Formation of ultracold ion pairs through long-range Rydberg molecules

Abstract

We propose a new approach to excite ion-pair states of ultracold dimers. The central idea is a two-step process where first long-range Rydberg molecules are formed by photoassociation, which are then driven by stimulated emission towards the ion-pair state, a process bearing features of a photo-induced harpooning reaction. We assess the feasibility of this approach through a detailed experimental and theoretical study on a specific system, p-wave-scattering dominated long-range Rydberg molecules in caesium, and discuss potential applications for the study of strongly correlated plasmas consisting of oppositely charged particles of equal or similar mass.

Heteronuclear long-range Rydberg molecules

“…Here the curves for different values of Ω have very different depths. We note that we have discussed these minima previously in the context of driving transitions to ion-pair states [33]. After solving the Schrödinger equation for the nuclear motion in the calculated Ω-dependent PECs (see next section), we find that the binding energy of the lowest level in the outermost well varies by less than 2 MHz (see wavefunctions and energies of the vibrational levels in We observe that the depth of the outermost well in the calculated PECs increases when (i ) the basis set includes more hydrogenic manifolds above the state of interest and (ii ) the reference state (Eq.…”

“…Assigning other observed molecular resonances, which could originate from states located at shorter internuclear distances, will yield information about the energy dependence of the scattering phases. A full and accurate understanding of the PECs of heteronuclear LRMs is also prerequisite for schemes to probe spatial correlations in ultracold mixtures [25,32] and to form strongly-coupled plasmas with variable mass ratios of oppositely charged particles [33].…”

Photoionization of $nS$ and $nD$ Rydberg atoms of Rb and Cs from the near-infrared to the ultraviolet spectral region

“…Additionally, there have been measurements of the Cooper minimum of atoms in a plasma background [19][20][21]. Meanwhile, shape resonances have been observed in positronium [22] and in atom collisions [23][24][25], and they have been used to form Rydberg molecules [26,27].…”

Electric field-induced wave-packet dynamics and geometrical rearrangement of trilobite Rydberg molecules

“…Their molecular properties such as dipole moments or alignment can be controlled via weak external electric and magnetic fields [30][31][32][33][34][35][36]. Recently, ULRM have been proposed as candidates for the production of ultra-cold negative ions [37,38] and other classes of exotic molecules via ion-pair dressing [39] and Rydberg dressing [40].…”