Critical Droplet Nucleation — Classical Nucleation Theory

A metastable phase nucleates via droplet formation. The free energy barrier ΔG* = 16πσ³/(3Δg²) determines the nucleation rate J ∝ exp(−ΔG*/kT). Below the critical radius r* = 2σ/Δg, droplets dissolve.

Thermodynamics

Critical Droplet

r* = 2σ/Δg: —
ΔG* (barrier): —
Droplets: 0
Nucleation events: 0

CNT (Becker-Döring 1935): J = A·exp(−ΔG*/kT). Critical radius r* separates dissolving embryos from growing droplets.