RadicalPy: A Tool for Spin Dynamics Simulations

Area of Science:

• Covers diverse scientific fields including physics (organic semiconductors, spintronics, quantum computing, solar cells), chemistry (reaction dynamics), and biology (biomimetic systems, quantum biology).

Background:

• Radical pairs are crucial transient intermediates in numerous scientific disciplines.
• Quantitative analysis of radical pair phenomena has been historically limited to specialized groups.
• Existing simulation methods face challenges with accuracy, computational cost, or memory requirements.

Purpose of the Study:

• To develop an intuitive, open-source Python framework for simulating radical pair phenomena.
• To introduce the novel 'kine-quantum' method combining classical, semiclassical, and quantum approaches.
• To provide a versatile tool for research, education, and standardization in spin dynamics simulations.

Main Methods:

• Implementation of classical, semiclassical, and quantum simulation methodologies.
• Development of a radical pair kinetic rate equation solver and Monte Carlo-based spin dephasing estimators.
• Introduction of the 'kine-quantum' method to overcome memory limitations of purely quantum methods while enhancing accuracy.
• Inclusion of wavelength-resolved simulation capabilities for time- and wavelength-dependent magnetic field effects.

Main Results:

• The kine-quantum method achieves higher accuracy with reduced memory footprint compared to traditional quantum methods.
• Demonstrated versatility through model examples including photochemistry, molecular dynamics simulations, protein radical anisotropy, and crystal exciton pairs.
• The framework provides functionalities for molecule database management and estimation of spin-spin interactions.

Conclusions:

• The developed Python framework and kine-quantum method offer a powerful, accessible tool for studying radical pair dynamics.
• The software facilitates accurate, efficient, and wavelength-resolved simulations, advancing spin chemistry research.
• The intuitive and modular design promotes its use as a teaching aid and aims to standardize spin dynamics simulation practices.