The Experts below are selected from a list of 7413 Experts worldwide ranked by ideXlab platform
Olivier Dulieu - One of the best experts on this subject based on the ideXlab platform.
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ground state of the polar alkali metal atom strontium molecules potential energy curve and Permanent Dipole moment
Physical Review A, 2010Co-Authors: Romain Guérout, Mireille Aymar, Olivier DulieuAbstract:In this study, we investigate the structure of the polar alkali-Strontium diatomic molecules as possible candidates for the realization of samples of new species of ultracold polar molecules. Using a quantum chemistry approach based on Effective Core Potentials and Core Polarization Potentials, we model these systems as effective three valence electron systems, allowing for calculation of electronic properties with Full Configuration Interaction. The potential curve and the Permanent Dipole moment of the 2 � + ground state are determined as functions of the internuclear distances for LiSr, NaSr, KSr, RbSr, and CsSr molecules. These molecules are found to exhibit a significant Permanent Dipole moment, though smaller than those of the alkali-Rb molecules.
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calculation of accurate Permanent Dipole moments of the lowest σ 1 3 states of heteronuclear alkali dimers using extended basis sets
Journal of Chemical Physics, 2005Co-Authors: Mireille Aymar, Olivier DulieuAbstract:Obtaining ultracold samples of dipolar molecules is a current challenge which requires an accurate knowledge of their electronic properties to guide the ongoing experiments. In this paper, we systematically investigate the ground state and the lowest triplet state of mixed alkali dimers (involving Li, Na, K, Rb, Cs) using a standard quantum chemistry approach based on pseudopotentials for atomic core representation, Gaussian basis sets, and effective terms for core polarization effects. We emphasize on the convergence of the results for Permanent Dipole moments regarding the size of the Gaussian basis set, and we discuss their predicted accuracy by comparing to other theoretical calculations or available experimental values. We also revisit the difficulty to compare computed potential curves among published papers, due to the differences in the modelization of core-core interaction.
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calculation of accurate Permanent Dipole moments of the lowest 1 3 sigma states of heteronuclear alkali dimers using extended basis sets
arXiv: Quantum Physics, 2005Co-Authors: Mireille Aymar, Olivier DulieuAbstract:The obtention of ultracold samples of dipolar molecules is a current challenge which requires an accurate knowledge of their electronic properties to guide the ongoing experiments. In this paper, we systematically investigate the ground state and the lowest triplet state of mixed alkali dimers (involving Li, Na, K, Rb, Cs) using a standard quantum chemistry approach based on pseudopotentials for atomic core representation, gaussian basis sets, and effective terms for core polarization effects. We emphasize on the convergence of the results for Permanent Dipole moments regarding the size of the gaussian basis set, and we discuss their predicted accuracy by comparing to other theoretical calculations or available experimental values. We also revisit the difficulty to compare computed potential curves among published papers, due to the differences in the modelization of core-core interaction.
Sergey A Varganov - One of the best experts on this subject based on the ideXlab platform.
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accurate potential energy Dipole moment curves and lifetimes of vibrational states of heteronuclear alkali dimers
Journal of Chemical Physics, 2014Co-Authors: Dmitry A Fedorov, Andrei Derevianko, Sergey A VarganovAbstract:We calculate the potential energy curves, the Permanent Dipole moment curves, and the lifetimes of the ground and excited vibrational states of the heteronuclear alkali dimers XY (X, Y = Li, Na, K, Rb, Cs) in the X1Σ+ electronic state using the coupled cluster with singles doubles and triples method. All-electron quadruple-ζ basis sets with additional core functions are used for Li and Na, and small-core relativistic effective core potentials with quadruple-ζ quality basis sets are used for K, Rb, and Cs. The inclusion of the coupled cluster non-perturbative triple excitations is shown to be crucial for obtaining the accurate potential energy curves. A large one-electron basis set with additional core functions is needed for the accurate prediction of Permanent Dipole moments. The dissociation energies are overestimated by only 14 cm−1 for LiNa and by no more than 114 cm−1 for the other molecules. The discrepancies between the experimental and calculated harmonic vibrational frequencies are less than 1.7 ...
