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Morita M, Kendrick BK, Kłos J, Kotochigova S, Brumer P, Tscherbul TV. Signatures of Non-universal Quantum Dynamics of Ultracold Chemical Reactions of Polar Alkali Dimer Molecules with Alkali Metal Atoms: Li( 2S) + NaLi( a3Σ +) → Na( 2S) + Li 2( a3Σ u+). J Phys Chem Lett 2023; 14:3413-3421. [PMID: 37001115 DOI: 10.1021/acs.jpclett.3c00159] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/19/2023]
Abstract
Ultracold chemical reactions of weakly bound triplet-state alkali metal dimer molecules have recently attracted much experimental interest. We perform rigorous quantum scattering calculations with a new ab initio potential energy surface to explore the chemical reaction of spin-polarized NaLi(a3Σ+) and Li(2S) to form Li2(a3Σu+) and Na(2S). The reaction is exothermic and proceeds readily at ultralow temperatures. Significantly, we observe strong sensitivity of the total reaction rate to small variations of the three-body part of the Li2Na interaction at short range, which we attribute to a relatively small number of open Li2(a3Σu+) product channels populated in the reaction. This provides the first signature of highly non-universal dynamics seen in rigorous quantum reactive scattering calculations of an ultracold exothermic insertion reaction involving a polar alkali dimer molecule, opening up the possibility of probing microscopic interactions in atom+molecule collision complexes via ultracold reactive scattering experiments.
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Affiliation(s)
- Masato Morita
- Chemical Physics Theory Group, Department of Chemistry, and Center for Quantum Information and Quantum Control, University of Toronto, Toronto, Ontario M5S 3H6, Canada
| | - Brian K Kendrick
- Theoretical Division (T-1, MS B221), Los Alamos National Laboratory, Los Alamos, New Mexico 87545, United States
| | - Jacek Kłos
- Joint Quantum Institute, University of Maryland, College Park, Maryland 20742, United States
- Department of Physics, Temple University, Philadelphia, Pennsylvania 19122, United States
| | - Svetlana Kotochigova
- Department of Physics, Temple University, Philadelphia, Pennsylvania 19122, United States
| | - Paul Brumer
- Chemical Physics Theory Group, Department of Chemistry, and Center for Quantum Information and Quantum Control, University of Toronto, Toronto, Ontario M5S 3H6, Canada
| | - Timur V Tscherbul
- Department of Physics, University of Nevada, Reno, Nevada 89557, United States
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2
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Mukherjee N. Quantum-Controlled Collisions of H 2 Molecules. J Phys Chem A 2023; 127:418-438. [PMID: 36602238 DOI: 10.1021/acs.jpca.2c06808] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
The amount of information that can be obtained from a scattering experiment depends upon the precision with which the quantum states are defined in the incoming channel. By precisely defining the incoming states and measuring the outgoing states in a scattering experiment, we set up the boundary condition for experimentally solving the Schrödinger equation. In this Perspective we discuss cold inelastic scattering experiments using the most theoretically tractable H2 and its isotopologues as the target. We prepare the target in a precisely defined rovibrational (v, j, m) quantum state using a special coherent optical technique called the Stark-induced adiabatic Raman passage (SARP). v and j represent the quantum numbers of the vibrational and rotational energy levels, and m refers to the projection of the rotational angular momentum vector j on a suitable quantization axis in the laboratory frame. Selection of the m quantum numbers defines the alignment of the molecular frame, which is necessary to probe the anisotropic interactions. For us to achieve the collision temperature in the range of a few degrees Kelvin, we co-expand the colliding partners in a mixed supersonic beam that is collimated to define a direction for the collision velocity. When the bond axis is aligned with respect to a well-defined collision velocity, SARP achieves stereodynamic control at the quantum scale. Through various examples of rotationally inelastic cold scattering experiments, we show how SARP coherently controls the dynamics of anisotropic interactions by preparing quantum superpositions of the orientational m states within a single rovibrational (v, j) energy state. A partial wave analysis, which has been developed for the cold scattering experiments, shows dominance of a resonant orbital that leaves its mark in the scattering angular distribution. These highly controlled cold collision experiments at the single partial wave limit allow the most direct comparison with the results of theoretical computations, necessary for accurate modeling of the molecular interaction potential.
