Locally adaptive method to define coordination shell.

Area of Science:

• Computational physics
• Materials science
• Chemical physics

Background:

• Defining a particle's coordination shell is crucial for understanding material properties.
• Existing methods often require predefined parameters or assumptions.
• A robust, parameter-free algorithm is needed for accurate coordination shell analysis.

Purpose of the Study:

• To introduce a novel algorithm for defining particle coordination shells.
• To provide a method that relies solely on particle positions.
• To establish a parameter-free approach for coordination shell identification.

Main Methods:

• Developed the Relative Angular Distance (RAD) algorithm based on geometric relationships between particle triplets.
• Applied the RAD algorithm to molecular dynamics simulations of Lennard-Jones particles.
• Simulated crystalline, liquid, and gaseous phases at various temperatures and densities.

Main Results:

• The RAD algorithm successfully defines coordination shells without requiring external parameters.
• RAD-derived coordination shells show strong agreement with radial distribution function cut-offs in crystalline and liquid phases.
• Slightly higher coordination shell values were observed for the gaseous phase using RAD.

Conclusions:

• The RAD algorithm offers a reliable and versatile method for determining coordination shells in diverse particle systems.
• This approach simplifies coordination shell analysis by eliminating the need for pre-set parameters.
• RAD provides accurate results comparable to traditional methods, with potential advantages in specific phases like gases.