Role of Spin-Dependent Interactions in Chemical Reactions and Molecular Physics
Loading...
Authors
Dergachev, Vsevolod
Issue Date
2021
Type
Dissertation
Language
Keywords
Alternative Title
Abstract
This work describes development of theoretical models for applications where spin-dependent interactions play a key role. Specifically, we focus on the spin-orbit and hyperfine interactions in atoms and molecules, which are important for applications in photochemistry, photophysics, materials science, quantum sensing, and quantum computing. In the first part of this work, we discuss development and application of the nonadiabatic statistical theory (NAST) to predict kinetics of spin-forbidden chemical reactions, intersystem crossings and spin-crossovers. We describe the newly developed NAST software package and its capabilities. The package predicts the microcanonical and canonical rate constants for the nonadiabatic spin-orbit coupling driven and traditional adiabatic unimolecular reactions. In addition, the NAST package can calculate the probabilities and rate constants for transitions between individual MS components of the spin multiplets, and process the results of electronic structure calculations to generate the necessary input data for the rate calculations. The second part of this work is motivated by the proposed applications of ultracold atoms in the quantum information science. The ultracold alkali atoms trapped in inert parahydrogen matrix have been shown to possess long coherence times between the hyperfine states |�"� F,m_F ⟩�"�. The long coherence times make these atoms promising candidates for spin-based qubits and quantum sensors. This coherence is limited by interaction between the electron spin of the alkali metal atom and the host matrix. To explain the experimental coherence times of 39K, 85Rb, 87Rb, and 133Cs atoms, we develop a model of inhomogeneous broadening of the transitions between the |�"� F,m_F ⟩�"� states due to the anisotropic hyperfine interaction between the metal and the host matrix. In the third part of this work, we model the effect of extreme variations in the speed of light on the electronic and atomic structures of small molecules. This part of work is motivated by the theories beyond the Standard Model of physics that treat the fundamental constants as dynamic entities.