共查询到20条相似文献,搜索用时 46 毫秒
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Ni(en)3[Ni(en)2Ag2(NCS)6]·H2O晶体的吸收光谱和EPR谱的研究 总被引:1,自引:1,他引:0
采用半自洽场(semi-SCF) d轨道模型和点电荷模型,建立起了过渡金属离子晶体局域结构、吸收光谱与EPR谱之间的定量关系,应用高阶微扰的方法,引入平均共价因子N,统一的解释了ENST晶体中过渡金属Ni2+在D4h对称的伸长和压缩八面体时的吸收光谱、顺磁g因子和零场分裂D的值,其计算结果与实验发现较好的符合,同时本文还确定了实验中测得的零场分裂D的符号以及在实验中未测得的部分吸收光谱的值. 相似文献
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YAG:V2+激光材料晶格畸变及其EPR参量研究 总被引:6,自引:6,他引:0
利用Newman的晶场叠加模型,建立了晶体微观结构与电子顺磁共振(EPR)参量之间的定量关系.采用全组态完全对角化方法,对YAG:V2+晶体的局域晶格畸变及其EPR参量进行了系统的研究,结果表明:V2+离子掺入YAG晶体后,V2+离子的局域结构产生压缩三角晶格畸变,沿[111]晶轴方向V2+离子上方的三个O2-配体与下方的三个O2-配体均偏离[111]轴1.96°,从而成功地解释了YAG:V2+晶体的EPR参量.同时研究也表明,SS与SOO磁相互作用对EPR参量的贡献不可忽略. 相似文献
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利用提拉法多次生长了KMgF3∶Sm2+和KMgF3∶Sm2∶Li+晶体;在KMgF3∶Sm2晶体结构分析的基础上,通过测试和分析KMgF3∶Sm2+和KMgF3∶Sm2+∶Li+晶体的激发光谱、发射光谱以及衰减曲线,揭示了晶体的7 F0→5D0激发光谱中,680 ~ 682 nm范围内未被揭示的一个激发峰的产生机理.最后得出结论该激发峰是由Li+引起的HA色心,此结论通过355 nm紫外光照射对光谱的影响进一步得到了确认. 相似文献
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Dario Pasini Michele Zema Pierpaolo Righetti 《Journal of chemical crystallography》2007,37(8):537-541
The title compound crystallizes in the trigonal space group R-3, with unit-cell parameters: a = 23.261(4), c = 9.537(2) Å; λ(MoKα) = 0.71073 Å, V = 4469(2) Å3, and Z = 6. The structure has been solved by direct methods using X-ray diffraction techniques. The final reliability index for the computed structure is 0.0826 for 929 observed reflections and 121 refined parameters. Crown ether adopts an almost circular shape and macrocycles are piled up in a columnar arrangement forming tubular nanochannels. The channels are filled with guest CDCl3 molecules, characterised by rotational disorder. 相似文献
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The effect of ammonium malate on the growth rate, structural, optical, thermal, mechanical, dielectric properties, crystalline perfection and second harmonic generation (SHG) efficiency of ammonium dihydrogen phosphate single crystals grown by the slow cooling method has been investigated. The lattice parameters of the grown crystals were obtained by the single-crystal X-ray diffraction analysis. Fourier transform infrared studies confirm the functional groups of the crystals. UV–vis study shows that the transparency is increased much by the dopant. Thermal analysis was performed to study the thermal stability of the grown crystals. Vickers hardness measurements reveal the higher hardness of the doped crystals. Low dielectric losses were observed from the dielectric measurements for the doped ADP crystals. The high-resolution X-ray diffraction studies show that the crystalline perfection of the crystals is good. The relative SHG efficiency measurements revealed that the dopant has enhanced the efficiency. 相似文献
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Crystallography Reports - A geometrical and topological analysis has been performed, and self-assembly of the crystal structures of intermetallic compounds CsnMk (М = Na, K, Rb, Pt, Au, Hg,... 相似文献
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Crystallography Reports - The crystal structure of potassium, rubidium, cesium, and ammonium hydrophthalates is analyzed based on the data in the literature. A relationship between their structure... 相似文献
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Kozhemyakin G. N. Bryl O. E. Panich E. A. Dovgalyuk A. I. Savitskiy I. V. Yarmov A. A. 《Crystallography Reports》2019,64(2):337-341
Crystallography Reports - Gallium, indium, bismuth, and antimony nanoparticles were obtained by vacuum evaporation technique onto glass carbon substrates at an argon gas pressure of 6 × 103 Pa... 相似文献
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J. N. Lisgarten B. S. Potter C. Bantuzeko R. A. Palmer 《Journal of chemical crystallography》1998,28(7):539-543
The crystal and molecular structure of the antimalarial compound Artemisinin (formerly known as Qinghaosu), C15H22O5 has been determined by direct methods. Crystals are orthorhombic colorless needles, space group P212121, Z = 4. D
c = 1.299 g cm –3, with unit cell parameters a = 6.3543(9), b = 9.439(3), c= 24.066(4) Å. The molecule incorporates a fused ring system containing a six-membered ring C which includes an oxygen bridge and a peroxy-bridge. The ring C has a distorted boat conformation and the C - O - O - C torsion angle is 47.8(2)°. Rings A and D have symmetrical chair and distorted chair conformations, repectively. Ring junctions A/B, A/D, and C/D are cis, junction B/D is trans. All inter-molecular contacts are van der Waals. The absolute configuration of Artemisinin was determined from the refined value of the Flack x parameter. [The atomic coordinates given in a previous structure analysis, Crystal Structure and Absolute Configuration of Qinghaosu, Qinghaosu Research Group, Institute of Biophysics, Academica Sinica, Scientia Sinica, Vol. XXIII No. 3, 380 (1980), do not display the molecule in its absolute configuration.] 相似文献
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Arun K. Kota Gaurav Anand Suresh Ramakrishnan Liya L. Regel William R. Wilcox 《Journal of Crystal Growth》2006,290(2):319-333
Sessile drop experiments were performed on molten indium antimonide on clean quartz (fused silica) surfaces. A cell was constructed through which argon, helium, oxygen, hydrogen or a mixture of these was flowed at 600 °C. Some of the InSb was doped with 0.1% Ga. The surface tension σ of oxide-free molten InSb was smaller in Ar than in He, may have increased with increasing O2 in the gas, and was not influenced by Ga or H2. The contact angle θ on silica was higher in the presence of Ar, was lowered by O2, and was not influenced by H2 or Ga. The work of adhesion W and the surface energy σsv of the silica were higher in He than in Ar. The surface remained free of solid oxide only in flowing gas containing 0.8 ppm O2. This behavior is attributed to reaction of O2 at the surface of the melt to form In2O gas. When solid oxide formed on Ga-doped material, it was strongly enriched in Ga, with the Ga/In ratio increasing with the concentration of O2 in the gas.
Examination of published sessile-drop results for liquid metals and semiconductors on silica revealed that W and σsv were highest for reactive melts, in which SiO2 dissolves. For non-reactive melts, W and σsv were lower and θ higher in a gas than in a vacuum, regardless of whether the experiments had been carried out in sealed ampoules, a flowing gas, or dynamic vacuum. The implication is that the surface of silica was different in a vacuum than in a gas at 1 bar. 相似文献