1
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Poh YR, Morozov D, Kazmierczak NP, Hadt RG, Groenhof G, Yuen-Zhou J. Alternant Hydrocarbon Diradicals as Optically Addressable Molecular Qubits. J Am Chem Soc 2024; 146:15549-15561. [PMID: 38798142 DOI: 10.1021/jacs.4c04360] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/29/2024]
Abstract
High-spin molecules allow for bottom-up qubit design and are promising platforms for magnetic sensing and quantum information science. Optical addressability of molecular electron spins has also been proposed in first-row transition-metal complexes via optically detected magnetic resonance (ODMR) mechanisms analogous to the diamond-nitrogen-vacancy color center. However, significantly less progress has been made on the front of metal-free molecules, which can deliver lower costs and milder environmental impacts. At present, most luminescent open-shell organic molecules are π-diradicals, but such systems often suffer from poor ground-state open-shell characters necessary to realize a stable ground-state molecular qubit. In this work, we use alternancy symmetry to selectively minimize radical-radical interactions in the ground state, generating π-systems with high diradical characters. We call them m-dimers, referencing the need to covalently link two benzylic radicals at their meta carbon atoms for the desired symmetry. Through a detailed electronic structure analysis, we find that the excited states of alternant hydrocarbon m-diradicals contain important symmetries that can be used to construct ODMR mechanisms leading to ground-state spin polarization. The molecular parameters are set in the context of a tris(2,4,6-trichlorophenyl)methyl (TTM) radical dimer covalently tethered at the meta position, demonstrating the feasibility of alternant m-diradicals as molecular color centers.
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Affiliation(s)
- Yong Rui Poh
- Department of Chemistry and Biochemistry, University of California San Diego, La Jolla, California 92093, United States
| | - Dmitry Morozov
- Terra Quantum AG, Kornhausstrasse 25, St. Gallen 9000, Switzerland
| | - Nathanael P Kazmierczak
- Division of Chemistry and Chemical Engineering, Arthur Amos Noyes Laboratory of Chemical Physics, California Institute of Technology, Pasadena, California 91125, United States
| | - Ryan G Hadt
- Division of Chemistry and Chemical Engineering, Arthur Amos Noyes Laboratory of Chemical Physics, California Institute of Technology, Pasadena, California 91125, United States
| | - Gerrit Groenhof
- Nanoscience Center and Department of Chemistry, University of Jyväskylä, Jyväskylä 40014, Finland
| | - Joel Yuen-Zhou
- Department of Chemistry and Biochemistry, University of California San Diego, La Jolla, California 92093, United States
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2
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Zhu GZ, Lao G, Dickerson CE, Caram JR, Campbell WC, Alexandrova AN, Hudson ER. Extending the Large Molecule Limit: The Role of Fermi Resonance in Developing a Quantum Functional Group. J Phys Chem Lett 2024; 15:590-597. [PMID: 38198595 DOI: 10.1021/acs.jpclett.3c03177] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2024]
Abstract
Polyatomic molecules equipped with optical cycling centers (OCCs), enabling continuous photon scattering during optical excitation, are exciting candidates for advancing quantum information science. However, as these molecules grow in size and complexity, the interplay of complex vibronic couplings on optical cycling becomes a critical but relatively unexplored consideration. Here, we present an extensive exploration of Fermi resonances in large-scale OCC-containing molecules using high-resolution dispersed laser-induced fluorescence and excitation spectroscopy. These resonances manifest as vibrational coupling leading to intensity borrowing by combination bands near optically active harmonic bands, which require additional repumping lasers for effective optical cycling. To mitigate these effects, we explore altering the vibrational energy level spacing through substitutions on the phenyl ring or changes in the OCC itself. While the complete elimination of vibrational coupling in complex molecules remains challenging, our findings highlight significant mitigation possibilities, opening new avenues for optimizing optical cycling in large polyatomic molecules.
