Electronic, structural and vibrational properties of calcium monohydride

Habli, Héla; Jellali, Soulef; Oujia, Brahim

doi:10.1088/1402-4896/ab450b

Cited by 3 publications

(3 citation statements)

References 67 publications

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“…In order to obtain accurate structural and spectroscopic properties within the Born-Oppenheimer approximation, we have adopted the computational scheme successfully applied to the ground and excited states interactions between heteronuclear alkali metal dimers and mixed alkali–AEM ions. − Hence, we have realized a non-relativistic electronic-structure computation of the neutral and cationic systems involving the radioactive atom Fr [Fr 2 , Fr–AEM + (AEM = Ca, Sr, Ba)]. The investigated dissociation limits of Fr 2 homonuclear dimer are {Fr(7s) + Fr(7s, 7p, 6d, 8s, 8p)}.…”

Section: Theoretical Methodsmentioning

confidence: 99%

Non-Relativistic Electronic-Structure Computation of Neutral and Cationic Systems [Fr₂, Fr–AEM⁺ (AEM= Ca, Sr, Ba)]

Jellali

Habli

2022

J. Phys. Chem. A

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The experimental field of ultracold ion-atom mixtures including an alkali-metal atom and an alkaline-earthmetal ion as well as of homonuclear alkali dimers has paved the way for creating and manipulating the ultracold molecules. The present paper is focused on a study of molecules such us francium dimer and a comparative spectroscopic investigation of the cationic systems Fr−(Ca + , Sr + , Ba + ). We adopt a computational scheme without spin−orbit coupling reposed on the full configuration interaction and semi-empirical pseudo-potential theory of the atomic cores Fr + , Ca 2+ , Sr 2+ , and Ba 2+ with extended and optimized basis sets. We have determined the adiabatic potentials with their relative spectroscopic constants, the electric dipole moments and the vibrational levels spacings for the 1,3 Σ u,g + and 1,3 Σ + electronic states for Fr 2 and Fr−AEM + , respectively, correlated toward {Fr(7s) + Fr(7s, 7p, 6d, 8s, 8p)}, {Ca(4s 2 , 4s4p, 4s3d), Sr(5s 2 , 5s5p, 5s4d), Ba(6s 2 , 6s6p, 6s5d) + Fr + }, and {Ca + (4s, 3d), Sr + (5s, 4d), Ba + (6s, 5d) + Fr(7s, 7p)}. The accuracy and reliability of the current results are discussed by comparing with theoretical data available in the literature. The occurrence of some avoided crossings between the neighboring electronic states is leading to a charge or excitation transfer for atom−ion collisions in the diverse charge or excited states. The Σ + −Σ + transitions are determined in order to evaluate the future radiative lifetimes of vibrational states serving the direct laser cooling.

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Section: Theoretical Methodsmentioning

confidence: 99%

Non-Relativistic Electronic-Structure Computation of Neutral and Cationic Systems [Fr₂, Fr–AEM⁺ (AEM= Ca, Sr, Ba)]

Jellali

Habli

2022

J. Phys. Chem. A

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“…Calcium monohydride has attracted significant attention in the fields of quantum chemistry, molecular spectroscopy, and astrophysics. One reason for this is the importance of the spectroscopic characteristics of the CaH molecule in simulating and analyzing astrophysical phenomena, given its prevalence in various interstellar environments. , Commencing with Mulliken’s inaugural spectroscopic study of the CaH molecule in 1925, extensive studies for electronic states, − ro-vibrational states, − and key properties such as the permanent electric dipole moment , of the CaH molecule have been carried out. On the other hand, the CaH molecule has a relatively simple ground-state hyperfine level structure, shorter excited-state lifetimes, and highly diagonal Franck–Condon factors for its X 2 Σ + -A 2 Π 1/2 and B 2 Σ + -A 2 Π 1/2 transitions, , making it well-suited for laser cooling of cold molecules and magneto-optical trapping.…”

Section: Introductionmentioning

confidence: 99%

A Neural Network Potential Energy Surface and Quantum Dynamics Study of Ca(¹S) + H₂(v₀ = 0, j₀ = 0) → CaH + H Reaction

