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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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本文对正戊烷(n-pentane)分子构象进行了理论研究,给出了不同构象分子价轨道的能级分布和电子动量分布,进而分析引入电子动量谱学(EMS)作为一种新的实验探测手段,把电子动量谱学推向有机分子构象研究领域。 相似文献
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利用第三代电子动量谱仪首次获得了四氢呋喃和二恶烷HOMO轨道的电子动量分布,并将实验结果与不同构象的理论计算进行了比较,四氢呋喃的C1,Cs构象和二恶烷C2h构象的理论曲线分别与各自实验结果符合较好. 相似文献
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从第一性原理出发,采用杂化的密度泛函理论和弹性散射格林函数法,计算有机分子4,4'-二巯基二苯醚分子的电子结构并研究其电子输运性质.计算结果表明,电场对分子系统电子结构有明显的影响,电流、电导表现为非线性变化,与不考虑电场作用时相比,更为接近实验结果. 相似文献
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对一类以双酚A为连接链,9,10-二甲氧基蒽为电子给体,带不同取代基的苯为电子受体的给体-受体体系的光致电子转移反应的重组能进行了理论计算研究,获得与实验值接近的结果,说明所用的理论计算方法具有可行性。 相似文献
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本文对正戊烷(n-pentane)分子构象进行了理论研究,给出了不同构象分子价轨道的能级分布和电子动量分布,进而分析引入电子动量谱学(EMS)作为一种新的实验探测手段,把电子动量谱学推向有机分子构象研究领域. 相似文献
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β胡萝卜素是典型的线性多稀分子,重要的光电材料,在医学上也有重要的作用,研究它在外场作用下分子结构和性能的变化及机理有很重要的理论和应用价值。分别测量了β胡萝卜素在二甲基亚砜中温度为81~25 ℃范围和β胡萝卜素在二硫化碳中压力为0.04~0.60 GPa范围的紫外-可见吸收和共振拉曼光谱。发现了两种不同的的光谱现象,随温度降低,二甲基亚砜中的β胡萝卜素分子的紫外-可见吸收、拉曼光谱都红移,拉曼散射截面增大;而随压强增加二硫化碳中β胡萝卜素分子的紫外-可见吸收峰也红移,但拉曼散射峰却蓝移,拉曼散射截面减小。两种实验现象不能同时用线性多烯分子的“有效共轭长度”“弱阻尼相干振动”等理论模型给予明了解释。电子—声子耦合常数,可以表征分子中的原子和电子在外界环境作用下的相互振动耦合程度的强弱。该研究依据电子—振动相互作用规律,通过分析和计算得出结论:二种实验现象都是π电子与碳碳键振动相互作用产生的,即由于温度、压力作用对β胡萝卜素分子结构及电子—振动耦合影响不同, 引起电子-声子耦合常数不同,是电子能隙对碳碳振动的调制作用而产生的两种实验结果。 相似文献
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在600 eV,1200 eV,2400 eV三个入射能下首次实验测量了环己二烯的价壳层电离能谱和内价分子轨道4a的电子动量谱,并将实验结果与密度泛函理论和Hatree-Fock在不同基组下的计算作了比较. 相似文献
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We present what is to our knowledge the first experimental implementation of a ghost imaging protocol based on an intense
multimode spontaneous parametric down-conversion process, that is a PDC starting from vacuum. Temporal and spatial properties
of the quantum field used in the protocol are also discussed. 相似文献
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DNA replication is an essential process in biology and its timing must be robust so that cells can divide properly. Random fluctuations in the formation of replication starting points, called origins, and the subsequent activation of proteins lead to variations in the replication time. We analyze these stochastic properties of DNA and derive the positions of origins corresponding to the minimum replication time. We show that under some conditions the minimization of replication time leads to the grouping of origins, and relate this to experimental data in a number of species showing origin grouping. 相似文献
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The calculation of the response of CR-39 detectors exposed to neutrons is of high importance for their dosimetric application. A computer code system has been developed for this purpose. Whereas the generation of secondary charged particles is carried out using non-analogue Monte-Carlo techniques with variance reduction the simulation of the track formation process is treated without any free parameter starting from the etch rate ratio V(REL) only. Results are given for the contribution of recoil protons to the response as a function of the neutron energy and angle of incidence. Furthermore, the influence of an external radiator has been studied. The comparison of the calculated values with experimental data confirm the reliability of the track etch model applied. 相似文献
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H. Walliser K. Wildermuth F. Gönnenwein 《Zeitschrift für Physik A Hadrons and Nuclei》1988,329(2):209-215
Internal excitations of the fissioning nucleus are usually described phenomenologically by friction terms. In the present paper an approach is discussed which is in principle based on a correct quantum mechanical treatment taking the projection form of the Schrödinger equation as a starting point. Considering nuclear fission as an almost adiabatic process an estimate for the friction energy is made. In this very crude estimate only 10–15% of the collective energy gain in going from the saddle to the scission point is transformed into internal excitation energy. This is in agreement with experimental data showing pronounced substructure effects which would be destroyed in the presence of a larger friction. As compared to other microscopic calculations, in the present work the total Hamiltonian is split in such a way that the only perturbation term being responsible for the deformation is essentially the Coulomb energy. By this assumption the calculation of transition probabilities to intrinsically excited states becomes rather insensitive to the exact excitation energy spectrum of the compound nucleus. 相似文献
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Modeling the effects of cohesive energy for single particle on the material removal in chemical mechanical polishing at atomic scale 总被引:1,自引:0,他引:1
This paper proposes a novel mathematical model for chemical mechanical polishing (CMP) based on interface solid physical and chemical theory in addition to energy equilibrium knowledge. And the effects of oxidation concentration and particle size on the material removal in CMP are investigated. It is shown that the mechanical energy and removal cohesive energy couple with the particle size, and being a cause of the non-linear size-removal rate relation. Furthermore, it also shows a nonlinear dependence of removal rate on removal cohesive energy. The model predictions are in good qualitative agreement with the published experimental data. The current study provides an important starting point for delineating the micro-removal mechanism in the CMP process at atomic scale. 相似文献
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A novel concept is presented for the pulse generation in the linear regime of an actively loss modulated laser. Introducing collective laser modes, the frequency detuning of the modulator and the statistical initial situation of the laser starting from spontaneous emission become tractable. Formation of a mode-locked pulse is described by the selection of collective modes. Perfect mode locking corresponds to the survival of a single mode in the build-up process. A variety of laser properties is derived from the solution and compared with experiment. The model predicts imperfect mode locking (with a finite number of collective modes) in the transient case in agreement with experimental findings. 相似文献
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In order to quantify the surface charging of a plasma actuator using surface Dielectric Barrier Discharge, we propose a new equivalent circuit for this surface DBD and a new simple method allowing the measurement of the surface charging during the first half cycle and the discharging during the other half cycle. Using this method, we observed the temporal evolution of the total charge on the dielectric surface during an operation of a SDBD starting with positive cycle. We also observed the same phenomenon during an operation starting with a negative cycle. The comparison between these two observations suggests that the high electro-negativity of oxygen plays an important role in these discharges. Finally, we compare the total amount of charge transferred over a cycle under different experimental conditions and we find that the transfer is the lowest in oxygen and the highest in nitrogen. 相似文献