reactions and their temperature dependence have been analyzed using the ion-molecule collision theory and the transition state theory (TST). The quantum-mechanical tunneling effects were also considered using the canonical variational theory with small curvature tunneling (CVT/SCT). We have benchmarked a few ab initio and density functional theory (DFT) methods for their performance in predicting the deuterium KIEs against eleven experimental values. The results showed that the MP2/aug-cc-pVDZ method gave the most accurate prediction overall. The slight inverse deuterium KIEs usually observed for the gas-phase S(N)2 reactions at room temperature were due to the balance of the normal rotational contribution and the significant inverse vibrational contribution. Since the vibrational contribution is a sensitive function of temperature while the rotation contribution is temperature independent, the KIEs are thus also temperature dependent. For S(N)2 reactions with appreciable barrier heights, the tunneling effects were predicted to contribute significantly both to the rate constants and to the carbon-13, and carbon-14 KIEs, which suggested important carbon atom tunneling at and below room temperature.
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Affiliation(s)
| | - Wei-Ping Hu
- Department of Chemistry and Biochemistry, National Chung Cheng University, Chia-Yi 621, Taiwan
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44
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Li Y, Suleimanov YV, Li J, Green WH, Guo H. Rate coefficients and kinetic isotope effects of the X + CH4 → CH3 + HX (X = H, D, Mu) reactions from ring polymer molecular dynamics. J Chem Phys 2013; 138:094307. [DOI: 10.1063/1.4793394] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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45
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Glowacki DR, Lightfoot R, Harvey JN. Non-equilibrium phenomena and molecular reaction dynamics: mode space, energy space and conformer space. Mol Phys 2013. [DOI: 10.1080/00268976.2013.780100] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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46
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Abstract
Hydrogen has a central role in the story of the universe itself and also in the story of our efforts to understand it. This paper retells the story of the part played by hydrogen and its stable isotope deuterium in the primordial synthesis of the elements, then goes on to describe how the spectrum of atomic hydrogen led to insights into the laws governing matter at the most fundamental level, from the quantum mechanics of Schrödinger and Heisenberg, through quantum electrodynamics, to the most recent work investigating the underlying structure of the proton itself. Atomic hydrogen is unique among the elements in that the concept of isotopy--atoms having the same nuclear charge but different masses--is stretched to its limit in the isotopes of hydrogen, ranging from the well-known isotopes deuterium and tritium to exotic species such as muonium, muonic helium, and positronium. These atoms, or atom-like objects, have much to tell us about fundamental aspects of the universe. In recent years the idea of utilizing hydrogen either as an energy source (through nuclear fusion) or as an energy storage medium (bound in hydrides or other materials) has attracted much attention as a possible avenue to a post-oil energy future. Some of the more interesting recent developments are described here. Dedicated to the memory of Brian C. Webster (1939-2008).
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Affiliation(s)
- Roderick M Macrae
- School of Mathematics and Sciences, Marian University, Indianapolis, Indiana 46222, USA.
