# Interactions of benzene, naphthalene, and azulene with alkali-metal and alkaline-earth-metal atoms for ultracold studies

## TL;DR

This paper investigates the intermolecular interactions between aromatic hydrocarbons and ultracold alkali and alkaline-earth atoms using advanced ab initio methods, providing detailed potential energy surfaces for ultracold collision studies.

## Contribution

It presents the first detailed ab initio potential energy surfaces for benzene, naphthalene, and azulene interacting with various ultracold metal atoms, aiding in ultracold molecule research.

## Key findings

- Computed accurate potential energy surfaces for selected aromatic hydrocarbons.
- Analyzed the nature of intermolecular interactions and benchmarked with symmetry-adapted perturbation theory.
- Identified azulene as a promising candidate for ultracold molecule manipulation.

## Abstract

We consider collisional properties of polyatomic aromatic hydrocarbon molecules immersed into ultracold atomic gases and investigate intermolecular interactions of exemplary benzene, naphthalene, and azulene with alkali-metal (Li, Na, K, Rb, Cs) and alkaline-earth-metal (Mg, Ca, Sr, Ba) atoms. We apply the state-of-the-art \textit{ab initio} techniques to compute the potential energy surfaces (PESs). We use the coupled cluster method restricted to single, double, and noniterative triple excitations to reproduce the correlation energy and the small-core energy-consistent pseudopotentials to model the scalar relativistic effects in heavier metal atoms. We also report the leading long-range isotropic and anisotropic dispersion and induction interaction coefficients. The PESs are characterized in detail and the nature of intermolecular interactions is analyzed and benchmarked using symmetry-adapted perturbation theory. The full three-dimensional PESs are provided for selected systems within the atom-bond pairwise additive representation and can be employed in scattering calculations. Presented study of the electronic structure is the first step towards the evaluation of prospects for sympathetic cooling of polyatomic aromatic molecules with ultracold atoms. We suggest azulene, an isomer of naphthalene which possesses a significant permanent electric dipole moment and optical transitions in the visible range, as a promising candidate for electric field manipulation and buffer-gas or sympathetic cooling.