Electronic properties of Francium diatomic compounds and prospects for cold molecule formation

Abstract

In this work we investigate the possibility to create cold Fr$\_2$, RbFr, and CsFr molecules through photoassociation of cold atoms. Potential curves, permanent and transition dipole moments for the Francium dimer and for the RbFr and RbCs molecules are determined for the first time. The Francium atom is modelled as a one valence electron moving in the field of the Fr${}^{+}$ core, which is described by a new pseudopotential with averaged relativistic effects, and including effective core polarization potential. The molecular calculations are performed for both the ionic species Fr$\_2^{+}$, RbFr${}^{+}$, CsFr${}^{+}$ and the corresponding neutral, through the CIPSI quantum chemistry package where we used new extended gaussian basis sets for Rb, Cs, and Fr atoms. As no experimental data is available, we discuss our results by comparison with the Rb$\_2$, Cs$\_2$, and RbCs systems. The dipole moment of CsFr reveals an electron transfer yielding a Cs${}^{+}$Fr${}^{-}$ arrangement, while in all other mixed alkali pairs the electron is transferred towards the lighter species. Finally the perturbative treatment of the spin-orbit coupling at large distances predicts that in contrast with Rb$\_2$ and Cs$\_2$, no double-well excited potential should be present in Fr$\_2$, probably preventing an efficient formation of cold dimers via photoassociation of cold Francium atoms.

References in corpus (6)

• High-precision calculations of dispersion coefficients, static dipole polarizabilities, and atom-wall interaction constants for alkali-metal atoms
• Calculation of accurate permanent dipole moments of the lowest ${}^{1,3}{\Sigma }^{+}$ states of heteronuclear alkali dimers using extended basis sets
• Relativistic many-body calculations of energy levels, hyperfine constants, electric-dipole matrix elements and static polarizabilities for alkali-metal atoms
• Production and state-selective detection of ultracold, ground state RbCs molecules
• High-precision calculations of van der Waals coefficients for heteronuclear alkali-metal dimers
• Many-body and model-potential calculations of low-energy photoionization parameters for Fr

Cited by in corpus (10)

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• Using CIPSI nodes in diffusion Monte Carlo
• Electronic structure of the Magnesium hydride molecular ion
• Diatomic molecules of alkali-metal and alkaline-earth-metal atoms: interaction potentials, dipole moments, and polarizabilities
• Proposal for the formation of ultracold deeply-bound RbSr dipolar molecules by all-optical methods
• Core repulsion effects in alkali trimers
• Relativistic ab initio study on the spectroscopic and radiative properties of the lowest states and modeling of the optical cycles for the LiFr molecule
• Engineering long-range interactions between ultracold atoms with light