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Park E, Park J, Kim I, Kim J, Seo W, Yadav RK, Kim J. Quantum chemical calculations of electron affinities of alkaline earth metal atoms (Ca, Sr, Ba, and Ra). J Chem Phys 2024; 160:224307. [PMID: 38856063 DOI: 10.1063/5.0207127] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2024] [Accepted: 05/23/2024] [Indexed: 06/11/2024] Open
Abstract
We performed high-level ab initio quantum chemical calculations, incorporating higher-order excitations, spin-orbit coupling (SOC), and the Gaunt interaction, to calculate the electron affinities (EAs) of alkaline earth (AE) metal atoms (Ca, Sr, Ba, and Ra), which are notably small. The coupled-cluster singles and doubles with perturbative triples [CCSD(T)] method is insufficient to accurately calculate the EAs of AE metal atoms. Higher-order excitations proved crucial, with the coupled-cluster singles, doubles, and triples with perturbative quadruples [CCSDT(2)Q] method effectively capturing dynamic electron correlation effects. The contributions of SOC (ΔESOs) to the EAs calculated using the multireference configuration interaction method with the Davidson correction, including SOC, positively enhance the EAs; however, these contributions are overestimated. The Dirac-Hartree-Fock (DHF)-CCSD(T) method addresses this overestimation and provides reasonable values for ΔESO (ΔESO-D). Employing additional sets of diffuse and core-valence correlation basis sets is critical for accurately calculating the EAs of AE metal atoms. The contributions of the Gaunt interaction (ΔEGaunt) to the EAs of AE metal atoms are negligible. Notably, the CCSDT(2)Q with the complete basis set limit + ΔESO-D + ΔEGaunt produced EA values for Ca, Sr, and Ba that closely aligned with experimental data and achieved accuracy exceeding the chemical accuracy. Based on our findings, the accurately proposed EA for Ra is 9.88 kJ/mol.
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Affiliation(s)
- Eunji Park
- Department of Chemistry, The Catholic University of Korea, Bucheon 14662, Republic of Korea
| | - Jeongmin Park
- Department of Chemistry, The Catholic University of Korea, Bucheon 14662, Republic of Korea
| | - Ingyeong Kim
- Department of Chemistry, The Catholic University of Korea, Bucheon 14662, Republic of Korea
| | - Jungyoon Kim
- Department of Chemistry, The Catholic University of Korea, Bucheon 14662, Republic of Korea
| | - Wonil Seo
- Department of Chemistry, The Catholic University of Korea, Bucheon 14662, Republic of Korea
| | - Rajesh K Yadav
- Department of Chemistry and Environmental Science, Madan Mohan Malaviya University of Technology, Gorakhpur 273010, U.P., India
| | - Joonghan Kim
- Department of Chemistry, The Catholic University of Korea, Bucheon 14662, Republic of Korea
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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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Moussa A, El-Kork N, Zeid I, Salem E, Korek M. Laser Cooling with an Intermediate State and Electronic Structure Studies of the Molecules CaCs and CaNa. ACS OMEGA 2022; 7:18577-18596. [PMID: 35694530 PMCID: PMC9178733 DOI: 10.1021/acsomega.2c01224] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/02/2022] [Accepted: 05/09/2022] [Indexed: 05/19/2023]
Abstract
The ground and excited electronic states of the diatomic molecules CaCs and CaNa have been investigated by implementing the ab initio CASSCF/(MRCI + Q) calculation. The potential energy curves of the doublet and quartet electronic low energy states in the representation 2s+1Λ(±) have been determined for the two considered molecules, in addition to the spectroscopic constants T e, ωe, B e, R e, and the values of the dipole moment μe and the dissociation energy D e. The determination of vibrational constants E v, B v, D v, and the turning points R min and R max up to the vibrational level v = 100 was possible with the use of the canonical functions schemes. Additionally, the transition and the static dipole moments curves, Einstein coefficients, the spontaneous radiative lifetime, the emission oscillator strength, and the Franck-Condon factors are computed. These calculations showed that the molecule CaCs is a good candidate for Doppler laser cooling with an intermediate state. A "four laser" cooling scheme is presented, along with the values of Doppler limit temperature T D = 55.9 μK and the recoil temperature T r = 132 nK. These results should provide a good reference for experimental spectroscopic and ultra-cold molecular physics studies.