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accurate potential energy Dipole moment curves and lifetimes of vibrational states of heteronuclear alkali dimers
arXiv: Chemical Physics, 2014Co-Authors: Dmitry A Fedorov, Andrei Derevianko, Sergey A VarganovAbstract:We calculate the potential energy curves, the Permanent Dipole moment curves, and the lifetimes of the ground and excited vibrational states of the heteronuclear alkali dimers XY (X, Y = Li, Na, K, Rb, Cs) in the X1{\Sigma}+ electronic state using the coupled cluster with singles doubles and triples (CCSDT) method. All-electron quadruple-{\zeta} basis sets with additional core functions are used for Li and Na, and small-core relativistic effective core potentials with quadruple-{\zeta} quality basis sets are used for K, Rb and Cs. The inclusion of the coupled cluster non-perturbative triple excitations is shown to be crucial for obtaining the accurate potential energy curves. Large one-electron basis set with additional core functions is needed for the accurate prediction of Permanent Dipole moments. The dissociation energies are overestimated by only 14 cm-1 for LiNa and by no more than 114 cm-1 for the other molecules. The discrepancies between the experimental and calculated harmonic vibrational frequencies are less than 1.7 cm-1, and the discrepancies for the anharmonic correction are less than 0.1 cm-1. We show that correlation between atomic electronegativity differences and Permanent Dipole moment of heteronuclear alkali dimers is not perfect. To obtain the vibrational energies and wave functions the vibrational Schr\"odinger equation is solved with the B-spline basis set method. The transition Dipole moments between all vibrational states, the Einstein coefficients and the lifetimes of the vibrational states are calculated. We analyze the decay rates of the vibrational states in terms of spontaneous emission, and stimulated emission and absorption induced by black body radiation. In all studied heteronuclear alkali dimers the ground vibrational states have much longer lifetimes than any excited states.
Mireille Aymar - One of the best experts on this subject based on the ideXlab platform.
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ground state of the polar alkali metal atom strontium molecules potential energy curve and Permanent Dipole moment
Physical Review A, 2010Co-Authors: Romain Guérout, Mireille Aymar, Olivier DulieuAbstract:In this study, we investigate the structure of the polar alkali-Strontium diatomic molecules as possible candidates for the realization of samples of new species of ultracold polar molecules. Using a quantum chemistry approach based on Effective Core Potentials and Core Polarization Potentials, we model these systems as effective three valence electron systems, allowing for calculation of electronic properties with Full Configuration Interaction. The potential curve and the Permanent Dipole moment of the 2 � + ground state are determined as functions of the internuclear distances for LiSr, NaSr, KSr, RbSr, and CsSr molecules. These molecules are found to exhibit a significant Permanent Dipole moment, though smaller than those of the alkali-Rb molecules.
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calculation of accurate Permanent Dipole moments of the lowest σ 1 3 states of heteronuclear alkali dimers using extended basis sets
Journal of Chemical Physics, 2005Co-Authors: Mireille Aymar, Olivier DulieuAbstract:Obtaining ultracold samples of dipolar molecules is a current challenge which requires an accurate knowledge of their electronic properties to guide the ongoing experiments. In this paper, we systematically investigate the ground state and the lowest triplet state of mixed alkali dimers (involving Li, Na, K, Rb, Cs) using a standard quantum chemistry approach based on pseudopotentials for atomic core representation, Gaussian basis sets, and effective terms for core polarization effects. We emphasize on the convergence of the results for Permanent Dipole moments regarding the size of the Gaussian basis set, and we discuss their predicted accuracy by comparing to other theoretical calculations or available experimental values. We also revisit the difficulty to compare computed potential curves among published papers, due to the differences in the modelization of core-core interaction.
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calculation of accurate Permanent Dipole moments of the lowest 1 3 sigma states of heteronuclear alkali dimers using extended basis sets
arXiv: Quantum Physics, 2005Co-Authors: Mireille Aymar, Olivier DulieuAbstract:The obtention of ultracold samples of dipolar molecules is a current challenge which requires an accurate knowledge of their electronic properties to guide the ongoing experiments. In this paper, we systematically investigate the ground state and the lowest triplet state of mixed alkali dimers (involving Li, Na, K, Rb, Cs) using a standard quantum chemistry approach based on pseudopotentials for atomic core representation, gaussian basis sets, and effective terms for core polarization effects. We emphasize on the convergence of the results for Permanent Dipole moments regarding the size of the gaussian basis set, and we discuss their predicted accuracy by comparing to other theoretical calculations or available experimental values. We also revisit the difficulty to compare computed potential curves among published papers, due to the differences in the modelization of core-core interaction.
