A study of the evaporation and condensation of n-alkane clusters and nanodroplets using quantum chemical methods
A study of the evaporation and condensation of n-alkane clusters and nanodroplets using quantum chemical methods
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DOI：
10.1016/j.fluid.2014.01.010
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发表时间：
2014-03-25
影响因子：
2.6
通讯作者：
Sazhin, Sergei S.
中科院分区：
文献类型：
--
作者：
Gun'ko, Vladimir M.;Nasiri, Rasoul;Sazhin, Sergei S.
使用量子化学溶剂化模型（SMD）和动力学气体理论分析了来自分子簇和纳米液滴的C-8-C-27范围内的正烷烃分子的蒸发速率（γ），假设系统处于热力学平衡状态（蒸发和冷凝速率相等）。在300-640 K下计算液滴尺寸、液体密度、蒸发焓和蒸发的吉布斯自由能。量子化学计算（SMD/HF或SMD/B3 LYP方法，具有6- 31 G（d，p）基组）用于估计分子从液体介质（簇或纳米液滴）转移到气相期间吉布斯自由能的变化。动力学气体理论被用来估计分子/团簇/纳米液滴在气相中的碰撞速率。该速率取决于分子和簇/纳米液滴的分压、温度、尺寸和质量。从辛烷到二十七烷的蒸发烷烃的分子大小的增加导致γ值的强烈降低。蒸发/冷凝系数的初步估计，直接分析的基础上的碰撞的单个分子与分子簇，提出。皇冠版权所有（C）2014由爱思唯尔B. V.出版保留所有权利。
The evaporation rate (gamma) of n-alkane molecules in the C-8-C-27 range from molecular clusters and nanodroplets is analysed using the quantum chemical solvation model (SMD) and the kinetic gas theory, assuming that the system is in a state of thermodynamic equilibrium (evaporation and condensation rates are equal). The droplet size, liquid density, evaporation enthalpy and Gibbs free energy of evaporation are calculated at 300-640 K The quantum chemical calculations (SMD/HF or SMD/B3LYP methods with the 6-31G(d,p) basis set) are used to estimate changes in the Gibbs free energy during the transfer of a molecule from a liquid medium (clusters or nanodroplets) into the gas phase. The kinetic gas theory is used to estimate the collision rate of molecules/clusters/nanodroplets in the gas phase. This rate depends on partial pressures, temperature, sizes and masses of molecules and clusters/nanodroplets. An increase in the molecular size of evaporated alkanes from octane to heptacosane results in a strong decrease in the values of gamma. Preliminary estimates of the evaporation/condensation coefficient, based on the direct analysis of the collisions of individual molecules with molecular clusters, are presented. Crown Copyright (C) 2014 Published by Elsevier B.V. All rights reserved.