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Affiliation(s)
- Amal Moussa
- Faculty
of Science, Beirut Arab University, P.O. Box 11-5020, Riad El Solh, Beirut 1107 2809, Lebanon
| | - Nayla El-Kork
- Department
of Physics, Khalifa University, P.O. Box 127788, Abu Dhabi 51133, United Arab Emirates
- Space
and Planetary Science Center, Khalifa University, Abu Dhabi 51133, United Arab Emirates
| | - Israa Zeid
- Faculty
of Science, Beirut Arab University, P.O. Box 11-5020, Riad El Solh, Beirut 1107 2809, Lebanon
| | - Ehab Salem
- Faculty
of Science, Beirut Arab University, P.O. Box 11-5020, Riad El Solh, Beirut 1107 2809, Lebanon
| | - Mahmoud Korek
- Faculty
of Science, Beirut Arab University, P.O. Box 11-5020, Riad El Solh, Beirut 1107 2809, Lebanon
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Koput J. Ground-state potential energy functions and vibration-rotation energy levels of beryllium lithium and its cation. J Comput Chem 2022; 43:491-498. [PMID: 35019160 DOI: 10.1002/jcc.26809] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2021] [Revised: 12/29/2021] [Accepted: 12/30/2021] [Indexed: 11/08/2022]
Abstract
The accurate ground-state potential energy functions of the beryllium lithium dimer, BeLi, and its cation, BeLi+ , have been determined from ab initio calculations using the multi-reference averaged coupled-pair functional (MR-ACPF) method in conjunction with the correlation-consistent core-valence basis sets up to septuple-zeta quality. The importance of the electron correlation beyond the MR-ACPF level of approximation, scalar relativistic, and adiabatic effects was discussed. For BeLi+ , the similar calculation was performed using the single-reference coupled-cluster method, up to the CCSDTQ level of approximation. The vibration-rotation energy levels of the two species were predicted to near the "spectroscopic" accuracy. Strangely enough, the predicted vibrational term values do not compare well with the recent experimental data for either BeLi or BeLi+ , with discrepancies reaching as much as 20-60 cm-1 for highly excited vibrational levels.
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Affiliation(s)
- Jacek Koput
- Department of Chemistry, Adam Mickiewicz University, Poznań, Poland
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Persinger TD, Han J, Heaven MC. Electronic Spectroscopy and Photoionization of LiBe. J Phys Chem A 2021; 125:8274-8281. [PMID: 34520195 DOI: 10.1021/acs.jpca.1c07014] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
LiBe has been the subject of several theoretical investigations and one spectroscopic study. Initially, these efforts were motivated by interest in the intermetallic bond. More recent work has explored the potential for producing LiBe and LiBe+ at ultracold temperatures. In the present study, we have advanced the spectroscopic characterization of several electronic states of LiBe and the ground state of LiBe+. For the neutral molecule, the 12Π, 22Σ+, 32Σ+, and 42Π(3d) states were observed for the first time. Data for the 22Σ+-X2Σ+ transition support a theoretical prediction that this band system is suitable for direct laser cooling. Photoelectron spectroscopy has been used to determine the ionization energy of LiBe and map the low-energy vibrational levels of LiBe+ X1Σ+. Overall, the results validate the predictions of high-level quantum chemistry calculations for both LiBe and LiBe+.
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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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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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Liu X, Meijer G, Pérez-Ríos J. A data-driven approach to determine dipole moments of diatomic molecules. Phys Chem Chem Phys 2020; 22:24191-24200. [PMID: 33147314 DOI: 10.1039/d0cp03810e] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
We present a data-driven approach for the prediction of the electric dipole moment of diatomic molecules, which is one of the most relevant molecular properties. In particular, we apply Gaussian process regression to a novel dataset to show that dipole moments of diatomic molecules can be learned, and hence predicted, with a relative error ⪅5%. The dataset contains the dipole moment of 162 diatomic molecules, the most exhaustive and unbiased dataset of dipole moments up to date. Our findings show that the dipole moment of diatomic molecules depends on atomic properties of the constituents atoms: electron affinity and ionization potential, as well as on (a feature related to) the first derivative of the electronic kinetic energy at the equilibrium distance.
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Affiliation(s)
- Xiangyue Liu
- Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, 14195 Berlin, Germany.
| | - Gerard Meijer
- Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, 14195 Berlin, Germany.
| | - Jesús Pérez-Ríos
- Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, 14195 Berlin, Germany.
