Finite-size excess-entropy scaling for simple liquids

Area of Science:

• Computational physics
• Statistical mechanics

Background:

• Computer simulations in physics often exhibit size effects.
• Explicit and implicit size effects arise from fixed particle numbers and periodic boundary conditions, respectively.

Purpose of the Study:

• Investigate size effects on the relationship between reduced self-diffusion coefficient (D*(L)) and two-body excess entropy (s2(L)).
• Analyze the scaling behavior of D*(L) and s2(L) with system size (L).

Main Methods:

• Introduced and validated a finite-size two-body excess entropy integral equation.
• Performed computer simulations for prototypical simple-liquid systems.
• Analyzed the linear scaling of s2(L) with 1/L and D*(L) with system size.

Main Results:

• Demonstrated that s2(L) scales linearly with 1/L.
• Showed that D*(L) exhibits similar linear scaling behavior.
• Found that parameters A(L) and α(L) are linearly proportional to 1/L.
• Extrapolated to the thermodynamic limit, yielding coefficients A∞ = 0.048 ± 0.001 and α∞ = 1.000 ± 0.013.

Conclusions:

• The study confirms universal values for A∞ and α∞, consistent with prior literature.
• A power law relation between scaling coefficients suggests a constant viscosity-to-entropy ratio in simple liquids.