[OsⅣ（N）（NH3）4]（CF3SO3）3电化学还原过程的原位FTIR光 …

运用原位ＦＴＩＲＳ,ＵＶ／Ｖｉｓ和电化学方法研究了乙腈溶液中「ＯｓⅣ（Ｎ）（ＮＨ３）４」（ＣＦ３ＳＯ３）３在ＧＣ和Ｐｔ电极上的还原过程。结果首次在Ｐｔ电极上检测到桥氮物种υ（Ｎ≡Ｎ）的红外谱峰,位于２０１９和１９７０ｃｍ＾－１附近,分别指认为「Ⅲ,Ⅱ」和「Ⅱ,Ⅱ」混合价桥氮俄络合物。为进一步探讨桥氮偶联过程提供了新的谱学数据。     

Growht and defects in YbxY1—xAl3（BO3）4 crystals

YbxY1-xAl3(BO3)4(x=0.1,0.07 and 0)crystals have been grown by the flux method.The growth defects of YbxY1-xAl3(BO3)4 crystals were detected by X-ray topography.It is found that the perfcetion of YbYAB crystal with low Yb dopant is better than that with high Yb dopant.In Yb0.1Y0.9Al3(BO3)4 crystal,growht bands,growth boundaries,grown-in dislocations and inclusions were observed.Howver,the densities of growth defects for Yb0.07Y0.93Al3(BO3)4 and YAl3(BO3)4 are low and no obvious inclusions are observed in these crytals.In addition,growth twins wrer detected in YbxY1-xAl3(BO3)4 crystal by using the chemical etching method.It is found that the growth twins occur frequently in Yb0.01Y0.9Al3(BO3)4 crystal whereas no growth twin appears in YAl3(BO3)4 crystal. Based on the experimental observations,the formation mechanism of growth twins is discussed.In the meantime,the effective measures for reducing the growth twins and defects are proposed.2001 Elsevier Science B.V.All rights reserved.     

在N2中[VnCr3—n（μ3—O）（μ—O2CCH3）6（THF）3]X[n=0—3,X=Cl^—1,ClO4^—,（VO5）0.5^—]及[VnFe3—n（μ3—O）（μ—O2CCH3）6（THF）3]X（n=0—3,X=Cl^—1）

The reaction behavior of the title complexes have been investigated by means of in situ IR in nitrogen atmosphere. It has been found that they enabled the acetic acid to convert to acetone and methane in different temperatures. The results indicate that the sequence of the ketonization reaction activity for the clusters was [V3OAT] > [VFe2OAT], [V2CrOAT] > [Fe3OAT], [VCr2OAT] > [Cr3OAT] [OAT = (mu 3-O) (mu-O2CCH3)6 (THF)3], and the sequence of the methanation reaction activity for the clusters was [Cr3OAT] > [VCr2OAT], [V2CrOAT] > [V3OAT] > [VFe2OAT], [Fe2OAH]. The ketonization reaction activity of [Fe3OAT] were obviously lower than that of [Fe3OAH] [OAH = (mu 3-O) (mu-O2CCH3)6 (H2O)3] and the methanation reaction activity of [Cr3OAT] were also much lower than that of [Cr3OAH]. The difference between [Fe3OAH], [Cr3OAT] and [Fe3OAH], [Cr3OAH] mentioned above were discussed.     

纳米（Li2AO4）1—x—（ZrO2）x固体电解质陶瓷

用溶液凝胶共混法制备了纳米级的Ｌｉ２ＳＯ４－ＺｒＯ２复合固体电解质陶瓷。在复合陶瓷中，Ｌｉ２ＳＯ４、ＺｒＯ２的晶粒平均尺寸分别为４５、２７ｎｍ。晶粒尺寸的纳米化在材料中引入了大量的界面结构和表面结构。研究了掺不同量的纳米ＺｒＯ２第二相对Ｌｉ２ＳＯ４相变温度、相变行为及体系电导的影响，在纳米ＺｒＯ２作用下，Ｌｉ２ＳＯ４的相变温度可以降低１４０℃。在适当配比时，在５４０℃其离子电导可达到０．２Ｓ／ｃｍ     

