Co_nC_m~-团簇的光电子能谱和理论研究
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- 英文论文题名：Photoelectron spectroscopy and theoretical study of Co_nC_m~- clusters
- 论文作者：徐西玲 ; 袁金云 ; 许洪光 ; 郑卫军
- 英文论文作者：Xiling Xu ; Jinyun Yuan ; Hongguang Xu ; Weijun Zheng ; Institute of Chemistry ; Chinese Academy of Sciences ; Department of Chemical Physics ; University of Science and Technology of China
- 年：2016
- 作者机构：中国科学院化学研究所分子反应动力学国家重点实验室;中国科技大学化学物理系;
- 论文关键词：过渡金属碳化物 ; 光电子能谱
- 会议召开时间：2016-07-01
- 会议录名称：中国化学会第30届学术年会摘要集-第四十四分会：化学动力学
- 语种：中文
- 分类号：O641
- 学会代码：ZGHY
- 会议名称：中国化学会第30届学术年会-第四十四分会 ; 化学动力学
- 会议地点：中国辽宁大连
- 主办单位：中国化学会
- 学会名称：中国化学会
- 页数：1
- 文件大小：241k
- 原文格式：D
- 会议级别：全国
摘要
自1992年,Castlemen等人[1]发现过渡金属原子和碳原子可以形成具有极高稳定性的金属碳笼(Met-cars:M_8C_(12),并且可以作为制造纳米材料的基本单元之后,过渡金属碳化物的研究引起了人们的极大兴趣。已有的研究指出形成Met-cars的金属原子主要是过渡金属中靠前的3d原子(Ti,V,Cr);而靠后的3d金属原子(Co,Ni)是单壁碳纳米管生长过程中的催化剂。有关钴碳团簇的研究主要集中在小尺寸团簇上。为了研究钴碳团簇的结构演化和电子性质,我们测量了Co_nC_m~-(n=1-4;m=3,4)团簇的光电子能谱,并利用密度泛函计算了他们的结构。通过比较实验和理论结果,确定了他们的最稳定结构:CoC_3~-是C_(2v)对称的扇形结构,其它的Co_nC_3~-团簇中,C_3是以一个C原子和一个C_2二聚体与Co_n团簇相作用;CoC_4~-是C_(∞v)对称的线性结构,Co_2C_4~-和Co_3C_4~-团簇中,C_4以2个C_2二聚体分别与Co_n团簇相作用,而Co_4C_4~-团簇中C_4是以1个C_2二聚体和2个C原子的形式存在。Co_4C_4~-的结构和前过渡系金属钒和碳形成的立方体V_4C_4~-[2]的结构完全不同。分析和结论将在海报中给出。
The investigation of transition metal carbide has attracted an extensive interest since Castlemen et al. found M_8C_(12)(Met-Cars) has a high stability in 1992, which can be used as a building block to construct nanomaterials. The previous studies showed that the early and late 3d transition metals have different carbide-formation mechanisms. The stable Met-cars are formed by early 3d transition metal carbides. The late transition metals exist as catalyst in the growth process of single-wall carbon nanotube. Studies of cobalt carbon clusters mainly concentrated on the small size clusters. To investigate their structural evolution and electronic properties, we measured the photoelectron spectra of Co_nC_m~-( n=1-4; m=3,4) clusters and studied their structures by density functional calculations. The vertical detachment energies of Co_nC_m~-( n=1-4; m=3,4) were estimated from their photoelectron spectra. The most stable structures were identified by comparing the results of our calculations with the experimental data.
The investigation of transition metal carbide has attracted an extensive interest since Castlemen et al. found M_8C_(12)(Met-Cars) has a high stability in 1992, which can be used as a building block to construct nanomaterials. The previous studies showed that the early and late 3d transition metals have different carbide-formation mechanisms. The stable Met-cars are formed by early 3d transition metal carbides. The late transition metals exist as catalyst in the growth process of single-wall carbon nanotube. Studies of cobalt carbon clusters mainly concentrated on the small size clusters. To investigate their structural evolution and electronic properties, we measured the photoelectron spectra of Co_nC_m~-( n=1-4; m=3,4) clusters and studied their structures by density functional calculations. The vertical detachment energies of Co_nC_m~-( n=1-4; m=3,4) were estimated from their photoelectron spectra. The most stable structures were identified by comparing the results of our calculations with the experimental data.
引文
[1]Guo,B.C.;Kerns,K.P.;Castleman,A.W.Science.1992,255:1411.
[2]Yuan J.Y.;Wang,P.;Hou,G.L.;Feng,G.;Zhang,W.J.;Xu,X.L.;Xu,H.G.;Yang,J.L.;Zheng,W.J.J.Phys.Chem.A 2016,120:1520.
[2]Yuan J.Y.;Wang,P.;Hou,G.L.;Feng,G.;Zhang,W.J.;Xu,X.L.;Xu,H.G.;Yang,J.L.;Zheng,W.J.J.Phys.Chem.A 2016,120:1520.