Orbital responses to methyl sites in C_nH_(2n+2) (n=1-6)
Orbital responses to methyl sites in C_nH_(2n+2) (n=1-6)作者机构:School of ScienceZhejiang University of TechnologyHangzhou 310023China Institute of Atomic and Molecular PhysicsSichuan UniversityChengdu 610065China
出 版 物:《Chinese Physics B》 (中国物理B(英文版))
年 卷 期:2012年第21卷第2期
页 面:16-22页
核心收录:
学科分类:081704[工学-应用化学] 07[理学] 08[工学] 0817[工学-化学工程与技术] 070303[理学-有机化学] 0703[理学-化学]
基 金:supported by the National Natural Science Foundation of China (Grant Nos.10974139 11104247 and 11176020)
主 题:electron momentum spectroscopy valence ionization energy charge density distribution
摘 要:Orbital responses to methyl sites in CnH2n+2 (n = 1-6) are studied by B3LYP/TZVP based on the most stable geometries using the B3LYP/aug-cc-pVTZ method. Vertical ionization energies are produced using the SAOP/et-pVQZ model for the complete valence space. The highest occupied molecular orbital (HOMO) investigations indicate the p- electron profiles in methane, ethane, propane, and n-butane. By increasing the number of carbon-carbon bonds in lower momentum regions, the s, p-hybridized orbitals are built and display strong exchange and correlation interactions in lower momentum space (P 〈 0.50 a.u.). Meanwhile, the relative intensities of the isomers in lower momentum space show the strong bonding number dependence of the carbon-carbon bonds, meaning that more electrons have contributed to orbital construction. The study of representative valence orbital momentum distribution further confirms that the structural changes lead to evident electronic rearrangement over the whole valence space. An analysis based on the isomers reveals that the valence orbitals are isomer-dependent and the valence ionization energy experiences an apparent shift in the inner valence space. However, such shifts are greatly reduced in the outer valence space. Meanwhile, the opposite energy shift trend is found in the intermediate valence space.