The classical Kelvin formula for the equilibrium vapor pressure over a droplet of radius R$R$ is extended to small radii and vapor non-ideality, from where the limiting supersaturation condition is obtained by relating the point R=0$R=0$ to the value of limiting (spinodal) supersaturation of vapor. The analysis of different dependences of the Tolman length on radius, δ(R)$\delta (R)$, obeying this condition suggests that (i) the value of δ(0)$\delta (0)$ is positive and the function δ(R)$\delta (R)$ decreases with increasing radius; (ii) the curvature effect (the dependence of surface tension on radius) in the nucleation region is determined by the value of δ(0)$\delta (0)$. At the same time, this effect is weakly sensitive to the form of the function δ(R)$\delta (R)$ and insensitive to its asymptotic value δ_∞${\delta }_{\infty }$ .

半径为R的液滴上的平衡蒸气压的经典开尔文公式$\mathrm{[R}$扩展到小半径和蒸汽非理想状态，从中通过将点R = 0关联起来获得极限过饱和条件$\mathrm{[R}=0$达到蒸汽的极限（尖峰）过饱和度的值。托尔曼长度对半径δ（R）的不同依赖性的分析$\delta （\mathrm{[R}）$，服从该条件表明（i）δ（0）的值$\delta （0）$为正且函数δ（R）$\delta （\mathrm{[R}）$随着半径的增加而减小；（ii）成核区域的曲率效应（表面张力对半径的依赖性）由δ（0）的值确定$\delta （0）$。同时，此效应对函数δ（R）的形式微弱敏感$\delta （\mathrm{[R}）$并且不受其渐近值δ _∞${\delta }_{\infty }$ 。