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Affiliation(s)
- Nandini Mukherjee
- Department of Chemistry, Stanford University, Stanford, California94305, United States
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3
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Mao Y, Buren B, Yang Z, Chen M. Time-dependent wave packet dynamics study of the resonances in the H + LiH +( v = 0, j = 0) → Li + + H 2 reaction at low collision energies. Phys Chem Chem Phys 2022; 24:15532-15539. [PMID: 35713276 DOI: 10.1039/d1cp05601h] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The depletion process of LiH+ by H collision plays an important role in the evolution of the early universe and astrophysical processes, including the eventual charge-states, abundances of atomic and molecular species and ensuing astrochemistry. Here, a quantum dynamics study on the H + LiH+(v = 0, j = 0) → Li+ + H2 reaction is performed at the low collision energy range from 0.1 meV to 10 meV using the time-dependent wave packet method. A Feshbach resonance peak is observed near 0.8 meV collision energy on the total reaction probability curves. This resonance originates from the coupling with the v = 0, j = 1 energy level of the reactant LiH+, and it is dominated by the contributions of J = 0-4 partial waves. Another partial wave resonance is also found on the total integral cross section at 1.2 meV, which is closely connected to the opening of the J = 7 partial wave. The opening of the J = 7 partial wave generates a notable forward scattering peak, and the Feshbach resonance can promote both the forward and backward scatterings. Moreover, the total and product vibrational state-resolved rate coefficients for the temperature range of 1-100 K are also reported.
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Affiliation(s)
- Ye Mao
- Key Laboratory of Materials Modification by Laser, Electron, and Ion Beams (Ministry of Education), School of Physics, Dalian University of Technology, Dalian 116024, P. R. China.
| | - Bayaer Buren
- Key Laboratory of Materials Modification by Laser, Electron, and Ion Beams (Ministry of Education), School of Physics, Dalian University of Technology, Dalian 116024, P. R. China.
| | - Zijiang Yang
- Key Laboratory of Materials Modification by Laser, Electron, and Ion Beams (Ministry of Education), School of Physics, Dalian University of Technology, Dalian 116024, P. R. China.
| | - Maodu Chen
- Key Laboratory of Materials Modification by Laser, Electron, and Ion Beams (Ministry of Education), School of Physics, Dalian University of Technology, Dalian 116024, P. R. China.
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Perreault WE, Zhou H, Mukherjee N, Zare RN. Coherent Preparation of Highly Vibrating and Rotating D 2 Molecules. J Phys Chem Lett 2022; 13:4682-4687. [PMID: 35605182 DOI: 10.1021/acs.jpclett.2c01209] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Highly vibrationally and rotationally excited hydrogen molecules are of immense interest for understanding and modeling the physics and chemistry of the cold interstellar medium. Using a sequence of two Stark-induced adiabatic Raman passages, we demonstrate the preparation of rotationally excited D2 molecules in the fourth excited vibrational level within its ground electronic state. The nearly complete population transfer to the target state is confirmed by observing both the threshold behavior as a function of the laser power and the depletion of the intermediate level. The vibrational excitation reported here opens new possibilities in the study of the much debated four-center reaction between a pair of hydrogen molecules. Additionally, these rovibrationally excited molecules could be potentially used to generate the high-intensity D- ion beams considered essential for D-T thermonuclear fusion by enhancing the cross section for dissociative electron attachment by 5 orders of magnitude compared to that of the ground state.
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Affiliation(s)
- William E Perreault
- Department of Chemistry, Stanford University, Stanford, California 94305, United States
| | - Haowen Zhou
- Department of Chemistry, Stanford University, Stanford, California 94305, United States
| | - Nandini Mukherjee
- Department of Chemistry, Stanford University, Stanford, California 94305, United States
| | - Richard N Zare
- Department of Chemistry, Stanford University, Stanford, California 94305, United States
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De Fazio D, Aquilanti V, Cavalli S. Benchmark Quantum Kinetics at Low Temperatures toward Absolute Zero and Role of Entrance Channel Wells on Tunneling, Virtual States, and Resonances: The F + HD Reaction. J Phys Chem A 2020; 124:12-20. [PMID: 31829589 DOI: 10.1021/acs.jpca.9b08435] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
This paper reports a study of the quantum reaction dynamics and kinetics of the F + HD reaction at low and ultralow temperatures, focusing on the range from the Wigner limit up to 50 K. Close coupling time-independent quantum reactive scattering calculations for the production of HF and DF molecules have been carried out on two potential energy surfaces differing in the description of the reaction entrance channel. This case is computationally more demanding than the cases of F with H2 and D2 ( De Fazio et al. Frontiers in Chemistry 2019 , 7 , 328 ) but offers a wider phenomenology regarding the roles of quantum mechanical effects of tunneling, of virtual states, and of resonances. The results show that at the temperatures in the cold and ultracold regimes small changes in the entrance channel long-range interaction induce surprising near threshold features. The presence of a virtual state close to the reactive threshold gives rise to a marked anti-Arrhenius behavior of the rate constants below 100 mK. This effect enhances reaction rates by about 2 orders of magnitude, making them of the same order as those at room temperature and confining the onset of the Wigner regime in the microkelvin region.
