【摘要】 本文利用尺寸选择的光电子能谱和密度泛函理论计算,研究了Co_nC₃^-/0和Co_nC₄^-/0（n=1～4）团簇的结构演化和电子特性.通过测量它们的光电子能谱获得了它们的绝热脱附能和垂直脱附能.通过比较理论计算结果和实验数据,确定了最稳定结构.研究结果表明随着Co原子的增加Co_nC₃^-/0和Co_nC₄^-/0团簇中的C原子被逐渐分离开,但在n=4时仍然含有一个C₂单元.有趣的是,结果表明负离子团簇Co₂C₃^-和Co₂C₄^-是平面结构,而对应的中性团簇都是Co原子位于碳链末端的线性结构.负离子Co₃C₃^-是一个平面结构,其中四元环Co₂C₂和四元环Co₃C共用一个Co-Co键,而中性的Co₃C₃是一个三维结构,其中一个C₂单元和一个C原子连接在三角形Co₃的两个面.更多还原

【Abstract】 We investigated the structural evolution and electronic properties of Co_nC₃^-/0 and Co_nC₄^-/0（n=1-4） clusters by using mass-selected photoelectron spectroscopy and density functional theory calculations. The adiabatic and vertical detachment energies of Co_1-4C₃^-and Co_1-4C₄^-were obtained from their photoelectron spectra. By comparing the theoretical results with the experimental data, the global minimum structures were determined. The results indicate that the carbon atoms of Co_nC₃^-/0 and Co_nC₄^-/0（n= 1-4） are separated from each other gradually with increasing number of cobalt atoms but a C2 unit still remains at n=4. It is interesting that the Co₂ C₃^-and Co₂ C₄^-anions have planar structures whereas the neutral Co₂ C₃ and Co₂ C₄ have linear structures with the Co atoms at two ends.The Co₃ C₃^-anion has a planar structure with a Co₂ C₂ four-membered ring and a Co₃ C four-membered ring sharing a Co-Co bond, while the neutral Co₃ C₃ is a three-dimensional structure with a C2 unit and a C atom connecting to two faces of the Co₃ triangle.更多还原