Ab initio properties of the ground-state polar and paramagnetic europium-alkali-metal-atom and europium-alkaline-earth-metal-atom molecules

TL;DR

This study uses ab initio methods to investigate the electronic ground-state properties of europium-based polar and paramagnetic molecules, providing data on potential energy, dipole moments, polarizabilities, and dispersion coefficients relevant for quantum simulation.

Contribution

It presents the first comprehensive ab initio calculations of Eu-alkali and Eu-alkaline-earth molecules' properties, including electric and magnetic dipole moments and long-range interactions.

Findings

EuK, EuRb, and EuCs have large electric and magnetic dipole moments.

Potential energy curves and dispersion coefficients are computed for various Eu-containing molecules.

Eu-alkali and Eu-alkaline-earth molecules are promising for ultracold quantum simulations.

Abstract

The properties of the electronic ground state of the polar and paramagnetic europium-$S$-state-atom molecules have been investigated. Ab initio techniques have been applied to compute the potential energy curves for the europium-alkali-metal-atom, Eu$X$ ($X$=Li, Na, K, Rb, Cs), europium-alkaline-earth-metal-atom, Eu$Y$ ($Y$=Be, Mg, Ca, Sr, Ba), and europium-ytterbium, EuYb, molecules in the Born-Oppenheimer approximation for the high-spin electronic ground state. The spin restricted open-shell coupled cluster method restricted to single, double, and noniterative triple excitations, RCCSD(T), was employed and the scalar relativistic effects within the small-core energy-consistent pseudopotentials were included. The permanent electric dipole moments and static electric dipole polarizabilities were computed. The leading long-range coefficients describing the dispersion interaction between atoms at large internuclear distances $C_6$ are also reported. The EuK, EuRb, and EuCs molecules are examples of species possessing both large electric and magnetic dipole moments making them potentially interesting candidates for ultracold many-body quantum simulations when confined in an optical lattice in combined electric and magnetic fields.