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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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Zhang C, Hutzler NR, Cheng L. Intensity-Borrowing Mechanisms Pertinent to Laser Cooling of Linear Polyatomic Molecules. J Chem Theory Comput 2023. [PMID: 37384588 DOI: 10.1021/acs.jctc.3c00408] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/01/2023]
Abstract
A study of the intensity-borrowing mechanisms important to optical cycling transitions in laser-coolable polyatomic molecules arising from non-adiabatic coupling, contributions beyond the Franck-Condon approximation, and Fermi resonances is reported. It has been shown to be necessary to include non-adiabatic coupling to obtain computational accuracy that is sufficient to be useful for laser cooling of molecules. The predicted vibronic branching ratios using perturbation theory based on the non-adiabatic mechanisms have been demonstrated to agree well with those obtained from variational discrete variable representation calculations for representative molecules including CaOH, SrOH, and YbOH. The electron-correlation and basis-set effects on the calculated transition properties, including the vibronic coupling constants, the spin-orbit coupling matrix elements, and the transition dipole moments, and on the calculated branching ratios have been thoroughly studied. The vibronic branching ratios predicted using the present methodologies demonstrate that RaOH is a promising radioactive molecule candidate for laser cooling.
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Affiliation(s)
- Chaoqun Zhang
- Department of Chemistry, The Johns Hopkins University, Baltimore, Maryland 21218, United States
| | - Nicholas R Hutzler
- Division of Physics, Mathematics, and Astronomy, California Institute of Technology, Pasadena, California 91125, United States
| | - Lan Cheng
- Department of Chemistry, The Johns Hopkins University, Baltimore, Maryland 21218, United States
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