Accurate Methods for Ultracold Reactions with Product Quantum State Resolution

University Of Nevada Las Vegas, Las Vegas NV

Investigators

Abstract

Ultracold molecules offer unprecedented opportunities for high-resolution molecular spectroscopy, quantum information processing, and controlled interrogation of molecular events, including chemical reactivity in the ultimate quantum regime. A quantitative description of their collisions and interactions requires a quantum mechanical approach, but it is computationally challenging for many molecules of interest to current cooling and trapping experiments. The primary difficulty is the proliferation in the number of quantum states and degrees of freedom to be included in the calculations and the sensitivity of results to both short-range and long-range intermolecular forces. This work will develop new theoretical and computational tools that go beyond existing models for the treatment of chemical reactions at temperatures below 1 degree Kelvin. It will significantly enhance theoretical capabilities for the description of chemical reactions at cold and ultracold temperatures and provide an efficient tool for quantized studies of chemical reactions at low temperatures. The proposed research transcends disciplinary boundaries, and the computational algorithms developed will also be equally applicable to molecular processes in diverse environments ranging from atmospheric chemistry to astrophysics. Funding of this project will also contribute to future workforce development in Science and Technology. This project deals with the development of accurate and efficient methods to study chemical reactions and energy transfer in cold molecular collisions. The full Close-Coupling (CC) method will continue to be developed and optimized. A hybrid method that uses full CC at short range and Multi-Channel Quantum Defect Theory (MQDT) at long range will also be developed and benchmarked. These methods will be applied to a number of reactions including F + H2 and OH + H. In addition, the PI will explore the importance of the geometric phase in chemical reaction dynamics using the O + OH reaction at the ultracold limit as a illustrative case.