Isobaric molecular dynamics simulations of hard sphere systems

Area of Science:

• Computational physics
• Molecular dynamics simulations

Background:

• Simulating molecular dynamics in the isobaric isoenthalpic (NPH) ensemble is computationally challenging.
• Existing methods for hard sphere systems require adaptations for non-constant particle velocities between collisions.

Purpose of the Study:

• To implement and validate an efficient Andersen algorithm for hard sphere molecular dynamics in the NPH ensemble.
• To extend the algorithm for NPT ensemble simulations of hard sphere systems.

Main Methods:

• Adaptation of the Andersen algorithm for hard spheres in the NPH ensemble.
• Development of an efficient method to handle particle velocities between collisions.
• Extension to the NPT ensemble via ad hoc velocity rescaling.

Main Results:

• The implemented algorithm efficiently simulates hard sphere systems in the NPH ensemble.
• The method accurately captures structural, thermodynamic, and transport properties.
• The extension to the NPT ensemble is validated through comparison with NVE simulations.

Conclusions:

• The developed Andersen algorithm provides an accurate and efficient approach for NPH and NPT ensemble simulations of hard sphere systems.
• This work offers a valuable tool for studying the behavior of dense fluids and related systems.