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Liu JZ, Jia CS. Prediction of vibrational energy levels for the CO molecule and 7Li2 dimer. Chem Phys Lett 2022. [DOI: 10.1016/j.cplett.2022.139791] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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2
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Nakatsuji H, Nakashima H. Potential curves of the lower nine states of Li2 molecule: Accurate calculations with the free complement theory and the comparisons with the SAC/SAC-CI results. J Chem Phys 2022; 157:094109. [DOI: 10.1063/5.0101315] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The free-complement (FC) theory proposed for solving the Schrödinger equation of atoms and molecules highly accurately was applied to the calculations of the potential curves of the lower nine states of the Li2 molecule. The results were compared with the accurate experimental Rydberg-Klein-Rees (RKR) potential curves available. They overlap completely with each other without any shift everywhere for all the states of Li2. At all the calculated points on the seven potential curves ranging between -14.83 ~ -15.00 hartree, the average difference was only 0.0583 kcal/mol and the maximum difference was only +0.165 kcal/mol. For the vertical excitation energies from the ground state curve to the seven excited states, the differences between theory and experiment were 0.000645 eV in average and their maximum difference was -0.00720 eV. The potential properties calculated with the FC theory also agreed well with the experimental values. These results show a high potentiality of the FC theory as a highly predictive quantum chemistry theory. For comparison, as an example of the Hartree-Fock based theory popular in modern quantum chemistry, we adopted the SAC-CI theory using a highly flexible basis set. While the FC theory gave the absolute agreements with experiments, the SAC-CI potential curves compare reasonably well with experiments only after shifting-down of the SAC-CI curves by 5.727 kcal/mol. The differences of the excitation energies between SAC-CI and experiments were 0.00428 eV in average and the maximum difference was +0.10967 eV. The SAC-CI results reported in 1985 were less accurate but still reasonable.
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Affiliation(s)
- Hiroshi Nakatsuji
- Quantum Chemistry Research Institute, Quantum Chemistry Research Institute, Japan
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3
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Sheng X, Li M, Tang KT. An accurate potential model for the a 3Σ u+ state of the lithium dimer. Phys Chem Chem Phys 2022; 24:13325-13334. [PMID: 35608033 DOI: 10.1039/d2cp01490d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
An accurate Tang-Toennies (TT) model potential is introduced to describe the interatomic potential of the lithium dimer in the a3Σu+ state. With only one well-known parameter, the ionization energy, the new model potential compares favorably with the experimentally fitted Morse/Long-range (MLR) potential of Dattani and Le Roy [J. Mol. Spectrosc., 2011, 268, 199] and is in excellent agreement with the state-of-the-art ab initio potential of Lesiuk et al. [Phys. Rev. A, 2020, 102, 062806]. With the known dispersion coefficients and the ionization energy, the new potential requires only two experimental parameters, namely the depth of the potential well De and its location Re. The new potential can be extended to the region of zero separation by the united atom limit.
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Affiliation(s)
- Xiaowei Sheng
- Anhui Province Key Laboratory of Optoelectric Materials Science and Technology, Department of Physics, Anhui Normal University, Anhui, Wuhu 241000, China
| | - Mengyuan Li
- Anhui Province Key Laboratory of Optoelectric Materials Science and Technology, Department of Physics, Anhui Normal University, Anhui, Wuhu 241000, China
| | - K T Tang
- Department of Physics, Pacific Lutheran University, Tacoma, Washington, 98447, USA.
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4
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Eyube E. Reparametrised Pöschl–Teller oscillator and analytical molar entropy equation for diatomic molecules. Mol Phys 2022. [DOI: 10.1080/00268976.2022.2037774] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Affiliation(s)
- E.S. Eyube
- Department of Physics, Faculty of Physical Sciences, Modibbo Adama University, Yola, Nigeria
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5
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Onate CA, Akanbi TA, Okon IB. Ro-vibrational energies of cesium dimer and lithium dimer with molecular attractive potential. Sci Rep 2021; 11:6198. [PMID: 33737625 PMCID: PMC7973739 DOI: 10.1038/s41598-021-85761-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2021] [Accepted: 03/05/2021] [Indexed: 11/23/2022] Open
Abstract
An approximate solution of the Schrӧdinger equation for a molecular attractive potential was obtained using the parametric Nikiforov–Uvarov method. The energy equation and the corresponding radial wave functions were calculated. The effects of the potential parameters on the energy eigenvalues were examined. The thermal properties under the molecular attractive potential were calculated and the behaviour of the thermal properties with the maximum quantum state (λ) and the temperature parameter (β) respectively, were studied. Using the molecular spectroscopic parameters, the Rydberg–Klein–Rees (RKR) of cesium dimer and lithium dimer were both obtained and compared with the experimental values. The RKR values of both cesium dimer and lithium dimer calculated aligned with the observed values. The deviation and average deviation of the RKR for each molecule were also calculated.