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Affiliation(s)
- Guo-Zhu Zhu
- Department of Physics and Astronomy, University of California, Los Angeles, California 90095, United States
| | - Guanming Lao
- Department of Physics and Astronomy, University of California, Los Angeles, California 90095, United States
| | - Claire E Dickerson
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095, United States
| | - Justin R Caram
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095, United States
- Center for Quantum Science and Engineering, University of California, Los Angeles, California 90095, United States
| | - Wesley C Campbell
- Department of Physics and Astronomy, University of California, Los Angeles, California 90095, United States
- Center for Quantum Science and Engineering, University of California, Los Angeles, California 90095, United States
- Challenge Institute for Quantum Computation, University of California, Los Angeles, California 90095, United States
| | - Anastassia N Alexandrova
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095, United States
- Center for Quantum Science and Engineering, University of California, Los Angeles, California 90095, United States
| | - Eric R Hudson
- Department of Physics and Astronomy, University of California, Los Angeles, California 90095, United States
- Center for Quantum Science and Engineering, University of California, Los Angeles, California 90095, United States
- Challenge Institute for Quantum Computation, University of California, Los Angeles, California 90095, United States
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3
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Dickerson CE, Chang C, Guo H, Alexandrova AN. Fully Saturated Hydrocarbons as Hosts of Optical Cycling Centers. J Phys Chem A 2022; 126:9644-9650. [PMID: 36519723 DOI: 10.1021/acs.jpca.2c06647] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Designing closed, laser-induced optical cycling transitions in trapped atoms or molecules is useful for quantum information processing, precision measurement, and quantum sensing. Larger molecules that feature such closed transitions are particularly desirable, as the increased degrees of freedom present new structures for optical control and enhanced measurements. The search for molecules with robust optical cycling centers is a challenge which requires design principles beyond trial-and-error. Two such principles are proposed for the particular M-O-R framework, where M is an alkaline earth metal radical, and R is a ligand: (1) Large, saturated hydrocarbons can serve as ligands, R, due to a substantial HOMO-LUMO gap that encloses the cycling transition, so long as the R group is rigid. (2) Electron-withdrawing groups, via induction, can enhance Franck-Condon factors (FCFs) of the optical cycling transition, as long as they do not disturb the locally linear structure in the M-O-R motif. With these tools in mind, larger molecules can be trapped and used as optical cycling centers, sometimes with higher FCFs than smaller molecules.
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Affiliation(s)
- Claire E Dickerson
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095, United States
| | - Cecilia Chang
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095, United States
| | - Han Guo
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095, United States
| | - Anastassia N Alexandrova
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095, United States
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4
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Lao G, Zhu GZ, Dickerson CE, Augenbraun BL, Alexandrova AN, Caram JR, Hudson ER, Campbell WC. Laser Spectroscopy of Aromatic Molecules with Optical Cycling Centers: Strontium(I) Phenoxides. J Phys Chem Lett 2022; 13:11029-11035. [PMID: 36413655 PMCID: PMC9720742 DOI: 10.1021/acs.jpclett.2c03040] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2022] [Accepted: 11/15/2022] [Indexed: 06/16/2023]
Abstract
We report the production and spectroscopic characterization of strontium(I) phenoxide (SrOC6H5 or SrOPh) and variants featuring electron-withdrawing groups designed to suppress vibrational excitation during spontaneous emission from the electronically excited state. Optical cycling closure of these species, which is the decoupling of the vibrational state changes from spontaneous optical decay, is found by dispersed laser-induced fluorescence spectroscopy to be high, in accordance with theoretical predictions. A high-resolution, rotationally resolved laser excitation spectrum is recorded for SrOPh, allowing the estimation of spectroscopic constants and identification of candidate optical cycling transitions for future work. The results confirm the promise of strontium phenoxides for laser cooling and quantum state detection at the single-molecule level.
