[121], the seeding method is applicable when the size of the nucleus is the reaction coordinate for nucleation, and the capillary approximation can be safely applied (see section 2). Because analysis of seeded simulations is based on CNT, the approach is only applicable to systems that nucleate classically (see Figure ). The key expression in the seeding method is the CNT nucleation rate, i.e. Eq. 4. In this expression, CNT is used to obtain estimates of both the free energy barrier Δ𝐹 * appearing in the exponent and the prefactor 𝜌𝑓 + 𝑍, where 𝜌 is the density of growth units in solution, 𝑓 + is the attachment frequency, and 𝑍 the Zeldovich factor, expressed as a function of the crystallization driving force, as shown in Eq. 4 .