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Affiliation(s)
- C A Onate
- Department of Physical Sciences, Landmark University, Omu-Aran, Nigeria.
| | - T A Akanbi
- Department of Physical Sciences, Landmark University, Omu-Aran, Nigeria
| | - I B Okon
- Theoretical Physics Group, Department of Physics, University of Uyo, Uyo, Nigeria
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6
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Kendrick BK, Li H, Li M, Kotochigova S, Croft JFE, Balakrishnan N. Non-adiabatic quantum interference in the ultracold Li + LiNa → Li 2 + Na reaction. Phys Chem Chem Phys 2021; 23:5096-5112. [PMID: 33576359 DOI: 10.1039/d0cp05499b] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Electronically non-adiabatic effects play an important role in many chemical reactions. However, how these effects manifest in cold and ultracold chemistry remains largely unexplored. Here for the first time we present from first principles the non-adiabatic quantum dynamics of the reactive scattering between ultracold alkali-metal LiNa molecules and Li atoms. We show that non-adiabatic dynamics induces quantum interference effects that dramatically alter the ultracold rotationally resolved reaction rate coefficients. The interference effect arises from the conical intersection between the ground and an excited electronic state that is energetically accessible even for ultracold collisions. These unique interference effects might be exploited for quantum control applications such as a quantum molecular switch. The non-adiabatic dynamics are based on full-dimensional ab initio potential energy surfaces for the two electronic states that includes the non-adiabatic couplings and an accurate treatment of the long-range interactions. A statistical analysis of rotational populations of the Li2 product reveals a Poisson distribution implying the underlying classical dynamics are chaotic. The Poisson distribution is robust and amenable to experimental verification and appears to be a universal property of ultracold reactions involving alkali metal dimers.
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Affiliation(s)
- Brian K Kendrick
- Theoretical Division (T-1, MS B221), Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA.
| | - Hui Li
- Department of Physics, Temple University, Philadelphia, PA 19122, USA
| | - Ming Li
- Department of Physics, Temple University, Philadelphia, PA 19122, USA
| | | | - James F E Croft
- Dodd-Walls Centre for Photonic and Quantum Technologies, Dunedin 9054, New Zealand and Department of Physics, University of Otago, Dunedin 9054, New Zealand
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7
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Pingak RK, Johannes AZ, Ngara ZS, Bukit M, Nitti F, Tambaru D, Ndii MZ. Accuracy of Morse and Morse-like oscillators for diatomic molecular interaction: A comparative study. RESULTS IN CHEMISTRY 2021. [DOI: 10.1016/j.rechem.2021.100204] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022] Open
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8
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Hulet RG, Nguyen JHV, Senaratne R. Methods for preparing quantum gases of lithium. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2020; 91:011101. [PMID: 32012609 DOI: 10.1063/1.5131023] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/08/2019] [Accepted: 12/24/2019] [Indexed: 06/10/2023]
Abstract
Lithium is an important element in atomic quantum gas experiments because its interactions are highly tunable due to broad Feshbach resonances and zero-crossings and because it has two stable isotopes: 6Li, a fermion, and 7Li, a boson. Although lithium has special value for these reasons, it also presents experimental challenges. In this article, we review some of the methods that have been developed or adapted to confront these challenges, including beam and vapor sources, Zeeman slowers, sub-Doppler laser cooling, laser sources at 671 nm, and all-optical methods for trapping and cooling. Additionally, we provide spectral diagrams of both 6Li and 7Li and present plots of Feshbach resonances for both isotopes.