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Affiliation(s)
- Guanming Lao
- Department
of Physics & Astronomy, University of
California Los Angeles, Los Angeles, California90095, United States
| | - Guo-Zhu Zhu
- Department
of Physics & Astronomy, University of
California Los Angeles, Los Angeles, California90095, United States
| | - Claire E. Dickerson
- Department
of Chemistry & Biochemistry, University
of California Los Angeles, Los
Angeles, California90095, United States
| | - Benjamin L. Augenbraun
- Department
of Physics, Harvard University, Cambridge, Massachusetts02138, United States
- Harvard-MIT
Center for Ultracold Atoms, Cambridge, Massachusetts02138, United States
| | - Anastassia N. Alexandrova
- Department
of Chemistry & Biochemistry, University
of California Los Angeles, Los
Angeles, California90095, United States
- Center
for Quantum Science and Engineering, University
of California, Los Angeles, California90095, United States
| | - Justin R. Caram
- Department
of Chemistry & Biochemistry, University
of California Los Angeles, Los
Angeles, California90095, United States
- Center
for Quantum Science and Engineering, University
of California, Los Angeles, California90095, United States
| | - Eric R. Hudson
- Department
of Physics & Astronomy, University of
California Los Angeles, Los Angeles, California90095, United States
- Center
for Quantum Science and Engineering, University
of California, Los Angeles, California90095, United States
- Challenge
Institute for Quantum Computation, University
of California, Los Angeles, California90095, United States
| | - Wesley C. Campbell
- Department
of Physics & Astronomy, University of
California Los Angeles, Los Angeles, California90095, United States
- Center
for Quantum Science and Engineering, University
of California, Los Angeles, California90095, United States
- Challenge
Institute for Quantum Computation, University
of California, Los Angeles, California90095, United States
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5
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Wright SC, Doppelbauer M, Hofsäss S, Christian Schewe H, Sartakov B, Meijer G, Truppe S. Cryogenic buffer gas beams of AlF, CaF, MgF, YbF, Al, Ca, Yb and NO – a comparison. Mol Phys 2022. [DOI: 10.1080/00268976.2022.2146541] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Sidney C. Wright
- Fritz Haber Institute of the Max Planck Society, Berlin, Germany
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6
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Augenbraun BL, Burchesky S, Winnicki A, Doyle JM. High-Resolution Laser Spectroscopy of a Functionalized Aromatic Molecule. J Phys Chem Lett 2022; 13:10771-10777. [PMID: 36374523 DOI: 10.1021/acs.jpclett.2c03041] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
We present a high-resolution laser spectroscopic study of the Ã2B2-X̃2A1 and B̃2B1-X̃2A1 transitions of calcium(I) phenoxide, CaOPh (CaOC6H5). The rotationally resolved band systems are analyzed using an effective Hamiltonian model and are accurately modeled as independent perpendicular (b- or c-type) transitions. The structure of calcium monophenoxide is compared to previously observed Ca-containing radicals, and implications for direct laser cooling are discussed. This work demonstrates that functionalization of aromatic molecules with optical cycling centers can preserve many of the properties needed for laser-based control.
