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Szczepkowski J, Gronowski M, Grochola A, Jastrzebski W, Tomza M, Kowalczyk P. Excited Electronic States of Sr 2: Ab Initio Predictions and Experimental Observation of the 2 1Σ u+ State. J Phys Chem A 2023; 127:4473-4482. [PMID: 37192534 DOI: 10.1021/acs.jpca.3c02056] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Despite its apparently simple nature with four valence electrons, the strontium dimer constitutes a challenge for modern electronic structure theory. Here we focus on excited electronic states of Sr2, which we investigate theoretically up to 25000 cm-1 above the ground state, to guide and explain new spectroscopic measurements. In particular, we focus on potential energy curves for the 11Σu+, 21Σu+, 11Πu, 21Πu, and 11Δu states computed using several variants of ab initio coupled-cluster and configuration-interaction methods to benchmark them. In addition, a new experimental study of the excited 21Σu+ state using polarization labeling spectroscopy is presented, which extends knowledge of this state to high vibrational levels, where perturbation by higher electronic states is observed. The available experimental observations are compared with the theoretical predictions and help to assess the accuracy and limitations of employed theoretical models. The present results pave the way for future more accurate theoretical and experimental spectroscopic studies.
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Affiliation(s)
- Jacek Szczepkowski
- Institute of Physics, Polish Academy of Sciences, al. Lotników 32/46, 02-668 Warsaw, Poland
| | - Marcin Gronowski
- Institute of Theoretical Physics, Faculty of Physics, University of Warsaw, ul. Pasteura 5, 02-093 Warszawa, Poland
| | - Anna Grochola
- Institute of Physics, Polish Academy of Sciences, al. Lotników 32/46, 02-668 Warsaw, Poland
| | | | - Michał Tomza
- Institute of Theoretical Physics, Faculty of Physics, University of Warsaw, ul. Pasteura 5, 02-093 Warszawa, Poland
| | - Paweł Kowalczyk
- Institute of Experimental Physics, Faculty of Physics, University of Warsaw, ul. Pasteura 5, 02-093 Warszawa, Poland
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2
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Gerschmann J, Schwanke E, Ospelkaus S, Tiemann E. The electronic system and of LiCa. Mol Phys 2022. [DOI: 10.1080/00268976.2022.2122886] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/14/2022]
Affiliation(s)
- Julia Gerschmann
- Institute of Quantum Optics, Leibniz Universität Hannover, Hannover, Germany
- Laboratory for Nano- and Quantum Engineering, Leibniz Universität Hannover, Hannover, Germany
| | - Erik Schwanke
- Institute of Quantum Optics, Leibniz Universität Hannover, Hannover, Germany
- Laboratory for Nano- and Quantum Engineering, Leibniz Universität Hannover, Hannover, Germany
| | - Silke Ospelkaus
- Institute of Quantum Optics, Leibniz Universität Hannover, Hannover, Germany
- Laboratory for Nano- and Quantum Engineering, Leibniz Universität Hannover, Hannover, Germany
| | - Eberhard Tiemann
- Institute of Quantum Optics, Leibniz Universität Hannover, Hannover, Germany
- Laboratory for Nano- and Quantum Engineering, Leibniz Universität Hannover, Hannover, Germany
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3
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Schuster T, Flicker F, Li M, Kotochigova S, Moore JE, Ye J, Yao NY. Realizing Hopf Insulators in Dipolar Spin Systems. PHYSICAL REVIEW LETTERS 2021; 127:015301. [PMID: 34270282 DOI: 10.1103/physrevlett.127.015301] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/01/2019] [Revised: 09/24/2020] [Accepted: 04/19/2021] [Indexed: 06/13/2023]
Abstract
The Hopf insulator is a weak topological insulator characterized by an insulating bulk with conducting edge states protected by an integer-valued linking number invariant. The state exists in three-dimensional two-band models. We demonstrate that the Hopf insulator can be naturally realized in lattices of dipolar-interacting spins, where spin exchange plays the role of particle hopping. The long-ranged, anisotropic nature of the dipole-dipole interactions allows for the precise detail required in the momentum-space structure, while different spin orientations ensure the necessary structure of the complex phases of the hoppings. Our model features robust gapless edge states at both smooth edges, as well as sharp edges obeying a certain crystalline symmetry, despite the breakdown of the two-band picture at the latter. In an accompanying paper [T. Schuster et al., Phys. Rev. A 103, AW11986 (2021)PLRAAN2469-9926] we provide a specific experimental blueprint for implementing our proposal using ultracold polar molecules of ^{40}K^{87}Rb.