Chen,

Mao,

Yang

et al. 2024

ACS Omega

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The reactive collision between Ca and H 2 molecules has attracted great interest experimentally due to the key role of the product CaH molecule in the field of astrophysics and cold molecules. However, quantum dynamics calculations for this system have not been reported due to the lack of a global potential energy surface (PES). Herein, a globally accurate PES of the ground-state CaH 2 is developed by combining 11365 high-level ab initio points and permutation invariant polynomial neural network method. Based on the newly constructed PES, the state-to-state quantum dynamics calculations for the Ca( 1 S) + H 2 (v 0 = 0, j 0 = 0) → CaH + H reaction are carried out using the time-dependent wave packet method. The dynamic results reveal that the reaction follows the complex-forming mechanism near the reactive threshold, whereas both the indirect insertion mechanism and direct abstraction mechanism have effects at higher collision energies. The newly constructed PES can be used to further study the influence of isotope substitution, rovibrational excitation, and spatial orientation of reactant molecules on reaction dynamics.

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“…CaH广泛存在于太阳黑子、恒星、星云和星际介质中, 其光谱数据在天体物理分析和模拟中非常重要 [39−42] . 例如对于矮星的光谱分析中, 科学家们利用CaH低重力光谱特征作为年龄指标, 观察并分析各种矮星的光谱以研究其剩余年龄上限 [43] .…”

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Theoretical investigation into spectrum of <inline-formula><tex-math id="M232">\begin{document}${{{\bf{A}}}}^{{\boldsymbol{2}}}{{\boldsymbol{\Pi}} }_{{\boldsymbol{1/2}}}{\boldsymbol{\leftarrow}} {{{\bf{X}}}}^{{\boldsymbol{2}}}{{\boldsymbol{\Sigma}} }_{{\boldsymbol{1/2}}}$\end{document}</tex-math><alternatives><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="16-20210522_M232.jpg"/><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="16-20210522_M232

华东师范大学物理系¹,

华东师范大学²,

华东师范大学精密光谱科学与技术国家重点实验室³

2021

Acta Phys. Sin.