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Affiliation(s)
- Benjamin L Augenbraun
- Department of Physics, Harvard University, Cambridge, Massachusetts02138, United States
- Harvard-MIT Center for Ultracold Atoms, Cambridge, Massachusetts02138, United States
| | - Sean Burchesky
- Department of Physics, Harvard University, Cambridge, Massachusetts02138, United States
- Harvard-MIT Center for Ultracold Atoms, Cambridge, Massachusetts02138, United States
| | - Andrew Winnicki
- Department of Physics, Harvard University, Cambridge, Massachusetts02138, United States
- Harvard-MIT Center for Ultracold Atoms, Cambridge, Massachusetts02138, United States
| | - John M Doyle
- Department of Physics, Harvard University, Cambridge, Massachusetts02138, United States
- Harvard-MIT Center for Ultracold Atoms, Cambridge, Massachusetts02138, United States
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7
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Mitra D, Lasner ZD, Zhu GZ, Dickerson CE, Augenbraun BL, Bailey AD, Alexandrova AN, Campbell WC, Caram JR, Hudson ER, Doyle JM. Pathway toward Optical Cycling and Laser Cooling of Functionalized Arenes. J Phys Chem Lett 2022; 13:7029-7035. [PMID: 35900113 DOI: 10.1021/acs.jpclett.2c01430] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Rapid and repeated photon cycling has enabled precision metrology and the development of quantum information systems using atoms and simple molecules. Extending optical cycling to structurally complex molecules would provide new capabilities in these areas, as well as in ultracold chemistry. Increased molecular complexity, however, makes realizing closed optical transitions more difficult. Building on already established strong optical cycling of diatomic, linear triatomic, and symmetric top molecules, recent work has pointed the way to cycling of larger molecules, including phenoxides. The paradigm for these systems is an optical cycling center bonded to a molecular ligand. Theory has suggested that cycling may be extended to even larger ligands, like naphthalene, pyrene, and coronene. Herein, we study optical excitation and fluorescent vibrational branching of CaO-[Formula: see text], SrO-[Formula: see text], and CaO-[Formula: see text] and find only weak decay to excited vibrational states, indicating a promising path to full quantum control and laser cooling of large arene-based molecules.
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Affiliation(s)
- Debayan Mitra
- Department of Physics, Harvard University, Cambridge, Massachusetts 02138, United States
- Harvard-MIT Center for Ultracold Atoms, Cambridge, Massachusetts 02138, United States
| | - Zack D Lasner
- Department of Physics, Harvard University, Cambridge, Massachusetts 02138, United States
- Harvard-MIT Center for Ultracold Atoms, Cambridge, Massachusetts 02138, United States
| | - Guo-Zhu Zhu
- Department of Physics and Astronomy, University of California, Los Angeles, California 90095, United States
- Center for Quantum Science and Engineering, University of California, Los Angeles, California 90095, United States
- Challenge Institute for Quantum Computation, University of California, Los Angeles, California 90095, United States
| | - Claire E Dickerson
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095, United States
| | - Benjamin L Augenbraun
- Department of Physics, Harvard University, Cambridge, Massachusetts 02138, United States
- Harvard-MIT Center for Ultracold Atoms, Cambridge, Massachusetts 02138, United States
| | - Austin D Bailey
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095, United States
| | - Anastassia N Alexandrova
- Center for Quantum Science and Engineering, University of California, Los Angeles, California 90095, United States
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095, United States
| | - Wesley C Campbell
- Department of Physics and Astronomy, University of California, Los Angeles, California 90095, United States
- Center for Quantum Science and Engineering, University of California, Los Angeles, California 90095, United States
- Challenge Institute for Quantum Computation, University of California, Los Angeles, California 90095, United States
| | - Justin R Caram
- Center for Quantum Science and Engineering, University of California, Los Angeles, California 90095, United States
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095, United States
| | - Eric R Hudson
- Department of Physics and Astronomy, University of California, Los Angeles, California 90095, United States
- Center for Quantum Science and Engineering, University of California, Los Angeles, California 90095, United States
- Challenge Institute for Quantum Computation, University of California, Los Angeles, California 90095, United States
| | - John M Doyle
- Department of Physics, Harvard University, Cambridge, Massachusetts 02138, United States
- Harvard-MIT Center for Ultracold Atoms, Cambridge, Massachusetts 02138, United States
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8
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Zhu GZ, Mitra D, Augenbraun BL, Dickerson CE, Frim MJ, Lao G, Lasner ZD, Alexandrova AN, Campbell WC, Caram JR, Doyle JM, Hudson ER. Functionalizing aromatic compounds with optical cycling centres. Nat Chem 2022; 14:995-999. [PMID: 35879444 DOI: 10.1038/s41557-022-00998-x] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2022] [Accepted: 06/14/2022] [Indexed: 12/13/2022]
Abstract
Molecular design principles provide guidelines for augmenting a molecule with a smaller group of atoms to realize a desired property or function. We demonstrate that these concepts can be used to create an optical cycling centre, the Ca(I)-O unit, that can be attached to a number of aromatic ligands, enabling the scattering of many photons from the resulting molecules without changing the molecular vibrational state. Such capability plays a central role in quantum state preparation and measurement, as well as laser cooling and trapping, and is therefore a prerequisite for many quantum science and technology applications. We provide further molecular design principles that indicate the ability to optimize and expand this work to an even broader class of molecules. This represents a great step towards a quantum functional group, which may serve as a generic qubit moiety that can be attached to a wide range of molecular structures and surfaces.