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Affiliation(s)
- Thomas Schuster
- Department of Physics, University of California, Berkeley, California 94720, USA
| | - Felix Flicker
- Department of Physics, University of California, Berkeley, California 94720, USA
- Rudolph Peierls Centre for Theoretical Physics, University of Oxford, Department of Physics, Clarendon Laboratory, Parks Road, Oxford OX1 3PU, United Kingdom
| | - Ming Li
- Department of Physics, Temple University, Philadelphia, Pennsylvania 19122, USA
| | | | - Joel E Moore
- Department of Physics, University of California, Berkeley, California 94720, USA
- Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Jun Ye
- JILA, National Institute of Standards and Technology and Department of Physics, University of Colorado, Boulder, Colorado 80309, USA
| | - Norman Y Yao
- Department of Physics, University of California, Berkeley, California 94720, USA
- Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
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4
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Persinger TD, Han J, Heaven MC. Electronic Spectroscopy and Photoionization of LiMg. J Phys Chem A 2021; 125:3653-3663. [PMID: 33882672 DOI: 10.1021/acs.jpca.1c01656] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Dimers consisting of an alkali metal bound to an alkaline earth metal are of interest from the perspectives of their bonding characteristics and their potential for being laser cooled to ultracold temperatures. There have been experimental and theoretical studies of many of these species, but spectroscopic data for LiMg and the LiMg+ cation are sparse. In this study, rotationally resolved electronic spectra for LiMg are presented. The ground state is confirmed to be X12Σ+ and observations of low-lying electronically excited states are reported for the first time. Reexamination of transitions in the near-UV spectral range indicates that previous band assignments should be revised. Two-color laser excitation techniques were used to determine an ionization energy of 4.7695(4) eV. This value is 1.2 eV below the previously reported experimental estimate. Vibrationally resolved spectra were obtained for LiMg+, yielding molecular constants that were consistent with a substantial strengthening of the bond on ionization.
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Affiliation(s)
- Thomas D Persinger
- Department of Chemistry, Emory University, Atlanta, Georgia 30322, United States
| | - Jiande Han
- Department of Chemistry, Emory University, Atlanta, Georgia 30322, United States
| | - Michael C Heaven
- Department of Chemistry, Emory University, Atlanta, Georgia 30322, United States
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Wang X, Liu W, Li Y, Wu J, Sovkov VB, Ma J, Onishchenko S, Li P, Fu Y, Li D, Fan Q, Xiao L, Jia S. Hyperfine structure of the NaCs b 3Π 2 state near the dissociation limit 3S 1/2 + 6P 3/2 observed with ultracold atomic photoassociation. Phys Chem Chem Phys 2020; 22:3809-3816. [PMID: 31872827 DOI: 10.1039/c9cp05870b] [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
We report new observations of the hyperfine structure in three ro-vibrational levels of the b3Π2 state of NaCs near the dissociation limit 3S1/2 + 6P3/2. The experiment was done via photoassociation of ultracold atoms in a dual-species dark-spot magneto-optical trap, and the spectra were measured as atomic trap losses. The simulation of the hyperfine structure showed that the greater part of the observed structure belongs to almost isolated levels of the b3Π2 state, but there are other parts of mixed character where the contribution from the 1Σ symmetry dominates.
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Affiliation(s)
- Xiaofeng Wang
- State Key Laboratory of Quantum Optics and Quantum Optics Devices, Institute of Laser Spectroscopy, Shanxi University, Wucheng Rd. 92, 030006 Taiyuan, China.
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6
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Green A, Li H, Toh JHS, Tang X, McCormick KC, Li M, Tiesinga E, Kotochigova S, Gupta S. Feshbach Resonances in p-Wave Three-Body Recombination within Fermi-Fermi Mixtures of Open-Shell 6Li and Closed-Shell 173Yb Atoms. PHYSICAL REVIEW. X 2020; 10:10.1103/PhysRevX.10.031037. [PMID: 34408918 PMCID: PMC8369980 DOI: 10.1103/physrevx.10.031037] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
We report on the observation of magnetic Feshbach resonances in a Fermi-Fermi mixture of ultracold atoms with extreme mass imbalance and on their unique p-wave dominated three-body recombination processes. Our system consists of open-shell alkali-metal 6Li and closed-shell 173Yb atoms, both spin polarized and held at various temperatures between 1 and 20 μK. We confirm that Feshbach resonances in this system are solely the result of a weak separation-dependent hyperfine coupling between the electronic spin of 6Li and the nuclear spin of 173Yb. Our analysis also shows that three-body recombination rates are controlled by the identical fermion nature of the mixture, even in the presence of s-wave collisions between the two species and with recombination rate coefficients outside the Wigner threshold regime at our lowest temperature. Specifically, a comparison of experimental and theoretical line shapes of the recombination process indicates that the characteristic asymmetric line shape as a function of applied magnetic field and a maximum recombination rate coefficient that is independent of temperature can only be explained by triatomic collisions with nonzero, p-wave total orbital angular momentum. The resonances can be used to form ultracold doublet ground-state molecules and to simulate quantum superfluidity in mass-imbalanced mixtures.
