arXiv subjects

Pavel Soldán

Publications and source records attributed to Pavel Soldán.

3 recordsLinked to original sources

arXiv2025

Spin-polarized alkali-metal trimers revisited

Homonuclear spin-polarized alkali-metal trimers in their lowest-lying electronic state are investigated theoretically. Their equilibrium geometries and binding energies are determined with the state-of-the-art quantum chemical methods at three levels of approximation. The equilibrium geometries obtained $R_{\rm eq}({\rm Li}_3) = 3.100$ Å, $R_{\rm eq}({\rm Na}_3) = 4.353$ Å, $R_{\rm eq}({\rm K}_3) = 4.996$ Å, $R_{\rm eq}({\rm Rb}_3) = 5.391$ Å, and $R_{\rm eq}({\rm Cs}_3) = 5.730$ Å are compared to the other theoretical results and also with the very recent experimental results obtained through the laser-induced Coulomb explosion. Further theoretical studies are proposed, which could help with better interpretation of the experimental results for the sodium and cesium trimers.

physics.chem-ph↗

arXiv2009

Prospects for sympathetic cooling of polar molecules: NH with alkali-metal and alkaline-earth atoms - a new hope

We explore the potential energy surfaces for NH molecules interacting with alkali-metal and alkaline-earth atoms using highly correlated ab-initio electronic structure calculations. The surfaces for interaction with alkali-metal atoms have deep wells dominated by covalent forces. The resulting strong anisotropies will produce strongly inelastic collisions. The surfaces for interaction with alkaline-earth atoms have shallower wells that are dominated by induction and dispersion forces. For Be and Mg the anisotropy is small compared to the rotational constant of NH, so that collisions will be relatively weakly inelastic. Be and Mg are thus promising coolants for sympathetic cooling of NH to the ultracold regime.

physics.chem-ph↗

arXiv2006

Cold collisions of OH and Rb. I: the free collision

We have calculated elastic and state-resolved inelastic cross sections for cold and ultracold collisions in the Rb($^1 S$) + OH($^2 Π_{3/2}$) system, including fine-structure and hyperfine effects. We have developed a new set of five potential energy surfaces for Rb-OH($^2 Π$) from high-level {\em ab initio} electronic structure calculations, which exhibit conical intersections between covalent and ion-pair states. The surfaces are transformed to a quasidiabatic representation. The collision problem is expanded in a set of channels suitable for handling the system in the presence of electric and/or magnetic fields, although we consider the zero-field limit in this work. Because of the large number of scattering channels involved, we propose and make use of suitable approximations. To account for the hyperfine structure of both collision partners in the short-range region we develop a frame-transformation procedure which includes most of the hyperfine Hamiltonian. Scattering cross sections on the order of $10^{-13}$ cm$^2$ are predicted for temperatures typical of Stark decelerators. We also conclude that spin orientation of the partners is completely disrupted during the collision. Implications for both sympathetic cooling of OH molecules in an environment of ultracold Rb atoms and experimental observability of the collisions are discussed.

physics.atom-ph↗