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Affiliation(s)
- Guo-Zhu Zhu
- Department of Physics and Astronomy, University of California, Los Angeles, CA, USA
| | - Debayan Mitra
- Harvard-MIT Center for Ultracold Atoms, Cambridge, MA, USA.,Department of Physics, Harvard University, Cambridge, MA, USA.,Department of Physics, Columbia University, New York, NY, USA
| | - Benjamin L Augenbraun
- Harvard-MIT Center for Ultracold Atoms, Cambridge, MA, USA.,Department of Physics, Harvard University, Cambridge, MA, USA
| | - Claire E Dickerson
- Department of Chemistry and Biochemistry, University of California, Los Angeles, CA, USA
| | - Michael J Frim
- Department of Physics, Harvard University, Cambridge, MA, USA
| | - Guanming Lao
- Department of Physics and Astronomy, University of California, Los Angeles, CA, USA
| | - Zack D Lasner
- Harvard-MIT Center for Ultracold Atoms, Cambridge, MA, USA.,Department of Physics, Harvard University, Cambridge, MA, USA
| | - Anastassia N Alexandrova
- Department of Chemistry and Biochemistry, University of California, Los Angeles, CA, USA.,Center for Quantum Science and Engineering, University of California, Los Angeles, CA, USA
| | - Wesley C Campbell
- Department of Physics and Astronomy, University of California, Los Angeles, CA, USA.,Center for Quantum Science and Engineering, University of California, Los Angeles, CA, USA.,Challenge Institute for Quantum Computation, University of California, Los Angeles, CA, USA
| | - Justin R Caram
- Department of Chemistry and Biochemistry, University of California, Los Angeles, CA, USA.,Center for Quantum Science and Engineering, University of California, Los Angeles, CA, USA
| | - John M Doyle
- Harvard-MIT Center for Ultracold Atoms, Cambridge, MA, USA.,Department of Physics, Harvard University, Cambridge, MA, USA
| | - Eric R Hudson
- Department of Physics and Astronomy, University of California, Los Angeles, CA, USA. .,Center for Quantum Science and Engineering, University of California, Los Angeles, CA, USA. .,Challenge Institute for Quantum Computation, University of California, Los Angeles, CA, USA.