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Laser cooling and trapping of neutral molecules has made substantial progress in the past few years. On one hand, molecules have more complex energy level structures than atoms, thus bringing great challenges to direct laser cooling and trapping; on the other hand, cold molecules show great advantages in cold molecular collisions and cold chemistry, as well as the applications in many-body interactions and fundamental physics such as searching for fundamental symmetry violations. In recent years, polar diatomic molecules such as SrF, YO, and CaF have been demonstrated experimentally in direct laser cooling techniques and magneto-optic traps (MOTs), all of which require a comprehensive understanding of their molecular internal level structures. Other suitable candidates have also been proposed, such as YbF, MgF, BaF, HgF or even SrOH and YbOH, some of which are already found to play important roles in searching for variations of fundamental constants and the measurement of the electron’s Electric Dipole Moment (eEDM). As early as 2004, the CaH molecule was selected as a good candidate for laser cooling and magneto-optical trapping. In this article, we first theoretically investigate the Franck−Condon factors of CaH in the <inline-formula><tex-math id="M233">\begin{document}${{\rm{A}}}^{2}\Pi _{1/2}\leftarrow {{\rm{X}}}^{2}\Sigma _{1/2}$\end{document}</tex-math><alternatives><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="16-20210522_M233.jpg"/><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="16-20210522_M233.png"/></alternatives></inline-formula> transition by the Morse potential method, the closed-form approximation method and the Rydberg-Klein-Rees method separately, and prove that Franck−Condon factor matrix between <inline-formula><tex-math id="M234">\begin{document}$ {\mathrm{X}}^{2}\Sigma _{1/2} $\end{document}</tex-math><alternatives><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="16-20210522_M234.jpg"/><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="16-20210522_M234.png"/></alternatives></inline-formula> state and <inline-formula><tex-math id="M235">\begin{document}$ {\mathrm{A}}^{2}\Pi _{1/2} $\end{document}</tex-math><alternatives><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="16-20210522_M235.jpg"/><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="16-20210522_M235.png"/></alternatives></inline-formula>state is highly diagonalized, and indicate that sum of f00, f01 and f02 for each molecule is greater than 0.9999 and almost 1 × 104 photons can be scattered to slow the molecules with merely three lasers. The molecular hyperfine structures of <inline-formula><tex-math id="M236">\begin{document}$ {X}^{2}\Sigma _{1/2} $\end{document}</tex-math><alternatives><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="16-20210522_M236.jpg"/><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="16-20210522_M236.png"/></alternatives></inline-formula>, as well as the transitions and associated hyperfine branching ratios in the <inline-formula><tex-math id="M237">\begin{document}${{\rm{A}}}^{2}\Pi _{1/2}\left(J=1/2, \mathrm{ }+\right)\leftarrow {{\rm{X}}}^{2}\Sigma _{1/2}\left(N=1, \mathrm{ }-\right)$\end{document}</tex-math><alternatives><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="16-20210522_M237.jpg"/><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="16-20210522_M237.png"/></alternatives></inline-formula> transition of CaH, are examined via the effective Hamiltonian approach. According to these results, in order to fully cover the hyperfine manifold originating from <inline-formula><tex-math id="M238">\begin{document}$ |X, \mathrm{ }N=1, -\rangle $\end{document}</tex-math><alternatives><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="16-20210522_M238.jpg"/><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="16-20210522_M238.png"/></alternatives></inline-formula>, we propose the sideband modulation scheme that at least two electro-optic modulators (EOMs) should be required for CaH when detuning within 3Γ of the respective hyperfine transition. In the end, we analyze the Zeeman structures and magnetic g factors with and without J mixing of the <inline-formula><tex-math id="M239">\begin{document}$ |X, \mathrm{ }N=1, -\rangle $\end{document}</tex-math><alternatives><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="16-20210522_M239.jpg"/><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="16-20210522_M239.png"/></alternatives></inline-formula> state to undercover more information about the magneto-optical trapping. Our work here not only demonstrates the feasibility of laser cooling and trapping of CaH, but also illuminates the studies related to spectral analysis in astrophysics, ultracold molecular collisions and fundamental physics such as exploring the fundamental symmetry violations.

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Electronic, structural and vibrational properties of calcium monohydride

Cited by 3 publications

References 67 publications

Non-Relativistic Electronic-Structure Computation of Neutral and Cationic Systems [Fr₂, Fr–AEM⁺ (AEM= Ca, Sr, Ba)]

Non-Relativistic Electronic-Structure Computation of Neutral and Cationic Systems [Fr₂, Fr–AEM⁺ (AEM= Ca, Sr, Ba)]

A Neural Network Potential Energy Surface and Quantum Dynamics Study of Ca(¹S) + H₂(v₀ = 0, j₀ = 0) → CaH + H Reaction

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Electronic, structural and vibrational properties of calcium monohydride

Cited by 3 publications

References 67 publications

Non-Relativistic Electronic-Structure Computation of Neutral and Cationic Systems [Fr2, Fr–AEM+ (AEM= Ca, Sr, Ba)]

Non-Relativistic Electronic-Structure Computation of Neutral and Cationic Systems [Fr2, Fr–AEM+ (AEM= Ca, Sr, Ba)]

A Neural Network Potential Energy Surface and Quantum Dynamics Study of Ca(1S) + H2(v0 = 0, j0 = 0) → CaH + H Reaction

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Non-Relativistic Electronic-Structure Computation of Neutral and Cationic Systems [Fr₂, Fr–AEM⁺ (AEM= Ca, Sr, Ba)]

Non-Relativistic Electronic-Structure Computation of Neutral and Cationic Systems [Fr₂, Fr–AEM⁺ (AEM= Ca, Sr, Ba)]

A Neural Network Potential Energy Surface and Quantum Dynamics Study of Ca(¹S) + H₂(v₀ = 0, j₀ = 0) → CaH + H Reaction