Erbahar Dogan, Susi Toma, Rocquefelte Xavier, Bittencourt Carla, Scardamaglia Mattia, Blaha Peter, Guttmann Peter, Rotas Georgios, Tagmatarchis Nikos, Zhu Xiaohui, Hitchcock Adam P, Ewels Chris P
Institut des Matériaux Jean Rouxel, Université de Nantes, CNRS, Nantes, France.
Physics Department, Gebze Technical University, Gebze, Turkey.
Sci Rep. 2016 Oct 17;6:35605. doi: 10.1038/srep35605.
C fullerene crystals may serve as important catalysts for interstellar organic chemistry. To explore this possibility, the electronic structures of free-standing powders of C and (CN) azafullerenes are characterized using X-ray microscopy with near-edge X-ray adsorption fine structure (NEXAFS) spectroscopy, closely coupled with density functional theory (DFT) calculations. This is supported with X-ray photoelectron spectroscopy (XPS) measurements and associated core-level shift DFT calculations. We compare the oxygen 1s spectra from oxygen impurities in C and CN, and calculate a range of possible oxidized and hydroxylated structures and associated formation barriers. These results allow us to propose a model for the oxygen present in these samples, notably the importance of water surface adsorption and possible ice formation. Water adsorption on C crystal surfaces may prove important for astrobiological studies of interstellar amino acid formation.
C富勒烯晶体可能是星际有机化学的重要催化剂。为探究这种可能性，利用具有近边X射线吸收精细结构（NEXAFS）光谱的X射线显微镜对独立的C和（CN）氮杂富勒烯粉末的电子结构进行了表征，并与密度泛函理论（DFT）计算紧密结合。X射线光电子能谱（XPS）测量及相关的芯能级位移DFT计算为此提供了支持。我们比较了C和CN中氧杂质的氧1s光谱，并计算了一系列可能的氧化和羟基化结构以及相关的形成势垒。这些结果使我们能够提出一个关于这些样品中存在的氧的模型，特别是水表面吸附和可能的冰形成的重要性。C晶体表面的水吸附可能对星际氨基酸形成的天体生物学研究具有重要意义。