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Affiliation(s)
- Alaina Green
- Department of Physics, University of Washington, Seattle, Washington 98195, USA
| | - Hui Li
- Department of Physics, Temple University, Philadelphia, Pennsylvania 19122, USA
| | - Jun Hui See Toh
- Department of Physics, University of Washington, Seattle, Washington 98195, USA
| | - Xinxin Tang
- Department of Physics, University of Washington, Seattle, Washington 98195, USA
| | | | - Ming Li
- Department of Physics, Temple University, Philadelphia, Pennsylvania 19122, USA
| | - Eite Tiesinga
- Joint Quantum Institute and Joint Center for Quantum Information and Computer Science, National Institute of Standards and Technology and University of Maryland, Gaithersburg, Maryland 20899, USA
| | | | - Subhadeep Gupta
- Department of Physics, University of Washington, Seattle, Washington 98195, USA
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Passagem HF, Colín-Rodríguez R, Tallant J, Ventura da Silva PC, Bouloufa-Maafa N, Dulieu O, Marcassa LG. Continuous Loading of Ultracold Ground-State ^{85}Rb_{2} Molecules in a Dipole Trap Using a Single Light Beam. PHYSICAL REVIEW LETTERS 2019; 122:123401. [PMID: 30978081 DOI: 10.1103/physrevlett.122.123401] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/25/2018] [Revised: 02/10/2019] [Indexed: 06/09/2023]
Abstract
We have developed an approach to continuously load ultracold ^{85}Rb_{2} vibrational ground-state molecules into a crossed optical dipole trap from a magneto-optical trap. The technique relies on a single high-power light beam with a broad spectrum superimposed onto a narrow peak at an energy of about 9400 cm^{-1}. This single laser source performs all the required steps: the short-range photoassociation creating ground-state molecules after radiative emission, the cooling of the molecular vibrational population down to the lowest vibrational level v_{X}=0, and the optical trapping of these molecules. Furthermore, we probe by depletion spectroscopy and determine that 75% of the v_{X}=0 ground-state molecules are in the three lowest rotational levels J_{X}=0, 1, 2. The lifetime of the ultracold molecules in the optical dipole trap is limited to about 70 ms by off-resonant light scattering. The proposed technique opens perspectives for the formation of new molecular species in the ultracold domain, which are not yet accessible by well-established approaches.
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Affiliation(s)
- Henry Fernandes Passagem
- Instituto de Física de São Carlos, Universidade de São Paulo, Caixa Postal 369, 13560-970, São Carlos, São Paulo, Brazil
| | - Ricardo Colín-Rodríguez
- Instituto de Física de São Carlos, Universidade de São Paulo, Caixa Postal 369, 13560-970, São Carlos, São Paulo, Brazil
| | - Jonathan Tallant
- Instituto de Física de São Carlos, Universidade de São Paulo, Caixa Postal 369, 13560-970, São Carlos, São Paulo, Brazil
| | - Paulo Cesar Ventura da Silva
- Instituto de Física de São Carlos, Universidade de São Paulo, Caixa Postal 369, 13560-970, São Carlos, São Paulo, Brazil
| | - Nadia Bouloufa-Maafa
- Laboratoire Aimé Cotton, CNRS, Université Paris-Sud, ENS Cachan, Université Paris-Saclay, 91405 Orsay cedex, France
| | - Olivier Dulieu
- Laboratoire Aimé Cotton, CNRS, Université Paris-Sud, ENS Cachan, Université Paris-Saclay, 91405 Orsay cedex, France
| | - Luis Gustavo Marcassa
- Instituto de Física de São Carlos, Universidade de São Paulo, Caixa Postal 369, 13560-970, São Carlos, São Paulo, Brazil
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