Prediction on dielectric strength and boiling point of gaseous molecules for replacement of SF6
Prediction on dielectric strength and boiling point of gaseous molecules for replacement of SF6
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DOI：
10.1002/jcc.24741
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发表时间：
2017-04
影响因子：
3
通讯作者：
Xiaojuan Yu;Hua Hou;Baoshan Wang
中科院分区：
文献类型：
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作者：
Xiaojuan Yu;Hua Hou;Baoshan Wang
开发环境友好的绝缘气体以替代六氟化硫（SF6）引起了大量的实验和理论关注，但尚未成功。本文提出了一种计算任意气体分子的介电强度和沸点的方法，用于分子设计和筛选。新的构效关系（SAR）模型是通过将静电势表面的密度依赖性（包括表面积和表面电位的统计方差）与分子性质（包括极化率、电负性和硬度）相结合而建立的。SAR模型中的所有描述子都是用密度泛函理论计算的。系统地研究了不同官能团对SF6的取代效应。结果表明，CF3是提高介电强度最有效的官能团，因为它具有大的比表面积和极化率。然而，所有的替代品都表现出比SF6更高的沸点，因为分子硬度降低。Er和Tb之间的平衡可以通过最小化分子的局部极性来实现。SF_5CN和SF_5CFO具有较高的介电强度和较低的沸点，是替代SF_6的理想材料。© 2017 Wiley Periodicals，Inc.
Developing the environment‐friendly insulation gases to replace sulfur hexafluoride (SF6) has attracted considerable experimental and theoretical attentions but without success. A computational methodology was presented herein for prediction on dielectric strength and boiling point of arbitrary gaseous molecules in the purpose of molecular design and screening. New structure–activity relationship (SAR) models have been established by combining the density‐dependent properties of the electrostatic potential surface, including surface area and the statistical variance of the surface potentials, with the molecular properties including polarizability, electronegativity, and hardness. All the descriptors in the SAR models were calculated using density functional theory. The substitution effect of SF6 by various functional groups was studied systematically. It was found that CF3 is the most effective functional group to improve the dielectric strength due to the large surface area and polarizability. However, all the substitutes exhibit higher boiling points than SF6 because the molecular hardness decreases. The balance between Er and Tb could be achieved by minimizing the local polarity of the molecules. SF5CN and SF5CFO were found to be the potent candidates to replace SF6 in view of their large dielectric strengths and low boiling points. © 2017 Wiley Periodicals, Inc.