Infrared absorption spectra, radiative efficiencies, and global warming potentials of perfluorocarbons: Comparison between experiment and theory
Infrared absorption spectra, radiative efficiencies, and global warming potentials of perfluorocarbons: Comparison between experiment and theory
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DOI：
10.1029/2010jd014771
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发表时间：
2010-12-31
影响因子：
4.4
通讯作者：
Wallington, Timothy J.
中科院分区：
文献类型：
--
作者：
Bravo, Ivan;Aranda, Alfonso;Wallington, Timothy J.
实验和理论确定了一系列直链全氟碳化合物的红外光谱：C2F6， C3F8, C4F10, C5F12， C6F14和C8F18。理论谱用密度泛函（DFT）和从头算方法确定。使用Pinnock等人（1995）的方法确定辐射效率，并结合文献中的大气寿命来确定全球变暖潜值。理论测定的吸收截面在实验测定值的10%以内。尽管计算成本要低得多，但DFT计算通常比从头算方法表现得更好。在基本C-F振动区域，辐射强迫具有很强的波数依赖性，并且理论和实验确定的波段位置之间波长的微小差异对re有显著影响。我们对理论光谱进行了经验校正，然后在一些支链和环全氟烷烃上测试了这种校正。然后，我们计算了另一组全氟烯烃的吸收截面、REs和gwp。
Experimentally and theoretically determined infrared spectra are reported for a series of straight-chain perfluorocarbons: C2F6, C3F8, C4F10, C5F12, C6F14, and C8F18. Theoretical spectra were determined using both density functional (DFT) and ab initio methods. Radiative efficiencies (REs) were determined using the method of Pinnock et al. (1995) and combined with atmospheric lifetimes from the literature to determine global warming potentials (GWPs). Theoretically determined absorption cross sections were within 10% of experimentally determined values. Despite being much less computationally expensive, DFT calculations were generally found to perform better than ab initio methods. There is a strong wavenumber dependence of radiative forcing in the region of the fundamental C-F vibration, and small differences in wavelength between band positions determined by theory and experiment have a significant impact on the REs. We apply an empirical correction to the theoretical spectra and then test this correction on a number of branched chain and cyclic perfluoroalkanes. We then compute absorption cross sections, REs, and GWPs for an additional set of perfluoroalkenes.