The homogeneous nucleation rate of the liquid phase from a supersaturated propylene glycol vapor is a key factor in aerosol formation from condensation aerosol generators. The droplet nucleation rate is difficult to measure experimentally at high supersaturations. This paper demonstrates the feasibility of using classical Molecular Dynamics (MD) simulations to describe the nucleation of propylene glycol from the vapor phase in air at 320 and 343 K. After an initial induction period, nucleation was observed in many of the scenarios studied here. The classical nucleation theory underestimates the nucleation rate compared to the MD simulation results at high supersaturations. However, a kinetic model that assumed no free energy barrier to nucleation had better agreement with the MD predictions at extremely high supersaturations. For systems where a quasi-steady state was reached during the simulation, it is possible to determine the nucleation free energy as a function of cluster size. From this analysis it is found that the MD simulations predict over a factor of two larger critical clusters and about 50% higher free energy barriers than the classical nucleation theory.

来自过饱和丙二醇蒸气的液相的均匀成核速率是由冷凝气溶胶发生器形成气溶胶的关键因素。液滴成核速率很难在高过饱和度下通过实验测量。本文证明了使用经典分子动力学（MD）模拟来描述丙二醇在320和343 K下从空气中的气相成核的可行性。在初始诱导期之后，在本文研究的许多场景中都观察到了成核。与高过饱和度的MD模拟结果相比，经典成核理论低估了成核速率。但是，在极高的过饱和度下，假定没有自由能成核障碍的动力学模型与MD预测具有更好的一致性。对于在仿真过程中达到准稳态的系统，可以确定成核自由能随簇大小的变化。从该分析中发现，与经典成核理论相比，MD模拟预测的因素是两个更大的临界簇和大约高出50％的自由能垒。