## Doctoral Dissertations

12-3-2018

12-2-2018

#### Keywords

Atomic Physics, Quantum Chemistry

Winthrop Smith

Vasili Kharchenko

George Gibson

Physics

Open Access

#### Abstract

Interactions between neutral and ionized atoms are medium-range, and the spiraling nature of these collisions can lead to long interaction times and large cross-sections. The field of ion-neutral interactions is bolstered by methods from atomic physics, which allow us to accurately control and determine the quantum-states of the reactants. Trapping techniques allow us to study these interactions over a large range of energies, in order to observe interesting effects from the ultracold to hot temperature regimes. This control allows us to analyze and determine specific channels for the reaction, allowing for theoretical verification.

The hybrid-trap enables the concentric trapping of a sample of cold atoms and ions. This work discusses our exploration into the controlled reactions in the $\text{Na}-\text{Ca}^+$ system, including measurements of sympathetic cooling and charge-exchange rates which change as a function of energy and molecular state. The quantum-state distributions of Na in our magneto-optical trap is also explored, as well as its agreement and subsequent deviation based on a predictive model. The measurements of reaction rate reveal that there are reaction-energy thresholds in two separate reaction pathways, which can be attributed to either an endothermic reaction pathway or an activation barrier due to quantum-mechanical interactions.

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