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本文以聚丁(对甲苯硫酸)-2,4-己二炔-1,6-二醇酯[polylbis(p-toluene sulphonate) ester of 2,4-hexadiyne-1,6-diol](PDA-TS)单晶为例,分析其激光诱导光吸收机制,计算了单态和三态激子的结合能,认为PDA-TS中在1.35eV处的激光诱导光吸收峰是由于从3Ag到3Bu的跃迁所致,这与实验事实符合。 相似文献
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本文提出一个包括吡嗪环内部结构的多模模型来研究吡嗪桥接含Ru混合价二聚体(即C-T离子)。在C-T离子中,两个Ru离子的4dxz电子轨道经过吡嗪环的π*轨道相互耦台,把这些轨道重新组合成键合(B)、非键合(N)和反键合(A)三种类型;构成三个多维势表面,而把有关的光吸收归于电子在相应的势表面之间的跃迁,所得的结果更接近实验事实。
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类锂钙和钾离子X射线激光的实验研究 总被引:1,自引:0,他引:1
探索进入“水窗”波段以寻求X射线激光在近期的科学技术应用,是当前实验室X射光线激研究的一个重要目标.采用复合泵浦方案,我们曾用较低的驱动激光功率首次实现了类锂硅离子5f—3d(8.884nm),5d—3p(8.728nm)跃迁软X射线激光,并第一次发现了类锂硅离子的6f—3d(7.583nm)和6d—3p(7.464nm)新的X射线激光跃迁.最近,我们进一步完成了线聚焦激光辐照CaF_2和KCl平板靶的实验,探索了沿类锂离子等电子数序,将软X射线激光推进至更短波长的现实可能性,实现了类锂钙和类锂钾4f—3d跃迁的软X射线激光,波长分别为5.77nm和6.47nm,增益系数分别达到4.3cm~(-1)和1.6cm~(-1).同时也观察到了类氢氟Hα(8.09 nm)的增益,增益系数为1.4cm~(-1).实验结果进一步显示了复合泵浦类锂离子方案在实现更短波长X射线激光方面的潜力. 相似文献
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本文从理论上通过对钕玻璃中Nd~(3+)离子光吸收特性的分析,阐明了其光吸收对温度依从性的原因.在实验中,试制了几种不同类型的钕玻璃光纤温度传感探头.对Nd~(3+)离子光吸收的温度特性进行了验证,其结果和理论分析相一致,实验表明钕玻璃是一种性能良好的光纤温敏传感材料. 相似文献
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类Na铜离子软X射线激光初步研究 总被引:1,自引:0,他引:1
本文报道在上海光机所LF12~#激光装置上利用自制极紫外掠入射光栅摄谱仪,进行类Na铜离子复合泵浦软X射线激光研究的初步实验结果,低泵浦条件下(2.5×10~(12)W/cm~2)的光谱表明,得到自发发射放大是有希望的。文章还给出了类Na等电子数序列离子复合激光波长与原子序数的关系及推广到水窗波段的可能性。 相似文献
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采用飞行时间质谱计测量了纳秒激光诱导C60分子碎裂中轻碎片离子C n(n≤11)的初始平均动能,结果显示轻碎片离子具有相同的初始平均动能(约为0.34 eV),并且该动能在一定范围内不随激光通量的变化而明显改变.结合前人的实验结果,对纳秒激光诱导C60分子碎裂中轻碎片离子C n(n<30)的主要产生模式作了新的阐述,即C60分子级联发射15个C2分子和一个电子形成自身不稳定的C 30离子,在皮秒时间尺度内C 30离子的笼形结构塌陷,进而轻碎片离子产生. 相似文献
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卤化铅钙钛矿(LHPs)由于具有优异的光电性能和制备成本低等优点,已成为新一代光电器件的有力候选材料。然而,缺陷造成的离子迁移会导致LHPs纳米晶的晶体结构解离分解。因此,稳定性成为LHPs实际应用中亟待解决的问题。本文旨在研究镍离子替位掺杂及卤素空位填补对CsPbBr3纳米晶中的离子迁移抑制作用。通过离子迁移活化能的测定和高分辨透射电镜的原位观察,分析了前驱体掺杂剂对加强LHPs稳定性的作用原理。首先,选用乙酰丙酮镍和溴化镍作为掺杂剂,合成了掺杂LHPs纳米晶。其次,通过吸收-荧光光谱,X射线衍射,X射线光电子衍射,透射电子显微镜等测试手段对掺杂样品的光学及化学组成进行分析。最后,通过纳米晶薄膜电导率的温度依赖关系计算出其离子迁移活化能,并结合高分辨电镜原位观察纳米晶在高能电子束辐照下的形貌演变过程,揭示了不同掺杂剂对合成掺杂LHPs稳定性的影响。实验结果表明:Ni2+掺杂CsPbBr3样品的离子迁移活化能相较本征CsPbBr3样品(0.07 eV)有显著提升,其中乙酰丙酮镍掺杂样品的离子迁移活化能为0.238 eV,溴化镍掺杂样品的离子迁移活化能为0.487 eV。另外,电子束辐照测试表明溴化镍掺杂钙钛矿晶体表现出更高的结构稳定性,这主要归因于掺杂的Ni2+对卤素的强结合和卤素填补空位缺陷的协同钝化作用。Ni2+掺杂和卤素空位填充协同可以有效抑制卤化物钙钛矿纳米晶体中的离子迁移。 相似文献
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在半经典近似框架下,利用Scaling变换,讨论了静态形变及动力学形变对同位旋标量巨四极共振(GQR)及同位旋矢量巨偶极共振(GDR)的影响.静态形变导致双峰分裂,计算结果和实验事实相一致,动力学形变则解决了不同K(K为角动量投影)间的所有简并. 相似文献
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Jing-Cui PENG 《理论物理通讯》1994,21(3):263-268
Photo-induced absorption in halogen-bridgen nickel complexes is investigated by applying a simple 314 filled two-band discrete tight-binding Hubbard model, and the numerical result is obtained by making use of Green's function. The mechanism ofphoto-induced absorption in nickel complexes is discussed in detail. 相似文献
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Reversible shift of the optical absorption edge by the cycle of band-gap illumination and annealing has been observed for Ge-S films for the first time. Photo-induced ESR has been observed, and it is explained by two processes: (1)Increase in randomness of the structure by illumination, and (2)Trapping of free carriers excited by illumination by charged dangling bonds. The ESR signal caused by the former process does not disappear either by warming the film up to room temperature or by illuminating it with the mid-gap light, while that by the latter process disappears. 相似文献
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Photo-induced processes in organic materials mostly occur on molecular levels. Excited molecules may split to form radicals, starting a polymerization process with diffusing monomers. The azo-dyes perform an optically induced cis-trans isomerization. During pattern formation like a holographic grating, the local temperature increase, especially in thin films, is up to date a subject of estimation from absorption and dissipation data. However, the exact knowledge of the surface temperature would help a lot in understanding the resulting refractive index and thickness patterns during holographic exposure. In this paper, in-situ pyrometer measurements are presented. As examples, different photosensitive materials, varying from a photopolymer to polycrystalline azo dyes, are used in order to outline the magnitude of this effect and demonstrate the feasibility of this technique. 相似文献
