The ground-state interaction potential of ytterbium dimer is investigated at eXact 2-component core-correlated CCSD(T) level of {\it ab initio} theory in the complete basis set limit with extensive augmentation by diffuse functions. For the basis set of double- $\zeta$ quality, the comparison is made with the four-component relativistic finite-nuclei CCSD(T) calculations to identify the contraction of the dimer bond length as the main unrecoverable deficiency of the scalar-relativistic approximation. Empirical constraint on the number of bound vibrational energy levels of the $^{174}$ Yb $_2$ dimer is accounted for by employing the model semianalytical potential function [M. Borkowski et al. Phys. Rev. A {\bf 96}, 063405 (2017)] containing the scale and shift parameters. Using the best {\it ab initio} data as its short-range part, we estimated the equilibrium parameters of Yb $_2$ dimer as $R_e \in [4.45, 4.55]$ A and $D_e = 745 \pm 10$ cm $^{-1}$ . Furthermore, we demonstrated that the model potential provides an accurate and flexible reference for future research in constraining short-range gravity-like forces by ultracold atomic spectroscopy.The ground-state interaction potential of ytterbium dimer is investigated at eXact 2-component core-correlated CCSD(T) level of {\it ab initio} theory in the complete basis set limit with extensive augmentation by diffuse functions. For the basis set of double-$\zeta$ quality, the comparison is made with the four-component relativistic finite-nuclei CCSD(T) calculations to identify the contraction of the dimer bond length as the main unrecoverable deficiency of the scalar-relativistic approximation. Empirical constraint on the number of bound vibrational energy levels of the $^{174}$Yb$_2$ dimer is accounted for by employing the model semianalytical potential function [M. Borkowski et al. Phys. Rev. A {\bf 96}, 063405 (2017)] containing the scale and shift parameters. Using the best {\it ab initio} data as its short-range part, we estimated the equilibrium parameters of Yb$_2$ dimer as $R_e \in [4.45, 4.55]$ A and $D_e = 745 \pm 10$ cm$^{-1}$. Furthermore, we demonstrated that the model potential provides an accurate and flexible reference for future research in constraining short-range gravity-like forces by ultracold atomic spectroscopy.

Jul 21, 20210 citations

Non-adiabatic quantum dynamics of the ultracold Li+LiNa→ Li2+Na chemical reaction

Brian K. Kendrick, Mingzhe Li, H. Li +3 more

Synopsis We report non-adiabatic dynamics of the Li+LiNa→Li2+Na chemical reaction at cold and ultracold temperatures employing accurate ab initio electronic potential energy surfaces in a quantum dynamics formulation employing a diabatic representation. Results are compared against those from a single adiabatic ground state potential energy surface and a universal model based on the long-range interaction potential. We discuss signatures of non-universal behavior in the total rate coefficients as well as strong non-adiabatic effects in the state-to-state rotationally resolved rate coefficients.Synopsis We report non-adiabatic dynamics of the Li+LiNa→Li2+Na chemical reaction at cold and ultracold temperatures employing accurate ab initio electronic potential energy surfaces in a quantum dynamics formulation employing a diabatic representation. Results are compared against those from a single adiabatic ground state potential energy surface and a universal model based on the long-range interaction potential. We discuss signatures of non-universal behavior in the total rate coefficients as well as strong non-adiabatic effects in the state-to-state rotationally resolved rate coefficients.

Journal of Physics Conference SeriesJan 1, 20202 citations

Low-energy He-He interactions with phenomenological potentials

R. F. Bishop, H. B. Ghassib, Michael R. Strayer

Journal of Low Temperature PhysicsMar 1, 197748 citations

Ab-Initio Approach to the Many-Electron Problem

Alexander Quandt

Springer eBooksDec 8, 20071 citation

Determination of the Hubbard model parameters by using the unrestricted Hartree–Fock solutions, and improvement of their energies

Daisuke Yamaki, Koji Yasuda, Kizashi Yamaguchi

Abstract A strategy is proposed to determine parameters in model Hamiltonians from the difference of the density matrices calculated by ab initio methods. As an example, the parameters of the two‐site Hubbard model are determined. The parameters t and U are explicitly expressed in terms of the energy difference and the difference of the expectation values of the spin operator 〈S2〉 between two unrestricted Hartree–Fock (UHF) solutions. By using this relation and the exact energy formulas of the model Hamiltonian the energies of the ground and excited states of the ab initio Hamiltonian are estimated. This energy estimation scheme is applied to H2 and Li2 molecules and the results are in reasonable agreement with those of the full configuration‐interaction method. The errors of our estimation are also discussed and evaluated by using a modified Hubbard model. © 2005 Wiley Periodicals, Inc. Int J Quantum Chem, 2005Abstract A strategy is proposed to determine parameters in model Hamiltonians from the difference of the density matrices calculated by ab initio methods. As an example, the parameters of the two‐site Hubbard model are determined. The parameters t and U are explicitly expressed in terms of the energy difference and the difference of the expectation values of the spin operator 〈S2〉 between two unrestricted Hartree–Fock (UHF) solutions. By using this relation and the exact energy formulas of the model Hamiltonian the energies of the ground and excited states of the ab initio Hamiltonian are estimated. This energy estimation scheme is applied to H2 and Li2 molecules and the results are in reasonable agreement with those of the full configuration‐interaction method. The errors of our estimation are also discussed and evaluated by using a modified Hubbard model. © 2005 Wiley Periodicals, Inc. Int J Quantum Chem, 2005

International Journal of Quantum ChemistryJan 1, 20050 citations

Ab initio Yb

_2

ground state potential revisited

\zeta

quality, the comparison is made with the four-component relativistic finite-nuclei CCSD(T) calculations to identify the contraction of the dimer bond length as the main unrecoverable deficiency of the scalar-relativistic approximation. Empirical constraint on the number of bound vibrational energy levels of the

^{174}

_2

dimer is accounted for by employing the model semianalytical potential function [M. Borkowski et al. Phys. Rev. A {\bf 96}, 063405 (2017)] containing the scale and shift parameters. Using the best {\it ab initio} data as its short-range part, we estimated the equilibrium parameters of Yb

_2

dimer as

R_e \in [4.45, 4.55]

A and

D_e = 745 \pm 10

^{-1}

. Furthermore, we demonstrated that the model potential provides an accurate and flexible reference for future research in constraining short-range gravity-like forces by ultracold atomic spectroscopy.