共查询到18条相似文献,搜索用时 140 毫秒
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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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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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利用新一代高性能(e,2e)电子动量谱仪,在400-2400 eV的大范围入射电子能量条件下,测量了乙烯分子电子密度的动量分布.实验测量的乙烯1b3g轨道电子动量分布与平面波冲量近似的理论计算结果相比,在低动量区和高动量区出现明显的上翘(turn up)效应,并且此上翘效应随着入射电子能量的增加而逐渐减小.进一步的分析证实由于分子的扭曲波效应引起1b3g轨道动量分布在低动量区和高动量区的上翘.实验测量结果将对分子扭曲波理论计算的建立提供实验依据. 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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We study the spin edge states, induced by the combined effect of Bychkov-Rashba spinorbit and Zeeman interactions or of Dresselhaus
spin-orbit and Zeeman interactions in a twodimensional electron system, exposed to a perpendicular quantizing magnetic field
and restricted by a hard-wall confining potential. We derive an exact analytical formula for the dispersion relations of spin
edge states and analyze their energy spectrum versus the momentum and the magnetic field. We calculate the average spin components
and the average transverse position of electron. It is shown that by removing the spin degeneracy, spin-orbit interaction
splits the spin edge states not only in the energy but also induces their spatial separation. Depending on the type of spin-orbit
coupling and the principal quantum number, the Zeeman term in the combination with spin-orbit interaction increases or decreases
essentially the splitting of bulk Landau levels while it has a weak influence on the spin edge states. 相似文献
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用非相对论、标量相对论和二分量相对论三种不同的密度泛函方法对UF_6分子的电子结构进行了量子化学计算,并利用编写的程序计算出了三种方法下各个价轨道的电子动量谱,比较了三种方法计算的价轨道能级及动量分布的差异.结果表明,相对论效应不仅使UF_6的能级劈裂和移动,而且对部分价轨道电子动量分布有显著的影响. 相似文献
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Experimental and calculated momentum densities for the complete valence orbitals of the antimicrobial agent diacetyl 下载免费PDF全文
The first electronic structural study of the complete valence shell binding energy spectra of the antimicrobial agent diacetyl, encompassing both the outer and inner valence regions, is reported. The binding energy spectra as well as the individual orbital momentum profiles have been measured by using a high resolution (e, 2e) electron momentum spectrometer (EMS) at an impact energy of 1200eV plus the binding energy, and using symmetric noncoplanar kinematics. The experimental orbital electron momentum profiles are compared with self-consistent field (SCF) theoretical profiles calculated using the Hartree-Fock approximation and Density Functional theory predictions in the target Kohn-Sham approximation which includes some treatment of correlation via the exchange and correlation potentials with a range of basis sets. The pole strengths of the main ionization peaks from the inner valence orbitals are estimated. 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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《中国物理快报》2021,(5)
We study the multiphoton ionization of potassium atoms in 800 nm and 400 nm femtosecond laser fields.In the 800 nm laser field,the potassium atom absorbs three photons and emits one electron via one photon resonance with the 4p intermediate state with the help of the ac-Stark shift.The resonance feature is clearly shown as an Autler-Townes(AT) splitting and is mapped out in the electron kinetic energy spectrum.In a 400 nm laser field,although one photon resonance is possible with the 5p state,no splitting is observed.The different transition amplitudes between 4s-4p and 4s-5p explain the observed results.Due to the AT effect,an unexpected peak in the photoelectron energy spectrum that violates the dipole transition rule is observed.A preliminary explanation involving the spin-orbit interaction in the p state is given to account for this component.The observed ATsplitting in the electron kinetic energy distribution can be used as an effective method to calibrate the intensity of a laser field. 相似文献
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Wavelength modulated absorption spectra of the free excitons in 6H, 15R and 3C SiC have been measured. The spin-orbit splitting of the valence bands of the uniaxial and cubic polytypes are found to be 7 and 10 meV respectively. Using a new value for the exciton binding energy of 27 meV, an improved value of the fundamental gap of cubic SiC, Eg = 2.417 eV, is derived. Due to the small spin-orbit splitting, the valence bands are highly non-parabolic at low energies. 相似文献