Spatial imaging of a novel type of molecular ions

Abstract

Atoms with a highly excited electron, called Rydberg atoms, can form unusual types of molecular bonds [1][2][3][4]. The bond differs from the well known ionic and covalent bonds [5,6] not only by its binding mechanism, but also by its bond length ranging up to several micrometres. Here, we observe a new type of molecular ion based on the interaction between the ionic charge and a flipping induced dipole of a Rydberg atom with a bond length of several micrometres. We measure the vibrational spectrum and spatially resolve the bond length and the angular alignment of the molecule using a high-resolution ion microscope [7]. As a consequence of the large bond length, the molecular dynamics is extremely slow. These results pave the way for future studies of spatio-temporal effects in molecular dynamics, e.g., beyond Born-Oppenheimer physics.

Ultracold ion-atom experiments: cooling, chemistry, and quantum effects

“…The Rydberg blockade takes care that only a single ionic impurity is created (Balewski et al, 2013;Kleinbach et al, 2018). Rydberg atoms can also be coupled to either free or trapped ions (Engel et al, 2018;Ewald et al, 2019;Haze et al, 2019;Deiß et al, 2021;Zuber et al, 2021). These Rydberg atoms have a stronger polarization and provide a strong interaction with the ion.…”

“…However, singling out these two very recent results does not do full justice to the rapid developments in the whole field. Other important examples of breakthroughs include the observation of signatures of s-wave spin dynamics far above the s-wave energy Côté and Simbotin, 2018;, rapid improvements in buffer gas cooling (Haze et al, 2018;Schmidt et al, 2020b;Hirzler et al, 2020a;Dieterle et al, 2021;Trimby et al, 2022), observations of interactions between Rydberg atoms and ions (Engel et al, 2018;Ewald et al, 2019;Haze et al, 2019;Deiß et al, 2021;Zuber et al, 2021), the accurate experimental breakdown of cold chemistry reactions paths in ion-atom mixtures (da Silva Jr et al, 2017;Ben-shlomi et al, 2020;Mohammadi et al, 2021;Ben-shlomi et al, 2021), quantum logic spectroscopy of ion-atom chemistry (Katz et al, 2022) and recently the observation of interactions between atomic Feshbach dimers and trapped ions (Hirzler et al, 2020b(Hirzler et al, , 2022, just to mention a few.…”

Nonadiabatic decay of metastable states on coupled linear potentials

“…Potential wells emerging from two intersecting diabatic potentials with opposite slopes, coupled by an (approximately) constant interaction, are abound in physics and chemistry [1,2]. Examples include atom traps in optical lattices with Raman couplings [3][4][5][6], confinement of Bose-Einstein condensates on RF-dressed magnetic potentials with spin-dependent slopes [7][8][9][10], atom interferometry in RF-dressed magnetic guiding potentials [11][12][13][14], dressed atom-RF-field states in cavity-QED systems [15,16], Rydberg atoms in external fields [17][18][19], intersecting potential energy curves with radially dependent adiabatic electronic states in Rydberg-Rydberg [20,21], Rydberg-ground [20,22] and Rydberg-ion [23][24][25][26] molecules, and a host of conical intersections in quantum chemistry [27][28][29][30]. If the slopes of the diabatic potentials have opposite signs, the upper adiabatic potential surface exhibits a potential well, and the classical motion in this well is a bound, periodic oscillation about the avoided crossing.…”

“…If the slopes of the diabatic potentials have opposite signs, the upper adiabatic potential surface exhibits a potential well, and the classical motion in this well is a bound, periodic oscillation about the avoided crossing. Such cases are common in molecular physics, as in Rydberg-ion molecules [23][24][25][26], and in atom trapping [31][32][33]. The semi-classical Landau-Zener (LZ) tunneling equation [34,35] has sometimes been applied to estimate nonadiabatic decay rates of quantum states in such adiabatic-potential wells.…”

Probing ultracold gases using photoionization fine structure

“…The full potential of this method will unfold in future work with the inclusion of spin-orbit coupling effects and multiple scattering off of several perturber atoms. Future extensions of our theory will permit to investigate the emerging diverse settings of Rydberg interacting systems, such as Rydberg-Rydberg [34][35][36][37] and, very recently, Rydberg-ion, bound states [38][39][40], using the fine structure of photoionization and its variants as a sensitive probe.…”