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Affiliation(s)
- Dario De Fazio
- Istituto di Struttura della materia-Consiglio Nazionale delle Ricerche , 00016 Roma , Italy
| | - Vincenzo Aquilanti
- Istituto di Struttura della materia-Consiglio Nazionale delle Ricerche , 00016 Roma , Italy.,Dipartimento di Chimica, Biologia e Biotecnologie , Università di Perugia , 06123 Perugia , Italy
| | - Simonetta Cavalli
- Dipartimento di Chimica, Biologia e Biotecnologie , Università di Perugia , 06123 Perugia , Italy
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6
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Several considerations on the empirical rate formula for ion-molecule reactions and low-temperature-high-speed radical reactions. Chem Phys 2019. [DOI: 10.1016/j.chemphys.2019.04.018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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7
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De Fazio D, Aquilanti V, Cavalli S. Quantum Dynamics and Kinetics of the F + H 2 and F + D 2 Reactions at Low and Ultra-Low Temperatures. Front Chem 2019; 7:328. [PMID: 31157204 PMCID: PMC6527900 DOI: 10.3389/fchem.2019.00328] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2019] [Accepted: 04/24/2019] [Indexed: 11/29/2022] Open
Abstract
Integral cross sections and rate constants for the prototypical chemical reactions of the fluorine atom with molecular hydrogen and deuterium have been calculated over a wide interval of collision energy and temperature ranging from the sub-thermal (50 K) down to the ultra-cold regimes (0.5 mK). Rigorous close coupling time-independent quantum reactive scattering calculations have been carried out on two potential energy surfaces, differing only at long-range in the reactants' channel. The results show that tunnel, resonance and virtual state effects enhance under-barrier reactivity giving rise to pronounced deviations from the Arrhenius law as temperature is lowered. Within the ultra-cold domain (below 1 mK), the reactivity is governed by virtual state effects and by tunneling through the reaction barrier; in the cold regime (1 mK–1 K), the shape resonances in the entrance channel of the potential energy surface make the quantum tunneling contribution larger so enhancing cross sections and rate constants by about one order of magnitude; at higher temperatures (above 10 K), the tunneling pathway enhanced by the constructive interference between two Feshbach resonances trapped in the reaction exit channel competes with the thermally activated mechanism, as the energy gets closer to the reaction barrier height. The results show that at low temperatures cross sections and rate constants are extremely sensitive to small changes in the long-range intermolecular interaction in the entrance channel of the potential energy surface, as well as to isotopic substitution.
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Affiliation(s)
- Dario De Fazio
- Istituto di Struttura della Materia, Consiglio Nazionale Delle Ricerche (CNR), Rome, Italy
| | - Vincenzo Aquilanti
- Dipartimento di Chimica, Biologia e Biotecnologie, Università degli Studi di Perugia, Perugia, Italy
| | - Simonetta Cavalli
- Dipartimento di Chimica, Biologia e Biotecnologie, Università degli Studi di Perugia, Perugia, Italy
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8
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Kendrick BK. Non-adiabatic quantum reactive scattering calculations for the ultracold hydrogen exchange reaction: H + H2(v=4-8,j=0) → H + H2(v′,j′). Chem Phys 2018. [DOI: 10.1016/j.chemphys.2018.07.001] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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9
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Côté R, Simbotin I. Signature of the s-Wave Regime High above Ultralow Temperatures. PHYSICAL REVIEW LETTERS 2018; 121:173401. [PMID: 30411919 DOI: 10.1103/physrevlett.121.173401] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/15/2018] [Indexed: 06/08/2023]
Abstract
Resonant exchange is a general process playing a key role in many-body dynamics and transport phenomena, such as spin, charge, or excitation diffusion. The underlying process is described by the resonant exchange cross section. We show that the s-wave scattering, generally thought to contribute mainly in the ultracold (or Wigner) regime, dictates the overall cross section over a broad range of energies. We derive an analytical expression and explain its applicability high above the Wigner regime. In particular, we demonstrate its relationship to the classical capture (Langevin) cross section and apply it to three very different resonant processes: namely, resonant charge transfer, spin flip, and excitation exchange. This expression explains large variations for different isotopes that cannot otherwise be accounted for by the small change in mass. The s-wave signature also allows us to gain information about the Wigner regime from data obtained at much higher temperatures, which is especially advantageous for systems where the ultracold regime is not reachable.
