共查询到20条相似文献,搜索用时 31 毫秒
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报道了环戊烯(C5H8)分子1a′轨道的电子动量谱,并且给出了价 轨道的电离能谱信息 .实验在非共面对称几何条件下用能量多道型电子动量谱仪完成,入射电子的能量为1200 eV 加结合能.通过Hartree-Fock 和密度泛函方法计算得到了C5H8分子 1a′轨道的动量谱. 对1a′轨道的电子动量谱的实验值和理论计算进行了比较,得到了该轨道的极强度(pole s trength)的信息. 相似文献
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利用第三代高效率电子动量谱仪,分别在600和1500 eV两种不同入射电子能量下获得了二茂铁(ferrocene)分子外价轨道的电离能谱和电子动量谱的相关实验结果.并利用非相对论与标量相对论密度泛函方法计算出了二茂铁的重叠型和交错型两种不同构象的理论动量谱.两种构象的外价轨道一一对应,理论电子动量谱基本一样.对二茂铁的外价轨道,在低动量区观测到了强烈的扭曲波效应,这与这些轨道主要由铁原子的3d轨道构成有关.通过相对论和非相对论计算结果的比较,表明相对论效应对于二茂铁的外轨道动量分布几乎没有影响.
关键词:
二茂铁分子
电子动量谱
相对论效应
扭曲波效应 相似文献
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由于工业的迅速发展 ,使得空气质量急剧下降 ,因此对影响大气的分子进行深入研究变得非常必要 .本实验室已经对影响环境的甲烷[1] 、丙烷[2 ] 、CO2 [3] 等分子进行了电子动量谱研究 ,为环保提供了有用的数据 .CFCl3作为工业广泛应用的气雾剂和制冷剂原料 ,它的大量使用导致了大气中臭氧的减少[4 ] .前人已用光电子谱学的方法[5- 8] 研究了CFCl3,我们又用电子动量谱的手段对CFCl3分子进行了进一步的研究 ,即从波函数的层次上详细了解CFCl3的电子结构 .(e ,2e)电子动量谱学在研究分子的电子结构方面有非常独特的优越性[9- 12 ] ,它可以… 相似文献
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Kedong Wang Liqing Chen Xu Shan Xingju Wu Kezun Xu Xiangjun Chen 《Journal of Electron Spectroscopy and Related Phenomena》2009,173(2-3):96-102
The binding energy spectra and electron momentum density distributions for the valence orbitals of CF2Br2 have been obtained by using electron momentum spectroscopy (EMS) at an impact energy of 1200 eV plus binding energy. The measured electron momentum profiles are compared with Hartree–Fock (HF) and density functional theory (DFT) calculations with different-sized basis sets. In general, the DFT-B3LYP calculation using the large basis sets of 6-311++G** and aug-cc-pVTZ fairly describe the experimental results. Moreover, the controversial orderings of the outer valence orbitals have been reassigned. The pole strength of the main ionization transition from the inner valence orbital of 1b2 is determined. 相似文献
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在高分辨率(ΔE=08?eV,Δp≈01a.u.)高效率的第三代电子动量谱仪上获得了N2价轨道的电离能谱和动量谱.通过对伴线结构的电子动量谱学(EMS)研究,得到了不同伴线结构的电子动量谱,另一方面也得到了伴线结构的强度.由伴线的电子动量分布形状判断出其跃迁的主要来源,并由实验测量的伴线结构强度确定了谱因子(极强度)的大小,通过对谱因子实验值与理论计算结果的比较检验了各种理论模型的精确度.
关键词:
氮分子
价轨道
电子动量谱
电子关联效应 相似文献
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本文主要讨论了脯氨酸分子最稳定的四种构象的束缚能谱和轨道电子动量分布。计算出的几何构型和偶极矩等分子特征与以前的实验和理论计算结果均很好的符合。双空间分析就是用基于B3LYP/TZVP密度泛函计算出的位置空间来研究其束缚能谱,用基于平面波近似下的动量空间来研究其价壳层轨道电子动量分布,并从构象之间的转换来解释不同构象轨道(HOMO:31a,NHOMO-1:30a和HOMO-2:29a)波函数差异。 相似文献
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Yang Xue-feng Wu Fang Shan Xu Yan Mi Wang Ke-dong Xue Xin-xia Chen Xiang-jun Xu Ke-zun 《Frontiers of Physics in China》2006,1(4):424-427
The first measurement of the complete valence shell binding energy spectra of chlorobromomethane (CH2 BrCl) is reported by (e, 2e) electron momentum spectrometer using symmetric non-coplanar geometry at an impact energy of
1200 eV plus binding energy. The experimental electron momentum profiles of the highest occupied molecular orbitals (HOMOs)
are extracted and compared with Hartree-Fock (HF) and density functional theory (DFT) calculations. DFT calculation employing
B3LYP hybrid functional and the large-sized basis sets provides the best agreement with the experiment. 相似文献
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利用第三代电子动量谱仪研究了苯甲醇(C_6H_5CH_2OH)分子的最高占据轨道(HOMO)和次最高占据轨道(N-HOMO)电子动量谱,给出了外价轨道的电离能谱信息.实验在非共面对称几何条件下完成,入射电子的能量为2400 eV加结合能.通过密度泛函方法计算得到了苯甲醇分子最高和次最高占据轨道的动量谱,理论与实验结果符合较好. 相似文献
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利用不对称不共面电子动量谱仪,在2.5 keV碰撞能量下,采用高精度的SAC-CI方法计算了1-碘丙烷分子束缚能谱,同时采用Hartree-Fock、B3LYP/aug-cc-pVTZ(C,H)6-311G**(I)方法计算其电子动量分布. 并对电离能峰进行了标示. 结合非相对论与相对论计算方法以及自然键轨道分析,对最外层两个轨道(碘的5p孤对)的自旋-轨道耦合效应与分子内轨道相互作用进行了比较. 两种相互作用对电子动量分布的不同影响是可观的. 实验结果与相对论计算的结果一致,表明1-碘丙烷分子内自旋-轨道耦合效应占主导. 相似文献
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Investigation of outer valence orbital of CF2Cl2 by a new type of electron momentum spectrometer 下载免费PDF全文
Electronic states of CF2Cl2 (dichlorodifluoromethane, Freon 12) have been studied using a new type of electron momentum spectrometer with a very high efficiency at an impact energy of 1200 eV plus binding energy. The experimental electron momentum profiles are compared with the density functional theory (DFT) and Hartree-Fock (HF) calculations. The relationship between orbital assignments in different coordinate systems is discussed. A new method of difference analysis based on the new type of electron momentum spectrometer is used to clarify the ambiguities regarding the orbital ordering. 相似文献