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Affiliation(s)
- Randall G Hulet
- Department of Physics and Astronomy, Rice University, Houston, Texas 77005, USA
| | - Jason H V Nguyen
- Department of Physics and Astronomy, Rice University, Houston, Texas 77005, USA
| | - Ruwan Senaratne
- Department of Physics and Astronomy, Rice University, Houston, Texas 77005, USA
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9
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Analytical calculations of thermodynamic functions of lithium dimer using modified Tietz and Badawi-Bessis-Bessis potentials. COMPUT THEOR CHEM 2019. [DOI: 10.1016/j.comptc.2019.03.019] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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10
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11
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Lau JA, Toennies JP, Tang KT. An accurate potential model for the a 3Σ u+ state of the alkali dimers Na 2, K 2, Rb 2, and Cs 2. J Chem Phys 2016; 145:194308. [PMID: 27875886 DOI: 10.1063/1.4967333] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
A modified semi-empirical Tang-Toennies potential model is used to describe the a3Σu+ potentials of the alkali dimers. These potentials are currently of interest in connection with the laser manipulation of the ultracold alkali gases. The fully analytical model is based on three experimental parameters, the well depth De, well location Re, and the harmonic vibrational frequency ωe of which the latter is only slightly optimized within the range of the literature values. Comparison with the latest spectroscopic data shows good agreement for Na2, K2, Rb2, and Cs2, comparable to that found with published potential models with up to 55 parameters. The differences between the reduced potential of Li2 and the conformal reduced potentials of the heavier dimers are analyzed together with why the model describes Li2 less accurately. The new model potential provides a test of the principle of corresponding states and an excellent first order approximation for further optimization to improve the fits to the spectroscopic data and describe the scattering lengths and Feshbach resonances at ultra-low temperatures.
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Affiliation(s)
- Jascha A Lau
- Max Planck Institute for Dynamics and Self-Organization, Am Fassberg 17, 37077 Goettingen, Germany
| | - J Peter Toennies
- Max Planck Institute for Dynamics and Self-Organization, Am Fassberg 17, 37077 Goettingen, Germany
| | - K T Tang
- Department of Physics, Pacific Lutheran University, Tacoma, Washington 98447, USA
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12
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Affiliation(s)
- Hilmi Yanar
- Department of Physics, Faculty of Arts and Science, Mersin University, Mersin, 33143, Turkey
| | - Oktay Aydoğdu
- Department of Physics, Faculty of Arts and Science, Mersin University, Mersin, 33143, Turkey
| | - Mustafa Saltı
- Department of Physics, Faculty of Arts and Science, Mersin University, Mersin, 33143, Turkey
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13
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Haritan I, Gilary I, Amitay Z, Moiseyev N. Characteristic footprints of an exceptional point in the dynamics of Li dimer under a laser field. J Chem Phys 2015; 143:154308. [PMID: 26493908 DOI: 10.1063/1.4931774] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Non-hermitian quantum mechanics is a formalism that excels in describing time-dependent states such as resonances. As one, it opens up a window to explore new and undiscovered phenomena. Under this formalism coalescence of two eigenstates and a deficient spectrum are a possible situation. These situations are unique and can occur solely in specific conditions known as Exceptional Points (EPs). An EP holds unique characteristics. One of which is a switch-like behavior: upon adiabatically changing the conditions in a closed loop around the EP, the population of one resonance can be transferred completely to another resonance. The phenomenon was not experimentally observed in an atomic or molecular system so far, although experiments involving nonlinear PT symmetry optics and microwave cavities have already indicated its existence. In this work, we demonstrate and confirm that the switch-like behavior exists in the spectrum of a lithium dimer taking into account both the rotations and the vibrations of the system. Moreover, a footprint of the EP is also shown to exist in the photo-association process of the lithium dimer. In this process, the EP's resonances serve as the mean to associate two free lithium atoms into a dimer. Based on this, we suggest a corresponding experiment to demonstrate for the first time the EP phenomenon in a molecular system.
