Interpolating the radial distribution function in a two-dimensional fluid across a wide temperature range

Calculations of pair correlations in fluids usually require resource-intensive simulations or integral equations, while existing simple approximations lack accuracy. Here, we show that the pair correlation function for monolayer fluid-like systems can be decomposed into correlation peaks defined using Voronoi cells. Being properly normalized, these peaks exhibit a universal form, weak temperature dependence, and resemble those of an ideal gas, except for the first peak. As a result, we propose a simple and accurate approach to interpolate the pair correlation functions, suitable for molecular, colloids, and cellular fluids.