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S. Dey A.J. Dixon I.E. McCarthy E. Weigold 《Journal of Electron Spectroscopy and Related Phenomena》1976,9(4):397-412
The 400-eV and 1200-eV non-coplanar symmetric (e, 2e) reaction has been used to measure the momentum distributions of electrons in the individual valence orbitals of ethane as well as to measure the complete separation energy spectra in the valence region. The shapes and relative magnitudes of the momentum distributions agree well with those calculated using the plane wave off-shell impulse approximation and double zeta basis molecular orbital wave functions. The ground state of C2H6+ is shown to be 1eg?1, with the vertical ionization potential being 12.25 ± 0.1 eV. Considerable structure due to configuration interaction is observed in the separation energy region 29–55 eV. Much of this structure can be assigned to the 2a1g orbital. 相似文献
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I. H. Suzuki E. Weigold C. E. Brion 《Journal of Electron Spectroscopy and Related Phenomena》1980,20(3):289-303
The binding energy spectra and momentum distributions for the valence orbital transitions of molecular oxygen have been obtained using the (e,2e) reaction at total electron energies of 400 and 1200 eV. The outer πg orbital is found to have a wave-function which is significantly more extended in momentum space than that of the more-tightly bound πu orbitals. This is interpreted as a consequence of the single occupancy of the anti-bonding πg orbitals. Peaks at 39 and 47 eV are assigned to 4,2Σg− ion states on the basis of the observed momentum distributions. The momentum distribution and observed intensity for the 32.5 eV transition supports the assignment of 2 Πu for this ion state. The measured relative strengths for the various Πu and Σu transitions are in qualitative agreement with CI and Green's function calculations. 相似文献
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C.E. Brion I.E. McCarthy I.H. Suzuki E. Weigold G.R.J. Williams K.L. Bedford A.B. Kunz R. Weidman 《Journal of Electron Spectroscopy and Related Phenomena》1982,27(2):83-107
Electron binding energy spectra and momentum distributions have been obtained for the valence orbitals of HBr and HI using noncoplanar symmetric electron coincidence spectroscopy at 1200 eV. The weakly bonding inner valence ns orbitals, which have not been observed previously, have their spectroscopic (pole) strength severely split among a number of ion states. For HBr the strength of the “main” inner valence (ns) transition is 0.42±0.03 whereas for HI it is 0.37±0.04, in close agreement with the value observed for the valence s orbitals of the corresponding isoelectronic inert-gas atoms. The spectroscopic strength for the two outermost orbitals is found to be close to unity, in agreement with many-body Green's function calculations. The measured momentum distributions are compared with several spherically averaged MO momentum distributions, as well as (for HBr) with a Green's function calculation of the generalized overlap amplitude (GOA). The GOA momentum distributions are in excellent agreement with the HBr data, both in shape and relative magnitude. Not all of the MO momentum distributions are in reasonable agreement with the data. Comparison is also made with the calculated momentum distributions for Kr, Br, Xe and I. 相似文献
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J.P.D. Cook M.G. White C.E. Brion W. Domcke J. Schirmer L.S. Cederbaum W. von Niessen 《Journal of Electron Spectroscopy and Related Phenomena》1981,22(3):261-270
The valence shell binding energy spectrum of carbonyl sulphide (10–45 eV) has been measured using both binary (e,2e) and dipole (e,2e) electron impact spectroscopy and calculated by the 2ph-TDA many body Green's function technique. The spectrum shows extensive structure above 20 eV, indicating a major breakdown of the quasi-particle picture for ionization of COS. The calculation is in good agreement with the present experimental and literature ESCA binding energy spectra. Binary (e,2e) spectra at two azimuthal angles support the theoretical prediction that this extensive final ion state structure arises primarily from ionization of the COS 6σ and 7σ inner valence electrons. 相似文献