首页 | 本学科首页   官方微博 | 高级检索  
     检索      


A comparative study on the Ge6C14 heterofullerene nanocages: a density functional survey
Authors:M Koohi  M Shariati  S Soleimani Amiri
Institution:1. Young Researchers and Elites Club, North Tehran Branch, Islamic Azad University, Tehran, Iran;2. Department of Chemical Engineering, Tafresh University, Tafresh, Iran;3. Department of Chemistry, Karaj Branch, Islamic Azad University, Karaj, Iran
Abstract:Ten C14Ge6 heterofullerene isomers of C20 have been investigated by density functional theory (DFT) methods with Becke 3‐Parameter (Exchange), Lee, Yang and Parr (B3LYP) functional at the 6‐311 + G*, 6‐311++G** and AUG‐cc‐pVTZ levels. In contrast to identical bonds in the latter, contractions of C═C double bonds are encountered at the expense of longer C―Ge bonds in the former. Vibrational frequency analysis confirms that all of the nanocages are true minima. In contrast to the common belief, for obtaining highly silicon‐doped stable heterofullerenes, that the silicon dopants must be completely isolated from each other by means of strong C═C double bonds. Here, linking the germanium substitutions together is an applicable strategy for obtaining highly doped stable isolated heterofullerenes since it avoids weak heteroatom─heteroatom bonds. Therefore, none of the computed heterofullerenes collapses to open, to deform, or to segregate fullerenic cages. As to band gaps (ΔEHOMO‐LUMO), and nucleus‐independent chemical shifts at cage centers (NICS (0)), C14Ge6‐2 immerges with the highest value. Hence, it is predicted to be the most stable against electronic excitation. It contains 2 Ge─Ge single bonds at the cap‐equatorial positions. On the other hand, as to zero‐point vibrational energy and heat of atomization (ΔHat), C14Ge6‐8 appears with the lowest and highest value, respectively. It contains 6 alternating germanium atoms in the equatorial and cap positions. Thus, it is predicted to be the most thermodynamically stable. So, germanium substitution leads to a high charge distribution on the surfaces of all the isomers specially C14Ge6‐9 with +1.496 charged germanum atoms. C14Ge6 isomers seem to be a good candidate for the hydrogen storage material.
Keywords:DFT  heterofullerene  hydrogen storage  NICS  stability
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号