Na（4D）＋Na（3S）=Na（4F）＋Na（3S）碰撞能量转移截面

利用双光子吸收，将Ｎａ（３Ｓ）原子激发到４Ｄ态，测量了Ｎａ（４Ｄ）＋Ｎａ（３Ｓ）＝Ｎａ（４Ｆ）＋Ｎａ（３Ｓ）碰撞能量转移截面，因为直接由４Ｆ→３Ｄ的荧光不能探测，所以检测３Ｄ→３Ｐ级联荧光讯号。结合基态钠原子密度的测量，给出了截面值σ４Ｄ→４Ｆ－１．３×１０＾－１４±２８％（ｃｍ＾２）。     

Stereodynamics study of the H′（^2S） ＋ NH（X^3∑-） 〉 N（4S） ＋ H2 reaction

The stereodynamics and reaction mechanism of the H′（^2S） ＋ NH （X^3∑^-） → N（^4S） ＋ H2 reaction are thoroughly studied at collision energies in the 0.1 eV-1.0 eV range using the quasiclassical trajectory （QCT） on the ground 4A″ potential energy surface （PES）. The distributions of vector correlations between products and reagents P（φr）, P（φr） and P（φr,φr） are presented and discussed. The results indicate that product rotational angular momentum j′ is not only aligned, but also oriented along the direction perpendicular to the scattering plane; further, the product H2 presents different rotational polarization behaviors for different collision energies. Furthermore, four polarization-dependent differential cross sections （PDDCSs） of the product He are also calculated at different collision energies. The reaction mechanism is analyzed based on the stereodynamics properties. It is found that the abstraction mechanism is appropriate for the title reaction.     

Sr_3Ga_2Ge_4O_（14）晶体中Cr~（3＋）和Cr~（4＋）吸收光谱

采用提拉法生长了掺Ｃｒ的Ｓｒ３Ｇａ２Ｇｅ４Ｏ１４低温石榴石结构型单晶，测量了它的吸收光谱及其偏振特性，系统描述了该晶体在可见和近红外波段各吸收带的特征，指出Ｃｒ在此晶体晶格中主要存在两种价态Ｃｒ３＋和Ｃｒ４＋，Ｃｒ４＋在近红外的吸收将影响到Ｃｒ３＋的发光。     

Anomalous magnetostrictive effects in （La1—xTbx）2／3Sr1／3 MnO3

A series of (La_{1-x}Tb_x)_{2/3}Sr_{1/3}MnO_3 polycrystalline samples has been studied by means of x-ray diffraction, magnetostriction, and thermal expansion measurements. It has been found that this series undergoes a phase transition from a rhombohedral to an orthorhombic form at the doping level x≈0.20 at room temperature accompanied by an anisotropic magnetostriction up to －50×10^{-6} under a magnetic field of 1T. The linear and volume magnetostrictions vary with chemical composition, even change sign. At T=80K, the magnetostrictions for the samples of x=0.20 and 0.40 exhibit different behaviours. The sample of x=0.20 has positive volume and linear magnetostrictions and a negative anisotropic magnetostriction, while the sample of x=0.40 has an opposite behaviour. The magnitude of volume magnetostriction for both the samples is essential (～10^{-4}) at T=80K under a magnetic field of 4T. We conclude that these anomalous effects are due to the charge delocalization and the structural phase transition between orthorhombic and rhombohedral forms induced by the applied magnetic field.     

用色散荧光研究NH2（A^2A1）转动态—态传能

利用脉冲染料激光制备ＮＨ２（Ａ＾２Ａ１）单一转动能态Σ（０，９，０）３０３，在分子束条件下研究它的态－态转动传能至Σ（０，９，０）５０５，１０１和△（０，９，０）６２５，５２３，４２３，３２１，２２１各转动能态的相对截面。结果表明：转动跃迁│△Ｎ│＞２几率较小，│△Ｎ│愈小，传能截面愈大，而且同一电子振动态内传能最有效，且向下跃迁快于向上跃迁。分析荧光谱可以看出碰撞前后转动能极的对称性不变，这是单