with 𝑎 𝑖 the hydration radius. This extra term accounts for volume exclusion through steric effects , the system of equations using Equation with 𝜀 = 80.23𝜀 0 the dielectric constant of water. The creation of depletion of particles due to chemical reactions is of importance here, so particle conservation is balanced with a source or sink term 𝑅 𝑖 in the continuity equation: