Yb：YAG晶体中的荧光浓度猝灭现象

在Ｙｂ：ＹＡＧ晶体中发现浓度猝灭现象,对猝灭机制进行了分析研究,指出退火前晶体的荧光浓度猝灭现象主要由Ｙｂ＾２＋、色心和由此产生的晶格畸变所致高掺杂浓度时痕量稀土杂质离子的存在也将导致浓度猝灭,确定了Ｙｂ：ＹＡＧ晶体中Ｙｂ＾３＋的理想掺杂浓度。     

掺Yb双包层光纤激光器波长调谐输出

采用调节腔损耗以调节阈值的方法实现了掺Yb双包层石英光纤激光器的波长调谐输出 调谐范围达50nm 、步长约2nm 当损耗增大阈值升高时,激射波长向短波方向漂移.利用石英中Yb³⁺的能级结构和光谱特性对以上规律进行了定性解释.     

De–excitation of compound nuclei with A around 56: reduction of the emission barriers for protons and alpha particles

This paper contributes to the discussion on the phenomena of the enhanced emission of low–energetic charged particles during compound nuclei decay. The decay of compound nuclei ⁵²Fe, ⁵⁶Ni, and ⁵⁹Cu was studied. Energy spectra and emission angles of evaporated charged particles were measured in coincidence with gamma rays to determine the corresponding evaporation residue nucleus. Additionally, evaporation residue distributions were determined with the Munich rf recoil spectrometer. In this way, detailed channel–specific evaporation data were obtained for theoretical analysis. We extracted evaporation barriers and compared them with corresponding fusion barriers. The main result was revealed to be a lowering of the evaporation barrier for protons and alpha particles relative to the fusion barriers. But the observed effect is not as intensive as reported in recent studies. Received: 15 June 1998 / Revised version: 5 November 1998     

A new high-spin isomer in 145Sm

A new high-spin isomer in ¹⁴⁵Sm was observed by in-beam γ-ray spectroscopy with the reaction ¹²²Sn(²⁷Al,3np) at 127 MeV performed at the Nordball multi-detector array in Roskilde. The excitation energy of the isomer was determined to be E _x= 11147 keV, and using the generalized centroid-shift method its half-life was found to be T _1/2= (7.4 ± 1.0) ns. Received: 23 October 1998     

新型氮杂大环化合物的研究2: 四吡唑类卟啉大环化合物的合成 及配位性能

报道了几种四吡唑类卟啉大环化合物的合成及其对Ru^2^+离子的配位性能。结果表明,配体环中4个sp^2杂化N原子均参与对Ru^2^+配位,形成一个近似配位平面,另有两个相同或不同的轴向配体位于平面上下,形成稳定的八面体配位结构。根据轴向配体的配位稳定性可方便地将其进行交换。     

锌卟啉轴向配合物的光谱特性及配位二聚体分子内的能量传递

通过轴向配位作用构造了ZnTPP-H₂(m-py)TPP卟啉二元体系,研究了配位二聚体的可见吸收光谱和荧光发射光谱特性,考察了二聚体分子内的能量传递过程,观察到能量从激发态ZnTPP^*流向H₂(m-py)TPP。作为对比,研究了ZnTPP-py体系的可见吸收光谱和荧光发射光谱。轴向配位的吡啶引起了ZnTPP荧光光谱明显红移,没有分子内的能量转移过程发生。用吸收光谱和荧光光谱方法计算了加合反应的平衡常数,得到了基本一致的结果。     

Thermodynamic study of axial coordination reaction of zinc porphyrin with metal Schiff base and imidazole complex

A thermodynamic study is reported for the coordination reaction of ZnT ( m-X)PP derivatives (X = NO2, Cl, OCH3, H or CH3) with various ligands L (L= imidazole (Im), 2-methylimidazole (MeIm), clotrimidazole (CIM), imidazole-4-carboxaldehyde (4-CHOIm), unsymmetrical tetradentate copper Schiff base, CuIm(p-Cl), CuIm(p-Br), and nickel Schiff base, NiIm(p-Cl)), in dichloromethane solvent. Conversion of the four-coordinated ZnT( m-X)PP to the five-coordinated species is followed and isosbestic behavior is exhibited in the region among 450 and 700 run. The reaction of a copper(Ⅱ) or nickel(Ⅱ) imidazolate Schiff base with ZnT(m-X)PP results in the formation of an imidazolate bridged heterobinuclear complex. The stoichiometric number is unity for all axial ligands. The equilibrium constants were determined using the β band of ZnT( m-X)-PP in the 293-308 K range by the method of Rose and Drago. It increases with decrease in temperature, and △H0 < 0, △S0 < 0. The stronger the nucleophilic ability of the axial     

含DDQ^—的Phen,Bipy,En金属配合物的量子化学研究

含ＤＤＱ（２,３－Ｄｉｃｈｌｏｒｏ－５,６－ｄｉＣｙａｎｏｂｅｎｚｏｑｕｉｎｏｎｅ）的某些金属配合物由于具有较好的导电性能及特殊的磁性,在记录材料等领域具有广阔的应用前景而引起不少化学工作者的研究兴趣［１］。六十年代至今Ｂｒａｎｄｏｎ［２］、ｌｉｄａ［３］、Ｇｉａｌｍｏｔｔｉ［４］、Ｆｕｋｕｚｕｍｉ［５］、Ｍｉｌｌｅｒ［６］等为代表的一些化学家研究了与某些茂金属的氧化还原反应、电荷转移反应及产物光谱性质、磁学性质和导电性,并弄清了在这些电荷转移盐中ＤＤＱ不是以ＤＤＱ而是以ＤＤＱ形式出现。胡培植等…     

Some Polynuclear Coordination Compounds Precursors of Chromites Synthesis,Physicochemical Characterization and Thermal Stability

The polynuclear coordination compounds LnCr(tartrate)₃·nH₂O where Ln(III)=La-Er, obtained through a precipitation method, were characterized on the basis of elemental analysis, their electronic and vibrational spectra and magnetic susceptibility measurements. The possibility of obtaining chromites through the transformations of the polynuclear coordination compounds in the solid state was considered. The thermal decompositions of these compounds, studied by TG and DTA methods, were found to follow an almost uniform pattern. The decompositions occurred in six-eight steps. The first two steps involved dehydration, and the third the transformation of tartrate anions to oxalate, followed by conversion to carbonate and oxocarbonate intermediates. The final product in each case was LnCrO₃. A non-isothermal kinetic analysis of the first decomposition steps was performed, the most probable decomposition mechanism being selected and the kinetic parameters evaluated. The final products of the transformations were characterized. This revised version was published online in August 2006 with corrections to the Cover Date.     

4f轨道的成键性质

本文介绍了目前国内外关于镧系配合物４ｆ轨道成键行为研究的现状与进展,对其理论和研究方法进行了系统的总结,归纳了４ｆ轨道的成键规律。