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Affiliation(s)
- Robin Côté
- Department of Physics, U-3046, University of Connecticut, 2152 Hillside Road, U-3046 Storrs, Connecticut 06269-3046, USA
| | - Ionel Simbotin
- Department of Physics, U-3046, University of Connecticut, 2152 Hillside Road, U-3046 Storrs, Connecticut 06269-3046, USA
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10
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Accurate quantum mechanical rate coefficients for D+H2(v,j) reaction: From ultracold to thermal temperature limit. COMPUT THEOR CHEM 2017. [DOI: 10.1016/j.comptc.2016.12.032] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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11
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Kendrick BK, Hazra J, Balakrishnan N. Geometric phase effects in the ultracold H + H2reaction. J Chem Phys 2016; 145:164303. [DOI: 10.1063/1.4966037] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- B. K. Kendrick
- Theoretical Division (T-1, MS B221), Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - Jisha Hazra
- Department of Chemistry, University of Nevada, Las Vegas, Nevada 89154, USA
| | - N. Balakrishnan
- Department of Chemistry, University of Nevada, Las Vegas, Nevada 89154, 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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Simbotin I, Côté R. Jost function description of near threshold resonances for coupled-channel scattering. Chem Phys 2015. [DOI: 10.1016/j.chemphys.2015.06.009] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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14
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Kendrick BK, Hazra J, Balakrishnan N. Geometric Phase Appears in the Ultracold Hydrogen Exchange Reaction. PHYSICAL REVIEW LETTERS 2015; 115:153201. [PMID: 26550721 DOI: 10.1103/physrevlett.115.153201] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/23/2015] [Indexed: 06/05/2023]
Abstract
Quantum reactive scattering calculations for the hydrogen exchange reaction H+H_{2}(v=4,j=0)→H+H_{2}(v^{'}, j^{'}) and its isotopic analogues are reported for ultracold collision energies. Because of the unique properties associated with ultracold collisions, it is shown that the geometric phase effectively controls the reactivity. The rotationally resolved rate coefficients computed with and without the geometric phase are shown to differ by up to 4 orders of magnitude. The effect is also significant in the vibrationally resolved and total rate coefficients. The dynamical origin of the effect is discussed and the large geometric phase effect reported here might be exploited to control the reactivity through the application of external fields or by the selection of a particular nuclear spin state.
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Affiliation(s)
- B K Kendrick
- Theoretical Division (T-1, MS B221), Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - Jisha Hazra
- Department of Chemistry, University of Nevada, Las Vegas, Nevada 89154, USA
| | - N Balakrishnan
- Department of Chemistry, University of Nevada, Las Vegas, Nevada 89154, USA
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15
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Wang J, Byrd JN, Simbotin I, Côté R. Tuning ultracold chemical reactions via Rydberg-dressed interactions. PHYSICAL REVIEW LETTERS 2014; 113:025302. [PMID: 25062202 DOI: 10.1103/physrevlett.113.025302] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/07/2013] [Indexed: 06/03/2023]
Abstract
We show that ultracold chemical reactions with an activation barrier can be tuned using Rydberg-dressed interactions. Scattering in the ultracold regime is sensitive to long-range interactions, especially when weakly bound (or quasibound) states exist near the collision threshold. We investigate how, by Rydberg dressing a reactant, one enhances its polarizability and modifies the long-range van der Waals collision complex, which can alter chemical reaction rates by shifting the position of near-threshold bound states. We carry out a full quantum mechanical scattering calculation for the benchmark system H(2)+D, and show that resonances can be moved substantially and that rate coefficients at cold and ultracold temperatures can be increased by several orders of magnitude.
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Affiliation(s)
- Jia Wang
- Department of Physics, University of Connecticut, 2152 Hillside Road, Storrs, Connecticut 06269, USA
| | - Jason N Byrd
- Department of Physics, University of Connecticut, 2152 Hillside Road, Storrs, Connecticut 06269, USA and Quantum Theory Project, University of Florida, Gainesville, Florida 32611, USA
| | - Ion Simbotin
- Department of Physics, University of Connecticut, 2152 Hillside Road, Storrs, Connecticut 06269, USA
| | - R Côté
- Department of Physics, University of Connecticut, 2152 Hillside Road, Storrs, Connecticut 06269, USA and Institute for Quantum Computing, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada
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Pradhan GB, Balakrishnan N, Kendrick BK. Ultracold collisions of O(1D) and H2: The effects of H2vibrational excitation on the production of vibrationally and rotationally excited OH. J Chem Phys 2013; 138:164310. [DOI: 10.1063/1.4802476] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
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