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Li S, Wan MJ, Chen SJ, Jin YY, Zhang CZ, Chen P, Wang N. An ab initio investigation on the low-lying electronic states of NaMg. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2018; 202:368-375. [PMID: 29803975 DOI: 10.1016/j.saa.2018.05.043] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/12/2018] [Revised: 05/02/2018] [Accepted: 05/09/2018] [Indexed: 06/08/2023]
Abstract
Theoretical investigations for NaMg have been performed on the icMRCI + Q level employing basis set of quintuple-ζ quality with corrections of core-valence correlation and scalar relativistic effect. The geometrical parameters, potential energy curves, vibrational energy levels, spectroscopic constants for the eight Λ-S states, with respect to the lowest four dissociation limits, are investigated. Through the spin-orbit coupling effect, these states split into fourteen Ω states. The permanent dipole moments, transition dipole moments, Einstein emission coefficients, radiative lifetimes and Franck-Condon factors for all Ω states are studied. The feasibility of performing laser cooling of NaMg has also been discussed. Our predictive results are anticipated to serve as guidelines for further researches on NaMg.
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Affiliation(s)
- Song Li
- School of Physics and Optoelectronic Engineering, Yangtze University, Jingzhou, China.
| | - Ming-Jie Wan
- Computational Physics Key Laboratory of Sichuan Province, Yibin University, Yibin, China
| | - Shan-Jun Chen
- School of Physics and Optoelectronic Engineering, Yangtze University, Jingzhou, China
| | - Yuan-Yuan Jin
- School of Physics and Optoelectronic Engineering, Yangtze University, Jingzhou, China
| | - Chuan-Zhao Zhang
- School of Physics and Optoelectronic Engineering, Yangtze University, Jingzhou, China
| | - Peng Chen
- School of Physics and Optoelectronic Engineering, Yangtze University, Jingzhou, China
| | - Ning Wang
- School of Physics and Optoelectronic Engineering, Yangtze University, Jingzhou, China
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Zeid I, Atallah T, Kontar S, Chmaisani W, El-Kork N, Korek M. Theoretical electronic structure of the molecules SrX (X = Li, Na, K) toward laser cooling study. COMPUT THEOR CHEM 2018. [DOI: 10.1016/j.comptc.2018.01.013] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Ciamei A, Szczepkowski J, Bayerle A, Barbé V, Reichsöllner L, Tzanova SM, Chen CC, Pasquiou B, Grochola A, Kowalczyk P, Jastrzebski W, Schreck F. The RbSr2Σ+ground state investigatedviaspectroscopy of hot and ultracold molecules. Phys Chem Chem Phys 2018; 20:26221-26240. [DOI: 10.1039/c8cp03919d] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A synthesis of information fromab initiocalculations and molecular spectroscopy allows a comprehensive description of the RbSr2Σ+ground-state potential.
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Fedorov DA, Barnes DK, Varganov SA. Ab initio calculations of spectroscopic constants and vibrational state lifetimes of diatomic alkali-alkaline-earth cations. J Chem Phys 2017; 147:124304. [PMID: 28964028 DOI: 10.1063/1.4986818] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
We investigate the lifetimes of vibrational states of diatomic alkali-alkaline-earth cations to determine their suitability for ultracold experiments where long decoherence time and controllability by an external electric field are desirable. The potential energy and permanent dipole moment curves for the ground electronic states of LiBe+, LiMg+, NaBe+, and NaMg+ are obtained using the coupled cluster with singles doubles and triples and multireference configuration interaction methods in combination with large all-electron cc-pCVQZ and aug-cc-pCV5Z basis sets. The energies and wave functions of all vibrational states are obtained by solving the Schrödinger equation for nuclei with the B-spline basis set method. To predict the lifetimes of vibrational states, the transition dipole moments, as well as the Einstein coefficients describing spontaneous emission, and the stimulated absorption and emission induced by black body radiation are calculated. Surprisingly, in all studied ions, the lifetimes of the highest excited vibrational states are similar to the lifetimes of the ground vibrational states indicating that highly vibrationally excited ions could be useful for the ultracold experiments requiring long decoherence time.
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Affiliation(s)
- Dmitry A Fedorov
- Department of Chemistry, University of Nevada, Reno, 1664 N. Virginia St., Reno, Nevada 89557-0216, USA
| | - Dustin K Barnes
- Department of Chemistry, University of Nevada, Reno, 1664 N. Virginia St., Reno, Nevada 89557-0216, USA
| | - Sergey A Varganov
- Department of Chemistry, University of Nevada, Reno, 1664 N. Virginia St., Reno, Nevada 89557-0216, USA
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Houalla D, Chmaisani W, El-Kork N, Korek M. Electronic structure calculation of the MgAlk (Alk = K, Rb, Cs) molecules for laser cooling experiments. COMPUT THEOR CHEM 2017. [DOI: 10.1016/j.comptc.2017.03.009] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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