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Affiliation(s)
- Idan Haritan
- Schulich Faculty of Chemistry, Technion-Israel Institute of Technology, Haifa 32000, Israel
| | - Ido Gilary
- Schulich Faculty of Chemistry, Technion-Israel Institute of Technology, Haifa 32000, Israel
| | - Zohar Amitay
- Schulich Faculty of Chemistry, Technion-Israel Institute of Technology, Haifa 32000, Israel
| | - Nimrod Moiseyev
- Schulich Faculty of Chemistry, Technion-Israel Institute of Technology, Haifa 32000, Israel
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14
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Thonhauser T, Zuluaga S, Arter CA, Berland K, Schröder E, Hyldgaard P. Spin Signature of Nonlocal Correlation Binding in Metal-Organic Frameworks. PHYSICAL REVIEW LETTERS 2015; 115:136402. [PMID: 26451571 DOI: 10.1103/physrevlett.115.136402] [Citation(s) in RCA: 105] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/22/2015] [Indexed: 06/05/2023]
Abstract
We develop a proper nonempirical spin-density formalism for the van der Waals density functional (vdW-DF) method. We show that this generalization, termed svdW-DF, is firmly rooted in the single-particle nature of exchange and we test it on a range of spin systems. We investigate in detail the role of spin in the nonlocal correlation driven adsorption of H_{2} and CO_{2} in the linear magnets Mn-MOF74, Fe-MOF74, Co-MOF74, and Ni-MOF74. In all cases, we find that spin plays a significant role during the adsorption process despite the general weakness of the molecular-magnetic responses. The case of CO_{2} adsorption in Ni-MOF74 is particularly interesting, as the inclusion of spin effects results in an increased attraction, opposite to what the diamagnetic nature of CO_{2} would suggest. We explain this counterintuitive result, tracking the behavior to a coincidental hybridization of the O p states with the Ni d states in the down-spin channel. More generally, by providing insight on nonlocal correlation in concert with spin effects, our nonempirical svdW-DF method opens the door for a deeper understanding of weak nonlocal magnetic interactions.
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Affiliation(s)
- T Thonhauser
- Department of Physics, Wake Forest University, Winston-Salem, North Carolina 27106, USA
| | - S Zuluaga
- Department of Physics, Wake Forest University, Winston-Salem, North Carolina 27106, USA
| | - C A Arter
- Department of Physics, Wake Forest University, Winston-Salem, North Carolina 27106, USA
| | - K Berland
- Microtechnology and Nanoscience, MC2, Chalmers University of Technology, SE-412 96 Göteborg, Sweden
- Centre for Materials Science and Nanotechnology (SMN), University of Oslo, 0316 Oslo, Norway
| | - E Schröder
- Microtechnology and Nanoscience, MC2, Chalmers University of Technology, SE-412 96 Göteborg, Sweden
| | - P Hyldgaard
- Microtechnology and Nanoscience, MC2, Chalmers University of Technology, SE-412 96 Göteborg, Sweden
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16
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Sun W, Zhang Y, Fan Q, Feng H, Fu J, Li H, Ma J, Xiao L, Jia S. Hidden physics in molecular rovibrational spectrum. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2014; 132:32-37. [PMID: 24854134 DOI: 10.1016/j.saa.2014.04.137] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/20/2014] [Revised: 04/02/2014] [Accepted: 04/13/2014] [Indexed: 06/03/2023]
Abstract
An algebraic method for rotational energies (AMr) is proposed to unearth the rotational spectrum {ɛJ} and the rovibrational interaction energies ευJint that are hidden in the rovibrational energies EυJ. The applications to the excited electronic state a3Σu+ of 7Li2 and the ground state X1Σ+ of NaF molecules show that: (1) the rotational energies ɛJ of the lighter 7Li2 molecule have better accuracies than the widely used rigid rotor rotational energies εJrr particularly for the lowest two rotational states, while the rigid rotor model produces satisfied rotational energies for the heavier NaF molecule and (2) the attractive rovibrational interaction energies ευJint stabilize a molecular rovibrational system.