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9
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Vilas NB, Hallas C, Anderegg L, Robichaud P, Winnicki A, Mitra D, Doyle JM. Magneto-optical trapping and sub-Doppler cooling of a polyatomic molecule. Nature 2022; 606:70-74. [PMID: 35650357 DOI: 10.1038/s41586-022-04620-5] [Citation(s) in RCA: 30] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2021] [Accepted: 03/04/2022] [Indexed: 11/09/2022]
Abstract
Laser cooling and trapping1,2, and magneto-optical trapping methods in particular2, have enabled groundbreaking advances in science, including Bose-Einstein condensation3-5, quantum computation with neutral atoms6,7 and high-precision optical clocks8. Recently, magneto-optical traps (MOTs) of diatomic molecules have been demonstrated9-12, providing access to research in quantum simulation13 and searches for physics beyond the standard model14. Compared with diatomic molecules, polyatomic molecules have distinct rotational and vibrational degrees of freedom that promise a variety of transformational possibilities. For example, ultracold polyatomic molecules would be uniquely suited to applications in quantum computation and simulation15-17, ultracold collisions18, quantum chemistry19 and beyond-the-standard-model searches20,21. However, the complexity of these molecules has so far precluded the realization of MOTs for polyatomic species. Here we demonstrate magneto-optical trapping of a polyatomic molecule, calcium monohydroxide (CaOH). After trapping, the molecules are laser cooled in a blue-detuned optical molasses to a temperature of 110 μK, which is below the Doppler cooling limit. The temperatures and densities achieved here make CaOH a viable candidate for a wide variety of quantum science applications, including quantum simulation and computation using optical tweezer arrays15,17,22,23. This work also suggests that laser cooling and magneto-optical trapping of many other polyatomic species24-27 will be both feasible and practical.
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Affiliation(s)
- Nathaniel B Vilas
- Department of Physics, Harvard University, Cambridge, MA, USA. .,Harvard-MIT Center for Ultracold Atoms, Cambridge, MA, USA.
| | - Christian Hallas
- Department of Physics, Harvard University, Cambridge, MA, USA.,Harvard-MIT Center for Ultracold Atoms, Cambridge, MA, USA
| | - Loïc Anderegg
- Department of Physics, Harvard University, Cambridge, MA, USA.,Harvard-MIT Center for Ultracold Atoms, Cambridge, MA, USA
| | - Paige Robichaud
- Department of Physics, Harvard University, Cambridge, MA, USA.,Harvard-MIT Center for Ultracold Atoms, Cambridge, MA, USA
| | - Andrew Winnicki
- Department of Physics, Harvard University, Cambridge, MA, USA.,Harvard-MIT Center for Ultracold Atoms, Cambridge, MA, USA
| | - Debayan Mitra
- Department of Physics, Harvard University, Cambridge, MA, USA.,Harvard-MIT Center for Ultracold Atoms, Cambridge, MA, USA.,Department of Physics, Columbia University, New York, NY, USA
| | - John M Doyle
- Department of Physics, Harvard University, Cambridge, MA, USA.,Harvard-MIT Center for Ultracold Atoms, Cambridge, MA, USA
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10
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Telfah H, Sharma K, Paul AC, Riyadh SMS, Miller TA, Liu J. A combined experimental and computational study on the transition of the calcium isopropoxide radical as a candidate for direct laser cooling. Phys Chem Chem Phys 2022; 24:8749-8762. [PMID: 35352070 DOI: 10.1039/d1cp04107j] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Vibronically resolved laser-induced fluorescence/dispersed fluorescence (LIF/DF) and cavity ring-down (CRD) spectra of the electronic transition of the calcium isopropoxide [CaOCH(CH3)2] radical have been obtained under jet-cooled conditions. An essentially constant energy separation of 68 cm-1 has been observed for the vibrational ground levels and all fundamental vibrational levels accessed in the LIF measurement. To simulate the experimental spectra and assign the recorded vibronic bands, Franck-Condon (FC) factors and vibrational branching ratios (VBRs) are predicted from vibrational modes and their frequencies calculated using the complete-active-space self-consistent field (CASSCF) and equation-of-motion coupled-cluster singles and doubles (EOM-CCSD) methods. Combined with the calculated electronic transition energy, the computational results, especially those from the EOM-CCSD calculations, reproduced the experimental spectra with considerable accuracy. The experimental and computational results suggest that the FC matrix for the studied electronic transition is largely diagonal, but transitions from the vibrationless levels of the à state to the X̃-state levels of the CCC bending (ν14 and ν15), CaO stretch (ν13), and CaOC asymmetric stretch (ν9 and ν11) modes also have considerable intensities. Transitions to low-frequency in-plane [ν17(a')] and out-of-plane [ν30(a'')] CaOC bending modes were observed in the experimental LIF/DF spectra, the latter being FC-forbidden but induced by the pseudo-Jahn-Teller (pJT) effect. Both bending modes are coupled to the CaOC asymmetric stretch mode via the Duschinsky rotation, as demonstrated in the DF spectra obtained by pumping non-origin vibronic transitions. The pJT interaction also induces transitions to the ground-state vibrational level of the ν10(a') mode, which has the CaOC bending character. Our combined experimental and computational results provide critical information for future direct laser cooling of the target molecule and other alkaline earth monoalkoxide radicals.