Dmitry A Fedorov - One of the best experts on this subject based on the ideXlab platform.
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accurate potential energy Dipole moment curves and lifetimes of vibrational states of heteronuclear alkali dimers
Journal of Chemical Physics, 2014Co-Authors: Dmitry A Fedorov, Andrei Derevianko, Sergey A VarganovAbstract:We calculate the potential energy curves, the Permanent Dipole moment curves, and the lifetimes of the ground and excited vibrational states of the heteronuclear alkali dimers XY (X, Y = Li, Na, K, Rb, Cs) in the X1Σ+ electronic state using the coupled cluster with singles doubles and triples method. All-electron quadruple-ζ basis sets with additional core functions are used for Li and Na, and small-core relativistic effective core potentials with quadruple-ζ quality basis sets are used for K, Rb, and Cs. The inclusion of the coupled cluster non-perturbative triple excitations is shown to be crucial for obtaining the accurate potential energy curves. A large one-electron basis set with additional core functions is needed for the accurate prediction of Permanent Dipole moments. The dissociation energies are overestimated by only 14 cm−1 for LiNa and by no more than 114 cm−1 for the other molecules. The discrepancies between the experimental and calculated harmonic vibrational frequencies are less than 1.7 ...
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accurate potential energy Dipole moment curves and lifetimes of vibrational states of heteronuclear alkali dimers
arXiv: Chemical Physics, 2014Co-Authors: Dmitry A Fedorov, Andrei Derevianko, Sergey A VarganovAbstract:We calculate the potential energy curves, the Permanent Dipole moment curves, and the lifetimes of the ground and excited vibrational states of the heteronuclear alkali dimers XY (X, Y = Li, Na, K, Rb, Cs) in the X1{\Sigma}+ electronic state using the coupled cluster with singles doubles and triples (CCSDT) method. All-electron quadruple-{\zeta} basis sets with additional core functions are used for Li and Na, and small-core relativistic effective core potentials with quadruple-{\zeta} quality basis sets are used for K, Rb and Cs. The inclusion of the coupled cluster non-perturbative triple excitations is shown to be crucial for obtaining the accurate potential energy curves. Large one-electron basis set with additional core functions is needed for the accurate prediction of Permanent Dipole moments. The dissociation energies are overestimated by only 14 cm-1 for LiNa and by no more than 114 cm-1 for the other molecules. The discrepancies between the experimental and calculated harmonic vibrational frequencies are less than 1.7 cm-1, and the discrepancies for the anharmonic correction are less than 0.1 cm-1. We show that correlation between atomic electronegativity differences and Permanent Dipole moment of heteronuclear alkali dimers is not perfect. To obtain the vibrational energies and wave functions the vibrational Schr\"odinger equation is solved with the B-spline basis set method. The transition Dipole moments between all vibrational states, the Einstein coefficients and the lifetimes of the vibrational states are calculated. We analyze the decay rates of the vibrational states in terms of spontaneous emission, and stimulated emission and absorption induced by black body radiation. In all studied heteronuclear alkali dimers the ground vibrational states have much longer lifetimes than any excited states.
Xiaoyu Kuang - One of the best experts on this subject based on the ideXlab platform.
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theoretical study on the ground state of the polar alkali metal barium molecules potential energy curve and Permanent Dipole moment
Journal of Chemical Physics, 2015Co-Authors: Xiaoyu KuangAbstract:In this paper, we systematically investigate the electronic structure for the 2Σ+ ground state of the polar alkali-metal-alkaline-earth-metal molecules BaAlk (Alk = Li, Na, K, Rb, and Cs). Potential energy curves and Permanent Dipole moments (PDMs) are determined using power quantum chemistry complete active space self-consistent field and multi-reference configuration interaction methods. Basic spectroscopic constants are derived from ro-vibrational bound state calculation. From the calculations, it is shown that BaK, BaRb, and BaCs molecules have moderate values of PDM at the equilibrium bond distance (BaK:1.62 D, BaRb:3.32 D, and BaCs:4.02 D). Besides, the equilibrium bond length (4.93 A and 5.19 A) and dissociation energy (0.1825 eV and 0.1817 eV) for the BaRb and BaCs are also obtained.