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Affiliation(s)
- Weiguo Sun
- School of Physics and Chemistry, Research Center for Advanced Computation, Xihua University, Chengdu, Sichuan 610039, PR China; Institute of Atomic and Molecular Physics, Sichuan University, Chengdu, Sichuan 610065, PR China.
| | - Yi Zhang
- School of Physics and Chemistry, Research Center for Advanced Computation, Xihua University, Chengdu, Sichuan 610039, PR China; School of Physics, Sichuan University, Chengdu, Sichuan 610065, PR China
| | - Qunchao Fan
- School of Physics and Chemistry, Research Center for Advanced Computation, Xihua University, Chengdu, Sichuan 610039, PR China
| | - Hao Feng
- School of Physics and Chemistry, Research Center for Advanced Computation, Xihua University, Chengdu, Sichuan 610039, PR China
| | - Jia Fu
- School of Physics and Chemistry, Research Center for Advanced Computation, Xihua University, Chengdu, Sichuan 610039, PR China; School of Physics, Sichuan University, Chengdu, Sichuan 610065, PR China
| | - Huidong Li
- School of Physics and Chemistry, Research Center for Advanced Computation, Xihua University, Chengdu, Sichuan 610039, PR China; Institute of Atomic and Molecular Physics, Sichuan University, Chengdu, Sichuan 610065, PR China
| | - Jie Ma
- State Key Laboratory of Quantum Optics and Quantum Optics Devices, Laser Spectroscopy Laboratory, Shanxi University, Taiyuan 030006, PR China
| | - Liantuan Xiao
- State Key Laboratory of Quantum Optics and Quantum Optics Devices, Laser Spectroscopy Laboratory, Shanxi University, Taiyuan 030006, PR China
| | - Suotang Jia
- State Key Laboratory of Quantum Optics and Quantum Optics Devices, Laser Spectroscopy Laboratory, Shanxi University, Taiyuan 030006, PR China
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Musiał M, Kucharski SA. First Principle Calculations of the Potential Energy Curves for Electronic States of the Lithium Dimer. J Chem Theory Comput 2014; 10:1200-11. [DOI: 10.1021/ct401076e] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Monika Musiał
- Institute of Chemistry, University of Silesia, Szkolna 9, 40-006 Katowice, Poland
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18
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Zürn G, Lompe T, Wenz AN, Jochim S, Julienne PS, Hutson JM. Precise characterization of 6Li Feshbach resonances using trap-sideband-resolved RF spectroscopy of weakly bound molecules. PHYSICAL REVIEW LETTERS 2013; 110:135301. [PMID: 23581332 DOI: 10.1103/physrevlett.110.135301] [Citation(s) in RCA: 76] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/06/2012] [Indexed: 06/02/2023]
Abstract
We perform radio-frequency dissociation spectroscopy of weakly bound 6Li2 Feshbach molecules using low-density samples of about 30 molecules in an optical dipole trap. Combined with a high magnetic field stability, this allows us to resolve the discrete trap levels in the radio-frequency dissociation spectra. This novel technique allows the binding energy of Feshbach molecules to be determined with unprecedented precision. We use these measurements as an input for a fit to the 6Li scattering potential using coupled-channel calculations. From this new potential, we determine the pole positions of the broad 6Li Feshbach resonances with an accuracy better than 7×10(-4) of the resonance widths. This eliminates the dominant uncertainty for current precision measurements of the equation of state of strongly interacting Fermi gases. As an important consequence, our results imply a corrected value for the Bertsch parameter ξ measured by Ku et al. [Science 335, 563 (2012)], which is ξ=0.370(5)(8).
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Affiliation(s)
- G Zürn
- Physikalisches Institut, Ruprecht-Karls-Universität Heidelberg, 69120 Heidelberg, Germany
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19
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Fan Q, Sun W. Studies on the full vibrational spectra and molecular dissociation energies for some diatomic electronic states. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2009; 72:298-305. [PMID: 19022701 DOI: 10.1016/j.saa.2008.09.025] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/04/2008] [Revised: 08/05/2008] [Accepted: 09/26/2008] [Indexed: 05/27/2023]
Abstract
A parameter-free formula is suggested to evaluate the molecular dissociation energy of a stable diatomic electronic system. The full vibrational spectra (E(upsilon)(AM)) and theoretical dissociation energies D(e)(AM) are studied using the algebraic method (AM) and the suggested analytical formula for some electronic states of Li(2), K(2), Na(2), and Sr(2) molecules which have regular (Morse-like) potentials. Both the (E(upsilon)(AM)) and the calculated D(e)(AM) agree excellently with known experimental values for each electronic state.
