RbⅧ—NbⅪ离子n=4complex跃迁谱线、波长和振子强度

用HXR方法计算了类锌等电子序列RbⅧ-NbⅫ离子n=4complex组态能级，通过对各能级值沿等电子序列的变化规律分析，找出了ⅦE随Zc变化的一种新的拟合公式，运用此公式和我们自己设计的FOR-TRAN程序对上述组态各能级值进行了系统的拟合计算，给出了4s^2-4s4p,4s4p-4s4d跃迁谱线波长和相应的振子强度。     

RbⅧ-NbⅫ离子n＝4 complex跃迁谱线、波长和振子强度

用HXR方法计算了类锌等电子序列RbⅧ-NbⅫ离子n＝4 complex组态能级.通过对各能级值沿等电子序列的变化规律分析,找出了ΔE随Zc变化的一种新的拟合公式,运用此公式和我们自己设计的FORTRAN程序对上述组态各能级值进行了系统的拟合计算.给出了4s2-4s4p,4s4p-4s4d跃迁谱线波长和相应的振子强度.     

硫酸氢铵高压下相变研究

由于铁电材料在科学研究领域的重要应用,功能铁电材料的设计和机理研究一直是国内外的研究热点。材料的性能离不开结构研究,为了更好的认识和理解一种典型铁电材料-硫酸氢铵的结构和相行为,研究了17GPa压强下硫酸氢铵的高压拉曼光谱。在压力作用下,绝大多数的拉曼谱线向高波数方向移动,并且有两个特征拉曼谱带的强度发生很大的变化(1 018和3 183cm~(-1)),表明硫酸盐与铵离子正四面体的电子云密度发生重构。根据频移-压强曲线关系,得出了硫酸氢铵在6和10.5GPa附近分别存在一阶相变。根据高压下S=O伸缩振动谱带的变化规律,发现了不同相区间氢键的相反作用规律。为AHSO_4系列铁电材料压力作用下结构变化规律提供一定的研究基础。     

Laser Microprobe Mass Analysis of NH4 ReO4, AgReO4 and Al (ReO4)3

The laser microprobe mass analyzer (LAMMA) is a recently developed mass spectroscopic technique for both organic and inorganic microanalysis. LAMMA analysis involves laser ionization of the sample material followed by mass separation in a time of flight (TOF) mass spectrometer. The present application of LAMMA illustrates the characterization of three inorganic perrhenates: NH₄ReO₄, AgReO₄ and Al(ReO₄)₃. Results clearly show the value of LAMMA for inorganic mass spectrometry, in this study the most useful data originated in the negative-ion mass spectra.     

Incommensurability and metastability problems in NH4HSeO4 and ND4DSeO4: A reinvestigation of phase diagrams

Abstract

X-ray and neutron diffraction results on NH₄HSeO₄ and ND₄DSeO₄ are reported. Direct evidence of an incommensurate phase sandwiched between the monoclinic high-temperature phase (space group B2) and the low-temperature ferroelectric lock-in phase k = ? (space group P1) has been obtained in NH₄HSeO₄. The phase situation is more complicated in ND₄DSeO₄, where an incommensurate phase is found sandwiched between the B2 phase and a lock-in phase k = ¼ and where a phase in which several modulations coexist has been discovered in between the two lock-in phases k = ¼ and k = ?. The non-equilibrium processes, also present in ND₄DSeO₄, have been identified. All these results have clarified the situation about the phase diagram.     

CsLiSO4/NH4LiSO4 system investigated by EPR

The single crystals of CsLiSO₄ and the solid solutions Cs _x (NH₄)_{(1? x )}LiSO₄ have been investigated using the EPR technique. Two kinds of vanadyl doped samples were considered – as-grown from the aqueous solutions of appropriate compounds and after a thermal treatment. It has been established that in as-grown crystals the EPR spectra of vanadyl ions were very complex due to the presence of more than one paramagnetic site in the lattice. At least two such sites were identified and spin Hamiltonian parameters were calculated for all the sites. After annealing the crystals at about 400?K, a significant decrease in the intensities of the EPR lines of VO²⁺ complexes was observed. In well-annealed samples the complexity of the EPR spectra has been found to disappear. Additionally, the third kind of vanadyl complexes were created during this treatment. It has also been shown that the EPR spectra of Cr³⁺ ions in CsLiSO₄ could be observed without any additional sample treatment reported in literature like an irradiation or thermal decomposition. It was established that the VO²⁺ and Cr³⁺, being sensitive to structural phase transition in the CsLiSO₄, can be used as a probe for the structural changes in the CsLiSO₄/NH₄LiSO₄ system.     

