Direct laser cooling schemes for the triatomic SOH and SeOH molecules based on ab initio electronic properties

Liu, Li; Yang, Chuan‐Lu; Sun, Zhaopeng; Wang, Meishan; Ma, Xiao‐Guang

doi:10.1039/d0cp04963h

Cited by 4 publications

(3 citation statements)

References 23 publications

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“…Further studies have also been carried out such as cooling CaOH to the sub-Doppler temperature, accurate determination of vibrational branching ratios (VBRs) and radiative lifetimes for YbOH (Baum et al, 2021;Vilas N et al, 2022). Other theoretical and experimental groups have also made important contributions to this emerging field (O' Rourke and Hutzler, 2019;Isaev et al, 2017;Liu et al, 2021;Xia et al, 2021;Paul et al, 2019;Ivanov et al, 2020a;Ivanov et al, 2020b;Ivanov et al, 2020c).…”

Section: Introductionmentioning

confidence: 99%

Production of ultracold polyatomic molecules with strong polarity by laser cooling: A detailed theoretical study on CaNC and SrNC

Xia

Cao

et al. 2022

Front. Chem.

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Laser cooling molecules to the ultracold regime is the prerequisite for many novel science and technologies. It is desirable to take advantage of theoretical approaches to explore polyatomic molecular candidates, which are capable of being cooled to the ultracold regime. In this work, we explore two polyatomic candidates, CaNC and SrNC, which are suitable for laser cooling. These molecules possess impressively large permanent dipole moments (∼6 Debye), which is preferred for applications using an external electric field. High-level ab initio calculations are carried out to reveal electronic structures of these molecules, and the calculated spectroscopic constants agree very well with the available experimental data. For each molecule, the Franck-Condon factor matrix is calculated and shows a diagonal distribution. The radiative lifetimes for CaNC and SrNC are estimated to be 15.5 and 15.8 ns, respectively. Based upon the features of various electronic states and by choosing suitable spin-orbit states, we construct two feasible laser cooling schemes for the two molecules, each of which allows scattering nearly 10000 photons for direct laser cooling. These indicate that CaNC and SrNC are excellent ultracold polyatomic candidates with strong polarity.

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Section: Introductionmentioning

confidence: 99%

Production of ultracold polyatomic molecules with strong polarity by laser cooling: A detailed theoretical study on CaNC and SrNC

Xia

Cao

et al. 2022

Front. Chem.

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“…A further conjecture can be made based on the current framework that the type (c) molecule also has the potential to be laser-coolable as long as the bond lengths and bond angles are similar between the upper and lower states. In fact, very recent studies 28 indeed propose that bent molecules such as SOH and CaSH can also be good laser-coolable molecules. The current work helps rationalize their hypothesis.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

Neglected Importance of Anharmonicity in Quantifying the Renner–Teller Effect

2022

ACS Omega

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Linear molecules in degenerate electronic states are influenced by the Renner–Teller (RT) effect. Currently the formula to quantify this vibronic interaction only considers the harmonic term. However, such a harmonic formula cannot well describe molecules that have double-well potential along the bending coordinate. In this work, we propose a new formula to quantify the RT effect by explicitly including the anharmonic term. A sign function and a delta function are additionally included to distinguish different scenarios. It is mathematically proved that the new formula is capable of differentiating different degrees of RT splitting. Representative molecules of different types are calculated. According to the new formula, molecules experiencing a weak RT effect have a positive parameter smaller than 1. For those experiencing a medium RT effect, the parameter will be negative. For others experiencing a large RT effect, the parameter will be larger than 1.

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“…2019年, Ivanov等 [20] 首先利用运动方程耦合簇 (equation-of-motion coupled-cluster, EOM-CC)方法对由碱土金属原子与负电性配体组合的线性多原子衍生物(MR: M = Ca, Sr, Ba; R = H -, F -, CCH -, OH -等)进行了系统研究, 他们指出具有对角Franck-Condon (FC)因子的激光制冷目标分子通常也具有小的量子缺陷(quantum defect). 2020年, Augenbraun等 [21] 通过理论分析提出可以冷却非对称多原子分子, 评估了7类非对称分子 (MSH, MNH 2 , MSCH 3 , MNHCH 3 , MOCH(CH 3 ) 2 , MOC 2 H 5 , MC 5 H 4 CH 3 ; M = Ca, Mg, Sr, Ba)作为激光冷却目标分子的可能性. 同年, Liu等 [22] 从理论上给出了冷却非线性分子SOH和SeOH可能的光学循环方案.…”

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High-precision electron structure calculation of CaSH molecules and theoretical analysis of its application to laser-cooled target molecules

Feng,

Suo,

Han

et al. 2024

Acta Phys. Sin.