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Affiliation(s)
- Qunchao Fan
- Institute of Physics, Sichuan University, Chengdu, Sichuan 610065, People's Republic of China
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Cvitas MT, Soldán P, Hutson JM, Honvault P, Launay JM. Interactions and dynamics in Li+Li2 ultracold collisions. J Chem Phys 2007; 127:074302. [PMID: 17718608 DOI: 10.1063/1.2752162] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
A potential energy surface for the lowest quartet electronic state ((4)A(')) of lithium trimer is developed and used to study spin-polarized Li+Li(2) collisions at ultralow kinetic energies. The potential energy surface allows barrierless atom exchange reactions. Elastic and inelastic cross sections are calculated for collisions involving a variety of rovibrational states of Li(2). Inelastic collisions are responsible for trap loss in molecule production experiments. Isotope effects and the sensitivity of the results to details of the potential energy surface are investigated. It is found that for vibrationally excited states, the cross sections are only quite weakly dependent on details of the potential energy surface.
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Affiliation(s)
- Marko T Cvitas
- Department of Chemistry, University of Durham, South Road, Durham DH1 3LE, United Kingdom
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21
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Salami H, Ross AJ, Crozet P, Jastrzebski W, Kowalczyk P, Le Roy RJ. A full analytic potential energy curve for the a 3 Sigma+ state of KLi from a limited vibrational data set. J Chem Phys 2007; 126:194313. [PMID: 17523810 DOI: 10.1063/1.2734973] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Fourier transform spectra of near-infrared laser-induced fluorescence in (39)K(6)Li show transitions to high vibrational levels of both the X (1)Sigma(+) and a (3)Sigma(+) electronic states. These include 147 transitions into six vibrational levels of the a (3)Sigma(+) state, which lie between 7 and 88 cm(-1) below the dissociation asymptote. Unfortunately, their energies span less than 30% of the well depth. However, fitting those data to eigenvalues of analytical model potential functions whose outer limbs incorporate the theoretically predicted long-range form, V(R) approximately D-C(6)R(6)-C(8)R(8), yields complete, plausible potential curves for this state. The best fits converge to remarkably similar solutions which indicate that D(e)=287(+/-4) cm(-1) and R(e)=4.99(+/-0.09) A for the a (3)Sigma(+) state of KLi, with omega(e)=47.3(+/-1.4) and 44.2(+/-1.5) cm(-1) for (39)K(6)Li and (39)K(7)Li, respectively. Properties of the resulting potential are similar to those of a published ab initio potential and are consistent with those of the analogous states of Li(2), K(2), Na(2), and NaK.
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Affiliation(s)
- H Salami
- Laboratoire de Spectrométrie Ionique et Moléculaire, Université Lyon 1 and CNRS (Unité Mixte de Recherche 5579), 43 Boulevard du 11 Novembre 1918, F-69622 Villeurbanne, France
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22
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Ren W, Sun W. Accurate studies on the full vibrational energy spectra and molecular dissociation energies for some electronic states of the Li 2molecule. Mol Phys 2007. [DOI: 10.1080/00268970701283799] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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23
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Miles RD, Morgus L, Kashinski DO, Huennekens J, Hickman AP. Nonadiabatic coupling in the 3 3Pi and 4 3Pi states of NaK. J Chem Phys 2006; 125:154304. [PMID: 17059252 DOI: 10.1063/1.2348635] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
The excited 3 (3)Pi and 4 (3)Pi electronic states of the NaK molecule exhibit an avoided crossing, leading to the anomalous behavior of many features of the rovibrational energy levels belonging to each state. A joint experimental and theoretical investigation of these states has been carried out. Experimental measurements of the vibrational, rotational, and hyperfine structure of numerous levels of the 3 (3)Pi state were recently obtained using the Doppler-free, perturbation-facilitated optical-optical double resonance technique. Additional measurements for the 4 (3)Pi state as well as bound-free emission spectra from selected 3 (3)Pi, 4 (3)Pi, and mixed 3 (3)Pi to approximately 4 (3)Pi rovibrational levels are reported here. A model is also presented for calculating the mixed rovibrational level energies of the coupled 3 (3)Pi-4 (3)Pi system, starting from a 2x2 diabatic electronic Hamiltonian. The 3 (3)Pi and 4 (3)Pi potential curves and the coupling between them are simultaneously adjusted to fit the observed rovibrational levels of both states. The energy levels of the potential curves determined by the fit are in excellent agreement with experiment. The nonadiabatic coupling is sufficiently strong to cause an overall shift of 2-3 cm(-1) for many rovibrational levels as well as somewhat larger shifts for certain pairs of 3 (3)Pi to approximately 4 (3)Pi levels that would otherwise be very close together.
