AUTHOR=Cheng Lin , Qin Zhaoyu , Zhang Chaohai , Shi Huixuan , Zhao Kun , Xie Xiaoyu , Ma Haibo TITLE=Theoretical Investigation of Mono- and Di-Chloro-Substitient Effects on the Insulation and Greenhouse Properties of Octafluorocyclobutane JOURNAL=Frontiers in Chemistry VOLUME=4 YEAR=2016 URL=https://www.frontiersin.org/journals/chemistry/articles/10.3389/fchem.2016.00047 DOI=10.3389/fchem.2016.00047 ISSN=2296-2646 ABSTRACT=

Octafluorocyclobutane, c-C₄F₈, and its derivatives are regarded as promising replacements of insulation gaseous SF₆, which are currently widely used in electric equipment but suffer greatly from its greenhouse effect. Based on the recent finding that the dielectric and thermodynamics properties of insulating gases are greatly dependent on the molecule's microscopic electronic and vibrational parameters, in this work, we use density functional theory (DFT) to study the molecular structures, electron affinities, and IR-active vibrational frequencies as well as thermodynamic properties for c-C₄F₈ and a series of mono-, di-substituted c-C₄F₈ compounds. It is shown that DFT calculation of perfluoro-compounds is sensitive to the chosen functional. Although all chloro-substituted c-C₄F₈ molecules are found to have much larger electron affinities, only part of them have less IR intensity in the atmospheric IR “window” than c-C₄F₈. Such a study provides useful guideline for the pre-screening search for new insulation gases via electronic structure calculations.