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The CaSH molecule is an important target in the field of laser cooling of non-linear polyatomic molecules. Successful cooling of this molecule could surpass the technical limitations of diatomic and linear triatomic molecules in laser cooling. To identify the possible optical cycle in cooling CaSH, precise geometries of the CaSH ground state and the three lowest excited states, along with their excitation energies, are determined by utilizing the EA-EOM-CCSD (Electron attachment equation-of-motion coupled cluster singles and doubles) method, in combination with energy extrapolation using cc-pVXZ/cc-pCVXZ(X=T, Q) serial basis sets. Geometric parameters of the ground state $mathop Xlimits^ sim $2A' were found to be RCaS=2.564Å; RSH=1.357Å; ∠CaSH=91.0°. Additionally, the equilibrium geometries of three excited states are also obtained. The $mathop Blimits^ sim $2A'' state has a similar equilibrium structure to the ground state, while the $mathop Alimits^ sim $2A' and $mathop Climits^ sim $2A' states exhibit significant conformer distortions. Specifically, the CaS bond of the $mathop Alimits^ sim $2A' and $mathop Climits^ sim $2A' states tend to contract, and the CaSH angel bends by 5 relative to the ground state. The vertical excitation energies from the ground state to $mathop Alimits^ sim $2A'、$mathop Blimits^ sim $2A'' and $mathop Climits^ sim $2A' are of 1.898eV, 1.945eV and 1.966eV, respectively, which are in good agreement with the previous experimental results. Moreover, the potential energy surfaces of the four lowest electronic states of CaSH were calculated by EA-EOM-CCSD with 3ζ level of basis sets. The nuclear equations of motion were solved to obtain the vibrational frequencies of the CaS bond stretching and CaSH bending. The vibrational frequencies of the (0,1,0) mode (the CaS stretching) of four states are 316 cm-1, 315 cm-1, 331 cm-1 and 325 cm-1, which are in close agreement with the available experimental results. The frequencies of the CaSH bending mode are presented for the first time, with the value of 357 cm-1, 396 cm-1, 384 cm-1, 411 cm-1 for the $mathop Xlimits^ sim $2A', $mathop Alimits^ sim $2A', $mathop Blimits^ sim $2A'' and $mathop Climits^ sim $2A'states, respectively. Theoretical calculations give the Frank-Condon factors of 0.9268, 0.9958 and 0.9248 for the $mathop Xlimits^ sim $2A'(0,0,0) to $mathop Alimits^ sim $2A'(0,0,0), $mathop Blimits^ sim $2A''(0,0,0) and $mathop Climits^ sim $2A'(0,0,0) transitions. All three excited states are the bright states with considerable oscillator strength to the ground state. Based on the Frank-Condon factor and lifetime of excited states, the $mathop Xlimits^ sim $2A'(0,0,0) → $mathop Blimits^ sim $2A''(0,0,0) transition is suggested as the main cooling cycle for the CaSH molecule. The corresponding pump light wavelength is 678 nm. By exciting the vibrational excited states (0,1,0) and (0,0,1) of the $mathop Xlimits^ sim $2A' state to $mathop Alimits^ sim $2A'(0,0,0) using lasers at 664 nm and 668 nm, respectively, the optical cooling branch ratio of CaSH is expected to exceed 0.9998.

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Direct laser cooling schemes for the triatomic SOH and SeOH molecules based on ab initio electronic properties

Abstract: Direct laser cooling schemes are constructed for the triatomic SOH and SeOH molecules by using a newly developed method to identify polyatomic molecules suitable for direct laser cooling and to calculate the Franck–Condon factors.

Cited by 4 publications

References 23 publications

Production of ultracold polyatomic molecules with strong polarity by laser cooling: A detailed theoretical study on CaNC and SrNC

Production of ultracold polyatomic molecules with strong polarity by laser cooling: A detailed theoretical study on CaNC and SrNC

Neglected Importance of Anharmonicity in Quantifying the Renner–Teller Effect

High-precision electron structure calculation of CaSH molecules and theoretical analysis of its application to laser-cooled target molecules

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