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Affiliation(s)
- Hamzeh Telfah
- Department of Chemistry, University of Louisville, Louisville, Kentucky 40292, USA.
| | - Ketan Sharma
- Department of Chemistry, The Ohio State University, Columbus, Ohio 43210, USA
| | - Anam C Paul
- Department of Chemistry, University of Louisville, Louisville, Kentucky 40292, USA.
| | - S M Shah Riyadh
- Department of Physics and Astronomy, University of Louisville, Louisville, Kentucky 40292, USA
| | - Terry A Miller
- Department of Chemistry, The Ohio State University, Columbus, Ohio 43210, USA
| | - Jinjun Liu
- Department of Chemistry, University of Louisville, Louisville, Kentucky 40292, USA. .,Department of Physics and Astronomy, University of Louisville, Louisville, Kentucky 40292, USA
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11
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Augenbraun BL, Frenett A, Sawaoka H, Hallas C, Vilas NB, Nasir A, Lasner ZD, Doyle JM. Zeeman-Sisyphus Deceleration of Molecular Beams. PHYSICAL REVIEW LETTERS 2021; 127:263002. [PMID: 35029484 DOI: 10.1103/physrevlett.127.263002] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/07/2021] [Accepted: 11/01/2021] [Indexed: 06/14/2023]
Abstract
We present a robust, continuous molecular decelerator that employs high magnetic fields and few optical pumping steps. CaOH molecules are slowed, accumulating at low velocities in a range sufficient for loading both magnetic and magneto-optical traps. During the slowing, the molecules scatter only seven photons, removing around 8 K of energy. Because large energies can be removed with only a few spontaneous radiative decays, this method can in principle be applied to nearly any paramagnetic atomic or molecular species, opening a general path to trapping of complex molecules.
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Affiliation(s)
- Benjamin L Augenbraun
- Department of Physics, Harvard University, Cambridge, Massachusetts 02138, USA and Harvard-MIT Center for Ultracold Atoms, Cambridge, Massachusetts 02138, USA
| | - Alexander Frenett
- Department of Physics, Harvard University, Cambridge, Massachusetts 02138, USA and Harvard-MIT Center for Ultracold Atoms, Cambridge, Massachusetts 02138, USA
| | - Hiromitsu Sawaoka
- Department of Physics, Harvard University, Cambridge, Massachusetts 02138, USA and Harvard-MIT Center for Ultracold Atoms, Cambridge, Massachusetts 02138, USA
| | - Christian Hallas
- Department of Physics, Harvard University, Cambridge, Massachusetts 02138, USA and Harvard-MIT Center for Ultracold Atoms, Cambridge, Massachusetts 02138, USA
| | - Nathaniel B Vilas
- Department of Physics, Harvard University, Cambridge, Massachusetts 02138, USA and Harvard-MIT Center for Ultracold Atoms, Cambridge, Massachusetts 02138, USA
| | - Abdullah Nasir
- Department of Physics, Harvard University, Cambridge, Massachusetts 02138, USA and Harvard-MIT Center for Ultracold Atoms, Cambridge, Massachusetts 02138, USA
| | - Zack D Lasner
- Department of Physics, Harvard University, Cambridge, Massachusetts 02138, USA and Harvard-MIT Center for Ultracold Atoms, Cambridge, Massachusetts 02138, USA
| | - John M Doyle
- Department of Physics, Harvard University, Cambridge, Massachusetts 02138, USA and Harvard-MIT Center for Ultracold Atoms, Cambridge, Massachusetts 02138, USA
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12
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Xia W, Ma H, Bian W. Production of ultracold CaCCH and SrCCH molecules by direct laser cooling: A theoretical study based on accurate ab initio calculations. J Chem Phys 2021; 155:204304. [PMID: 34852476 DOI: 10.1063/5.0072013] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Laser cooling of polyatomic molecules to the ultracold regime may enable some new science and technology applications; however, the related study is still at its very early stage. Here, by means of accurate ab initio and dynamical calculations, we identify two new candidate tetratomic molecules that are suitable for laser cooling and demonstrate the feasibility and advantage of two laser cooling schemes that are able to produce ultracold CaCCH and SrCCH molecules. The internally contracted multiconfiguration reference configuration interaction method is applied, and excellent agreement is achieved between the computed and experimental spectroscopic data. We find that the X2Σ1/2 +→A2Π1/2 transitions for both candidates feature diagonal Franck-Condon factors, short radiative lifetimes, and no interference from intermediate electronic states. In addition, the crossings with higher electronic states do not interfere. We further construct feasible laser cooling schemes for CaCCH and SrCCH, each of which allows scattering 104 photons for direct laser cooling. The estimated Doppler temperatures for both CaCCH and SrCCH are on the order of μK.
