Molecular dynamics simulations of dipolar fluids in orientationally ordered phases

Area of Science:

• Computational Physics
• Materials Science
• Chemical Physics

Background:

• Strongly interacting dipoles are known to form orientationally ordered liquid phases.
• Existing computer simulations predominantly utilize the simplified point dipole model.

Purpose of the Study:

• To investigate orientationally ordered phases formed by extended dipoles using molecular dynamics simulations.
• To explore the influence of extended dipole models on liquid phase behavior.

Main Methods:

• Molecular dynamics simulations were employed.
• The potential energy included site-site Lennard-Jones interactions and partial charge electrostatics.
• Simulations covered a range of densities at constant temperature and varied temperatures at constant reduced densities.

Main Results:

• Orientationally ordered phases were observed over a broad density range.
• Extended dipoles exhibited a tendency to form chain-like structures at lower densities.
• The isotropic liquid phase was not observed within the studied density and temperature regimes.

Conclusions:

• Extended dipole models provide a more nuanced understanding of orientationally ordered liquid phases.
• The distinct phase behavior, including chain formation, highlights the limitations of the point dipole approximation.
• Further research can explore phase transitions and properties using these extended models.