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A. Molinari 《Physics Reports》1980,64(5):283-336
Photo-induced nuclear processes are revisited. The attention is focused on those topics where further investigations, carried out with the synchrotron radiation associated with LEP, are expected to promote an advance of our knowledge of the nuclear response function. A few of the possibilities offered by experimenting with laser photons backward scattered by the electrons of LEP are also considered. 相似文献
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《Journal of Physics and Chemistry of Solids》2004,65(8-9):1485-1489
Photo-induced phase transitions in spin-crossover complex [Fe(II)(2-pic)3]Cl2EtOH were investigated by X-ray absorption spectroscopy (XAS) technique. In situ XAS results showed that the metal-ligand (Fe–N) bond distance expands by ca. 0.20 Å upon photo-induced (S=0→S=2) spin conversion. We find that nearly octahedral (Oh) symmetry of FeN6 coordination remains in the photo-induced high spin state. The next-nearest neighbor Fe–C radial distribution shows a subtle change due to local distortions of ligand molecules. Inhomogeneous distribution of strains may disturb cooperative photo-induced phase transitions removing centers of inversion symmetry. 相似文献
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This study investigates a method of optical addressing in dye-doped cholesteric liquid crystals (DDCLCs). Photo-induced randomly adsorbed dyes can change the CLC textures from planar to focal conic. Such patterning can be adopted to develop a display that is initially invisible, but becomes visible upon heating above the clearing temperature, followed by cooling to room temperature. The display can also become visible upon the application of a suitable voltage, and its rapid release. Additionally, the display is thermally erasable, optically rewritable and electrically switchable. It can be applied for use as a smart card. 相似文献
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Photo-induced changes in the infrared spectrum of amorphous, evaporated As2S3 films are described. The results are interpreted in terms of the photopolymerization of As4S4 molecular units and sulfur chains into an As2S3 glassy network. The role of photo-induced charged states in the polymerization process is discussed. 相似文献
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Photo-induced magnetic phase transitions observed in Co—Fe Prussian blue analogues are discussed from a theoretical point of view. In this material a magnetization is induced by visible light, and the induced magnetization can be completely diminished not only by thermal annealing but also by irradiation of infra red light. After a brief survey of relevant experiments, we present an overview of our theoretical approaches to clarify the underlying mechanism of this interesting phenomenon. The ligand field at the Co site is shown to be the most relevant variable controlling spin states. The presence of Fe vacancies and the resultant ligand substitution by water molecules turns to be an essential prerequisite for the photoinduced magnetization. 相似文献
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Sheng-fa Fan 《Optik》2011,122(2):142-144
The optical anisotropic states in the azo-dye Disperse Red 13 doped poly(methyl methacrylate) polymeric film are induced by polarized light and the nonlinear refractive index in these states are studied by the Z-scan technique. It is found that the n2 of the sample can be controlled by changing both the polarization direction and the intensity of the 514 nm light. Photo-induced isomerization and reorientation of azo chromophores in polymer matrices are used to explain the results. 相似文献