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Affiliation(s)
- Wensha Xia
- Beijing National Laboratory for Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
| | - Haitao Ma
- Beijing National Laboratory for Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
| | - Wensheng Bian
- Beijing National Laboratory for Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
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13
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Lavroff RH, Pennington DL, Hua AS, Li BY, Williams JA, Alexandrova AN. Recent Innovations in Solid-State and Molecular Qubits for Quantum Information Applications. J Phys Chem A 2021; 125:9567-9570. [PMID: 34758615 DOI: 10.1021/acs.jpca.1c08677] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Robert H Lavroff
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, California 90095-1569, United States
| | - Doran L Pennington
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, California 90095-1569, United States
| | - Ash Sueh Hua
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, California 90095-1569, United States
| | - Barry Yangtao Li
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, California 90095-1569, United States
| | - Jillian A Williams
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, California 90095-1569, United States
| | - Anastassia N Alexandrova
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, California 90095-1569, United States
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14
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Lavroff RH, Pennington DL, Hua AS, Li BY, Williams JA, Alexandrova AN. Recent Innovations in Solid-State and Molecular Qubits for Quantum Information Applications. J Phys Chem B 2021; 125:12111-12114. [PMID: 34758628 DOI: 10.1021/acs.jpcb.1c08679] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Robert H Lavroff
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, California 90095-1569, United States
| | - Doran L Pennington
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, California 90095-1569, United States
| | - Ash Sueh Hua
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, California 90095-1569, United States
| | - Barry Yangtao Li
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, California 90095-1569, United States
| | - Jillian A Williams
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, California 90095-1569, United States
| | - Anastassia N Alexandrova
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, California 90095-1569, United States
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15
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Lavroff RH, Pennington DL, Hua AS, Li BY, Williams JA, Alexandrova AN. Recent Innovations in Solid-State and Molecular Qubits for Quantum Information Applications. J Phys Chem Lett 2021; 12:10742-10745. [PMID: 34758627 DOI: 10.1021/acs.jpclett.1c03269] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Affiliation(s)
- Robert H Lavroff
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, California 90095-1569, United States
| | - Doran L Pennington
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, California 90095-1569, United States
| | - Ash Sueh Hua
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, California 90095-1569, United States
| | - Barry Yangtao Li
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, California 90095-1569, United States
| | - Jillian A Williams
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, California 90095-1569, United States
| | - Anastassia N Alexandrova
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, California 90095-1569, United States
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