Impedance spectroscopy analysis of LiZnVO4 and LiMgVO4

A comparative LiZnVO₄ and LiMgVO₄ conductivity study was done from room temperature to 500 °C and at frequencies from 42 to 1 MHz. The impact of moisture absorption to the materials’ conductivity was investigated. It was shown for LiZnVO₄ that moisture absorption is responsible for the decrease of the compound’s conductivity as the material is heated up to 150 °C. The LiZnVO₄ bulk activation energy value was calculated to be 1.20 eV. Two grain boundary activation energy values were calculated for the LiZnVO₄, 0.59 eV at the lower temperature range and 1.37 eV at the higher temperature range. An explanation for the existence of these two values was given. Both materials’ plots of the loss factor (tanδ) versus frequency at different temperatures were found to display a peak, and the modulus master curves present a scaling behavior that suggests non Debye type conductivity relaxation and ion migration via hopping.     

4-氨基-4'-氯二苯甲酮的合成及光谱表征

对硝基苯甲酰氯和氯苯在无水三氯化铝催化下 ,生成 4 硝基 4’ 氯二苯甲酮。以二硫化钠为还原剂 ,将其还原成重要有机中间体 4 氨基 4’ 氯二苯甲酮。通过多因素正交实验 ,确定了最佳工艺条件为 :反应温度 92℃ ,反应时间 2 5h ,4 硝基 4’ 氯二苯甲酮 :Na2 S2 =1∶1 7(mol) ,回收率为 85 80 % ,纯度为98 0 8% ,熔点 177～ 179℃。采用元素分析 ,1H ,13 C核磁共振波谱 ,红外光谱及质谱法表征了目标化合物的分子结构 ,并对化合物红外光谱吸收峰及核磁谱带进行了归属分析。阐明了质谱主要碎片离子的裂解途径。此研究可为无致癌性的禁用染料中间体替代品开发提供依据。     

Exafs studies of LiYF 4 -LiREF 4 solid solutions

In this work we are investigating dopant environments in LiYF 4 -LiREF 4 (RE=rare-earth cations) solid solutions, via EXAFS. The main aims are to identify the local environmental symmetry and the average lattice distortion as a function of the concentration and the type of the RE ion. LiY 1 m x RE x F 4 (RE=Gd or Lu) (0< x <1) single crystals were grown by the Czochralski technique under argon or CF 4 atmosphere, crystal-pulling rates were 0.6-1 v mm/h for <100>-oriented boules, with 8-25 v rpm rotation rates. Most of the crystals were also codoped with 2.7 v mol% of neodymium in the melt. EXAFS measurements were performed in transmission and fluorescence modes in the synchrotron XAS line of the LNLS, Campinas, Brazil, in and above the L III absorption edges of the RE ions. The samples were prepared as powder films, for the transmission mode measurements, and as powder or single crystals for fluorescence mode measurements. The WINXAS program was used for data reduction and fitting, and the FEFF6 package was used for the simulations of the spectra. The EXAFS oscillation curves were obtained by standard procedure.     

类镓等电子序列ZrX—RhXV离子的4s^24p—4s^24d,4s^24p—4s4p^2,4s^24 …

本文对类镓等电子序列ＧａＩ－ＸｅＸＸＩＶ离子４ｓ＾２４ｐ、４ｓ＾２４ｐ、４ｓ＾２４ｄ、４ｓ４ｐ＾２、４ｐ＾３和４ｓ＾２５ｓ组态组级结果和组态相互作用了理论分析，找出沿等电子序列的变化规律。     

TcⅪ离子的4s~24p~3—4s4p~4跃迁

通过对KrⅣ—MoⅩ离子4s4p~4组态能级结构的组态相互作用理论分析,找出了其沿等电子系列变化的规律性。在此基础上预言了TcⅪ离子的4s4p~4组态能级。结合前人对4s~24p~3组态的研究结果,进一步计算了4s~24p~3—4s4p~4跃迁的谱线波长和振子强度。     

Persistence of superconductivity in magnetically ordered SmRh4B4

Measurements of the thermal conductivity and the electrical resistivity between 50 mK and 4 K in zero magnetic field and in fields exceeding the superconducting critical field H_c2 indicate the persistance of bulk superconductivity in magnetically ordered SmRh₄B₄.     

Anisotropic transport properties of U4Cu4P7

The electrical resistivity of U₄Cu₄P₇ for the current flowing in the basal plane of this tetragonal antiferromagnetic compound has been measured from 2 to 1000 K. Contrary to the case where the current flows along thec axis, we find an increasing resistivity with increasing temperature over the whole temperature range. This ferromagnetic-like behavior in the basal plane and the antiferromagnetic-like behavior perpendicular to it, is explained with the complex magnetic structure of the compound. The Hall effect forB parallel to thec axis shows an antiferromagnetic-like temperature dependence. The ordinary part of the Hall effect in the paramagnetic phase gives in an one-band model a carrier concentration of 0.7 holes per uranium atom, which is quite unique in uranium compounds by its sign and which results from the presence of two kinds of uranium atoms with different bonding, valence, magnetic moment and exchange. Quantitative differences between various samples of U₄Cu₄P₇ are related to a mixed-layer stacking polytype of U₄Cu₄P₇ and UCuP₂ units.