Definitions of local density in density-dependent potentials for mixtures

Area of Science:

• Computational Materials Science
• Statistical Mechanics
• Condensed Matter Physics

Background:

• Density-dependent potentials offer computational efficiency for modeling many-body effects in materials simulations.
• Applying these potentials to multicomponent systems necessitates a robust definition of total local particle density.
• Existing models face challenges in accurately representing diverse particle interactions within heterogeneous systems.

Purpose of the Study:

• To investigate and propose an appropriate definition of total local particle density for multicomponent systems within many-body dissipative particle dynamics.
• To generalize density-dependent potentials for heterogeneous systems, accommodating varied intertype interactions.
• To demonstrate the emergence of phase coexistence phenomena through parameter tuning.

Main Methods:

• Analysis of two distinct definitions for local density in many-body dissipative particle dynamics simulations.
• Redefinition of local density inspired by metal potentials to handle different intertype interactions.
• Generalization of many-body potentials for multicomponent and heterogeneous systems.
• Computational simulations to observe liquid-liquid and liquid-solid coexistence.

Main Results:

• A combined local density definition, incorporating all particle types, yields physically meaningful results across all composition ratios.
• The redefined local density successfully accommodates differing intertype interactions while adhering to Warren's no-go theorem.
• Simulations confirm that tuning interaction parameters can induce liquid-liquid and liquid-solid phase coexistence.

Conclusions:

• The proposed definition of local density is crucial for the accurate application of density-dependent potentials in multicomponent materials simulations.
• This generalized potential framework effectively models heterogeneous systems and predicts emergent phase behaviors.
• The findings provide a pathway for simulating complex phase transitions in multicomponent materials with reduced computational cost.