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Affiliation(s)
- R D Miles
- Department of Physics, Lehigh University, Bethlehem, Pennsylvania 18015, USA
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Minaev B. Ab initio study of low-lying triplet states of the lithium dimer. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2005; 62:790-9. [PMID: 16099708 DOI: 10.1016/j.saa.2005.03.006] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/03/2005] [Revised: 03/02/2005] [Accepted: 03/02/2005] [Indexed: 05/04/2023]
Abstract
Observation of Bose-Einstein condensation in Li27 initiated the interest in the scattering length of two ground state lithium atoms when they approach each other as a radical pair triplet aSigmau+3 state. But some properties of this state are still unknown. In present work, a number of low-lying triplet states of lithium molecule are calculated by multi-configuration self-consistent field (MCSCF) and response techniques with account of spin-orbit coupling, spin-spin coupling and some other magnetic perturbations. The singlet-triplet transition probabilities to the ground state are also presented. Most results are connected with the weakly bound lowest triplet a3Sigmau+ state, whose radiative lifetime and spin-splitting are unknown so far in spite of its great importance in Bose-Einstein condensation. Calculations indicate that this state has a very small spin-splitting, lambdass=-0.01 cm-1, which is negligible in comparison with the line-width in experimental Fourier transform spectra published so far. Similar splitting is obtained for the upper state of the 1(3)Sigmag+--a3Sigmau+ transition. This is in agreement with experimental rovibronic analysis of the 1(3)Sigmag+--a3Sigmau+ band system in which the triplet structure was not resolved. The radiative lifetime of the a3Sigmau+ state is predicted to exceed 10 h.
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Affiliation(s)
- Boris Minaev
- State University of Technology, Cherkassy 18006, Ukraine.
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25
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Wilkins AD, Morgus L, Hernandez-Guzman J, Huennekens J, Hickman AP. The NaK 1 1,3delta states: theoretical and experimental studies of fine and hyperfine structure of rovibrational levels near the dissociation limit. J Chem Phys 2005; 123:124306. [PMID: 16392481 DOI: 10.1063/1.2010471] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Earlier high-resolution spectroscopic studies of the fine and hyperfine structure of rovibrational levels of the 1 3delta state of NaK have been extended to include high lying rovibrational levels with v < or = 59, of which the highest levels lie within approximately 4 cm(-1) of the dissociation limit. A potential curve is determined using the inverted perturbation approximation method that reproduces these levels to an accuracy of approximately 0.026 cm(-1). For the largest values of v, the outer turning points occur near R approximately 12.7 angstroms, which is sufficiently large to permit the estimation of the C6 coefficient for this state. The fine and hyperfine structure of the 1 3delta rovibrational levels has been fit using the matrix diagonalization method that has been applied to other states of NaK, leading to values of the spin-orbit coupling constant A(v) and the Fermi contact constant b(F). New values determined for v < or = 33 are consistent with values determined by a simpler method and reported earlier. The measured fine and hyperfine structure for v in the range 44 < or = v < or = 49 exhibits anomalous behavior whose origin is believed to be the mixing between the 1 3delta and 1 1delta states. The matrix diagonalization method has been extended to treat this interaction, and the results provide an accurate representation of the complicated patterns that arise. The analysis leads to accurate values for A(v) and b(F) for all values of v < or = 49. For higher v (50 < or = v < or = 59), several rovibrational levels have been assigned, but the pattern of fine and hyperfine structure is difficult to interpret. Some of the observed features may arise from effects not included in the current model.
