Radial distribution function

In statistical mechanics, the radial distribution function, (or pair correlation function) g ( r ) {\displaystyle g(r)} in a system of particles (atoms, molecules, colloids, etc.), describes how density varies as a function of distance from a reference particle. If a given particle is taken to be at the origin O, and if ρ = N / V {\displaystyle \rho =N/V} is the average number density of particles, then the local time-averaged density at a distance r {\displaystyle r} from O is ρ g ( r ) {\displaystyle \rho g(r)} .

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