Finite-size corrections in simulation of dipolar fluids

Area of Science:

• Statistical Mechanics
• Computational Physics
• Soft Matter Physics

Background:

• Dipolar fluids exhibit complex behavior influenced by particle interactions and system size.
• Accurate calculation of correlation functions is vital for understanding fluid properties.
• Finite-size effects in simulations can introduce significant deviations from theoretical predictions.

Purpose of the Study:

• To investigate and quantify finite-size corrections in Monte Carlo simulations of dipolar fluids.
• To analyze the impact of particle number and system size on pair distribution functions.
• To assess the validity of existing theoretical predictions for finite-size effects in dipolar systems.

Main Methods:

• Performing Monte Carlo simulations for dipolar fluids with varying particle numbers (N = 100-4000).
• Accumulating non-spherically symmetric pair distribution functions (g(r,Ω)) using projections onto rotational invariants (gmnl(r)).
• Comparing simulation data with theoretical predictions for finite-size corrections.

Main Results:

• Observed N dependence of gmnl(r) agrees well with theoretical predictions for explicit and implicit finite-size corrections.
• Implicit corrections, arising from particle-image interactions, dominate in strongly dipolar fluids.
• Simulation data can be precisely corrected, enabling derivation of exact correlation functions even for small system sizes (N ≈ 100).
• Discrepancies were found with established literature predictions concerning the 1/N dependence of gmnl(r) when dielectric discontinuity is present.

Conclusions:

• Finite-size corrections are accurately captured by theoretical models, particularly implicit corrections in strongly dipolar fluids.
• Precise data correction allows for the derivation of exact correlation functions from simulations of moderate size.
• Existing theoretical predictions for finite-size effects may require revision, especially under conditions of dielectric discontinuity.