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Affiliation(s)
- A D Wilkins
- Department of Physics, Lehigh University, Bethlehem, Pennsylvania 18015, USA
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26
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Sun * W, Ren W, Hou S, Feng H. Studies on full vibrational spectra and dissociation energies of some diatomic molecular electronic states using algebraic approaches. Mol Phys 2005. [DOI: 10.1080/01449290500102185] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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27
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Morgus L, Burns P, Miles RD, Wilkins AD, Ogba U, Hickman AP, Huennekens J. Experimental study of the NaK 3 3Pi double minimum state. J Chem Phys 2005; 122:144313. [PMID: 15847528 DOI: 10.1063/1.1875132] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
We have used the Doppler-free, perturbation-facilitated optical-optical double-resonance technique to investigate the vibrational, rotational, and hyperfine structure of the 3 (3)Pi double minimum state of NaK. Since this electronic state arises from an avoided crossing with the nearby 4 (3)Pi state, we observe striking patterns in the data that provide a sensitive probe of the electronic wave function in the various regions of the double well potential. A single-mode cw dye laser excites 2(A) (1)Sigma(+)(v(A),J) approximately 1(b) (3)Pi(Omega=0)(v(b),J) mixed singlet-triplet "window" levels from thermally populated rovibrational ground state levels, 1(X) (1)Sigma(+)(v(X),J+/-1). Further excitation by a single-mode cw Ti:sapphire laser selects various 3 (3)Pi(0)(v(Pi),J(Pi)) rovibrational levels, which are detected by observing direct 3 (3)Pi(0)-->1(a) (3)Sigma(+) fluorescence in the green spectral region. Using the inverse perturbation approximation method, we have determined a 3 (3)Pi(0) potential curve that reproduces the measured energies to approximately 0.24 cm(-1). In addition, the hyperfine and spin-orbit constants, b(F) and A(v), have been determined for each region of the potential curve.
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Affiliation(s)
- L Morgus
- Department of Physics, Lehigh University, Bethlehem, Pennsylvania 18015, USA
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28
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29
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Burns P, Sibbach-Morgus L, Wilkins AD, Halpern F, Clarke L, Miles RD, Li L, Hickman AP, Huennekens J. The 4 3Σ+ state of NaK: Potential energy curve and hyperfine structure. J Chem Phys 2003. [DOI: 10.1063/1.1590638] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
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30
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Colavecchia FD, Burke JP, Stevens WJ, Salazar MR, Parker GA, T Pack R. The potential energy surface for spin-aligned Li3(1 4A′) and the potential energy curve for spin-aligned Li2(a 3Σu+). J Chem Phys 2003. [DOI: 10.1063/1.1555124] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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31
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Tellinghuisen J. On the efficient representation of comprehensive, precise spectroscopic data sets: The A state of I2. J Chem Phys 2003. [DOI: 10.1063/1.1539849] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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32
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Halls M, Schlegel H, DeWitt M, Drake G. Ab initio calculation of the Σ interaction potential and vibrational levels of. Chem Phys Lett 2001. [DOI: 10.1016/s0009-2614(01)00403-1] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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33
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Huennekens J, Prodan I, Marks A, Sibbach L, Galle E, Morgus T, Li L. Experimental studies of the NaK 1 3Δ state. J Chem Phys 2000. [DOI: 10.1063/1.1310609] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
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34
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Dai X, Clevenger JO, Liu Y, Song M, Shang J, Chen D, Field RW, Li L. The 2(3)Delta(g) State of (7)Li(2). JOURNAL OF MOLECULAR SPECTROSCOPY 2000; 200:120-122. [PMID: 10662582 DOI: 10.1006/jmsp.1999.8033] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Using pulsed perturbation-facilitated optical-optical double resonance (PFOODR) spectroscopy, the 2(3)Delta(g) state of (7)Li(2) (electronic configuration (varsigma(g)2s) (4ddelta(g)), effective principal quantum number n* = 4.101) has been observed and assigned. Molecular constants and a RKR potential energy curve were obtained. The major molecular constants are Copyright 2000 Academic Press.
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Affiliation(s)
- X Dai
- Department of Physics and Center of Atomic and Molecular Sciences, Tsinghua University, Beijing, 100084, China
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