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47
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Jambrina PG, García E, Herrero VJ, Sáez-Rábanos V, Aoiz FJ. Dynamics of the reactions of muonium and deuterium atoms with vibrationally excited hydrogen molecules: tunneling and vibrational adiabaticity. Phys Chem Chem Phys 2012; 14:14596-604. [PMID: 23019575 DOI: 10.1039/c2cp42130e] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Quantum mechanical (QM) and quasiclassical trajectory (QCT) calculations have been carried out for the exchange reactions of D and Mu (Mu = muonium) with hydrogen molecules in their ground and first vibrational states. In all the cases considered, the QM rate coefficients, k(T), are in very good agreement with the available experimental results. In particular, QM calculations on the most accurate potential energy surfaces (PESs) predict a rate coefficient for the Mu + H(2) (ν = 1) reaction which is very close to the preliminary estimate of its experimental value at 300 K. In contrast to the D + H(2) (ν = 0,1) and the Mu + H(2) (ν = 0) reactions, the QCT calculations for Mu + H(2) (ν = 1) predict a much smaller k(T) than that obtained with the accurate QM method. This behaviour is indicative of tunneling. The QM reaction probabilities and total reactive cross sections show that the total energy thresholds for the reactions of Mu with H(2) in ν = 0 and ν = 1 are very similar, whereas for the corresponding reaction with D the ν = 0 total energy threshold is about 0.3 eV lower than that for ν = 1. The results just mentioned can be explained by considering the vibrational adiabatic potentials along the minimum energy path. The threshold for the reaction of Mu with H(2) in both ν = 0 and ν = 1 states is the same and is given by the height of the ground vibrational adiabatic collinear potential, whereas for the D + H(2) reaction the adiabaticity is preserved and the threshold for the reaction in ν = 1 is very close to the height of the ν = 1 adiabatic collinear barrier. For Mu + H(2) (ν = 1) the reaction takes place by crossing from the ν = 1 to the ν = 0 adiabat, since the exit channel leading to MuH (ν = 1) is not energetically accessible. At the lowest possible energies, the non-adiabatic vibrational crossing implies a strong tunneling effect through the ν = 1 adiabatic barrier. Absence of tunneling in the classical calculations results in a threshold that coincides with the height of the ν = 1 adiabatic barrier. Most interestingly, the expected tunneling effect in the reaction of Mu with hydrogen molecules occurs for H(2) (ν = 1) but not for H(2) (ν = 0) where zero-point-energy effects clearly dominate.
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Affiliation(s)
- P G Jambrina
- Departamento de Química Física, Facultad de Química, Universidad Complutense (Unidad Asociada CSIC), 28040 Madrid, Spain
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48
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Glowacki DR, Lockhart J, Blitz MA, Klippenstein SJ, Pilling MJ, Robertson SH, Seakins PW. Interception of excited vibrational quantum states by O2 in atmospheric association reactions. Science 2012; 337:1066-9. [PMID: 22936771 DOI: 10.1126/science.1224106] [Citation(s) in RCA: 69] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Bimolecular reactions in Earth's atmosphere are generally assumed to proceed between reactants whose internal quantum states are fully thermally relaxed. Here, we highlight a dramatic role for vibrationally excited bimolecular reactants in the oxidation of acetylene. The reaction proceeds by preliminary adduct formation between the alkyne and OH radical, with subsequent O(2) addition. Using a detailed theoretical model, we show that the product-branching ratio is determined by the excited vibrational quantum-state distribution of the adduct at the moment it reacts with O(2). Experimentally, we found that under the simulated atmospheric conditions O(2) intercepts ~25% of the excited adducts before their vibrational quantum states have fully relaxed. Analogous interception of excited-state radicals by O(2) is likely common to a range of atmospheric reactions that proceed through peroxy complexes.
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Abstract
One of the most controversial questions in enzymology today is whether protein dynamics are significant in enzyme catalysis. A particular issue in these debates is the unusual temperature-dependence of some kinetic isotope effects for enzyme-catalysed reactions. In the present paper, we review our recent model [Glowacki, Harvey and Mulholland (2012) Nat. Chem. 4, 169-176] that is capable of reproducing intriguing temperature-dependences of enzyme reactions involving significant quantum tunnelling. This model relies on treating multiple conformations of the enzyme-substrate complex. The results show that direct 'driving' motions of proteins are not necessary to explain experimental observations, and show that enzyme reactivity can be understood and accounted for in the framework of transition state theory.
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50
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Guan Y, Yang B. Kinetics for the hydrogen-abstraction of CH4 with NO2. J Comput Chem 2012; 33:1870-9. [DOI: 10.1002/jcc.23020] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2012] [Revised: 03/26/2012] [Accepted: 04/30/2012] [Indexed: 11/12/2022]
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