Predicting Kinetics of Spin-Dependent Reactions in an External Magnetic Field with Nonadiabatic Statistical Theory

This work provides a broad theoretical exploration of the kinetics of spin-dependent reactions under the influence of an external magnetic field. We tackle the complexities of computational modeling of reactions characterized by non-radiative transitions between electronic states with different spin multiplicities in a range of magnetic fields using the nonadiabatic statistical theory (NAST). The new computational methodology is applied to the spin-forbidden isomerization of the Ni(dpp)Cl₂ complex, revealing a notable increase in the rate constants under strong field conditions. We also discuss different theoretical approaches for calculating spin-orbit coupling (SOC) that mediates transitions between electronic states with different spin multiplicities. The introduced effective, intermediate, and Ms-specific SOC approaches are employed to calculate the rate constants of spin transitions in the active site model of the protein rubredoxin. The magnetic field effects and new approaches for calculating SOC have been implemented in the NAST software package, which uses results of electronic structure calculations to predict the transition probabilities and rate constants of spin-forbidden reactions, intersystem crossings, and spin crossovers. This comprehensive investigation integrates computational and theoretical approaches, offering a detailed understanding of spin-dependent processes and their modulation by external factors, which is invaluable for both computational chemists and experimentalists in advancing the field of spin chemistry. In the final section of this work, we investigate how structural and environmental factors influence the thermal relaxation mechanisms of spirooxazine-based photochromes, aiming to design more efficient photochromic materials. Furthermore, we demonstrate that the coordination of a spirooxazine ligand to a copper(II) complex with potential long decoherence times provides different profiles for hyperfine coupling constant and isotropic g-value upon photoisomerization. Therefore, control of spin states of this copper(II) complex can be achieved through the photoisomerization of the spirooxazine ligand.

Name thesis:degree_name

Doctor of Philosophy

Level thesis:degree_level

Doctorate Degree

Year dc:date.issued

2024

Author dc:creator

• Rooein, Mitra

Advisor dc:contributor.advisor

• Varganov, Sergey

Language dc:language.iso

en_US, English

Repository record dc:identifier.uri

https://scholarwolf.unr.edu/handle/11714/11149

OAI identifier oai:identifier

oai:scholarwolf.unr.edu:11714/11149