以一组统一的高斯函数为基函数的双原子分子的Hartree-Fock-Roothaan波函数(Ⅱ)——H2和第一列元素的同核双原子体系A2,A2~±和A2

采用文献的一组统一的doublezeta收缩高斯型函数为基函数,从头计算H₂和第一列元素的同核双原子体系的电子波函数和轨道能量、总能量等物理量。电子态包括同核体系的基态A₂,一些低激发态A₂~*和正负离子态A₂~±,A表示周期表中Li到F的各种元素。计算限于闭壳层电子组态或只带一个未填满的开壳层电子组态。作为例子,报道了H₂和几种基态A₂的电子波函数表。 关键词：     

Structure instability of A2Al2B2O7 (A=K, Na) crystals

A theoretical study on the stabilities of the crystal structures of K₂Al₂B₂O₇ (KABO) and Na₂Al₂B₂O₇ (NABO) has been carried out using density functional theory with generalized-gradient corrections. All structures have been optimized by minimizing the total energies with respect to lattice constants and to the atomic coordinates within the unit cell. In the case of KABO, the structure with space group P321 always takes energy advantage over the whole volume range studied, whereas on both volume expansion and contraction, the original NABO structure becomes unstable, taking a structure transition from its space group to the P321 space group of KABO structure. The theoretical predictions were well realized in the experimental results on the structure changes of the (K_1−xNa_x)₂Al₂B₂O₇ solid solution system.     

Defect luminescence of ordered perovskites A2BWO6

This paper describes luminescence spectra of ordered perovskites of the type A₂BWO₆. The compounds A₂MgWO₆ show two different emission bands. From the Raman spectra of Ba₂MgWO₆ and Ba₂CaWO₆ and from luminescence experiments on Ba₂Na_0.8W_1.2O₆ and Ba₂Ca_0.95Na_0.04W_1.01 it is concluded that there is a slight deviation from complete ordering between the Mg²⁺ and W⁶⁺ ions in A₂MgWO₆.     

Changes in wetting properties of silica surface treated with DPPC in the presence of phospholipase A2 enzyme

Wetting properties of silica plates contacted with dipalmitoylphosphatidylcholine (DPPC) or DPPC/enzyme (phospholipase PLA₂) in NaCl solution were determined by thin layer wicking and with a help of Washburn equation. The wicking experiments were performed both for bare plates and the silica plates precontacted overnight with the probe liquid saturated vapors the silica plates, as well as untreated and DPPC (or DPPC/enzyme) treated. Adsorption of DPPC on original silica plates increases a bit hydrophobic character of silica surface in such a way that hydrocarbon chains are directed outwards and the polar part towards the silica surface. However, after the enzyme action the products of DPPC hydrolysis by PLA₂ (palmitic acid and lysophosphatidylcholine) increase again hydrophilic character of silica surface (an increase in acid-base interactions, ).The changes of silica surface wettability are evidently dependent on the time of enzyme contacting with DPPC in NaCl solution. Although, the changes of total surface free energy of silica after treatment with DPPC/enzyme solution are minor about 2-6 mJ/m², the changes of the electron-donor () and Lifshitz-van der Waals () component of the surface free energy are noticeable. Despite, these results are somehow preliminary, it seems that thin layer wicking method is an interesting tool for investigation of the effect of adsorbed DPPC on hydrophobicity/hydrophilicity of silica surface and influence of enzyme PLA₂ action.     

异常双钙钛矿A_2BB′O_6氧化物的多铁性

异常钙钛矿结构氧化物是多铁性材料家族中研究得最为广泛的体系之一.本文从ABO_3钙钛矿结构出发,引入了异常A_2BB′O_6双钙钛矿材料,首先简要介绍了传统及异常A_2BB′O_6双钙钛矿氧化物的结构特点;然后讨论了A_2BB′O_6多铁性材料的研究进展,包括A位为Mn,Ni等过渡金属离子的极性磁体多铁性材料和A_2CoMnO_6(A=Lu,Y,Yb,Lu)以及Mn_2FeSbO_6等第II类多铁性材料;最后,在以上基础上展望了异常A_2BB′O_6双钙钛矿多铁性研究中存在的问题及新型多铁性材料研究的方向.     

A study of A2 and g resonance production in π−p→K−K0p

We present the results and the analysis of a high-statistics experiment to study A₂ and g production in the reaction π^?p→K^?K_S⁰p at 10 GeV/c. In each resonance region we perform a moment analysis of the data, and from the moments we determine the production amplitudes as a function of t. We find A₂ production proceeds dominantly by natural-parity (pomeron and f) exchange. We compare A₂ and diffractive K¹ (1420) production. We find g production proceeds by π and ω exchanges; we determine the $\text{g}\text{→}\text{K}\text{K}$ branching ratio.     

Amphoteric exciton trapping by 3d-impurities in A2B6 semiconductors

It is shown that the neutral deep level state of transition metal impurity in A₂B₆ semiconductors plays a role of amphoteric localization centre for the excitons: it can capture either electron or hole to the d-shell leaving either hole or electron in a loosely bound hydrogenlike orbit respectively. The physical properties of both excitonic states are compared and the possibility to interpret in these terms the optical spectra of ZnS(Se) doped by Ni and Co is discussed.     

Raman scattering study of the phase sequence in A2BX4 halides

Raman spectra of Cs₂ZnI₄ single crystal have been measured in different scattering orientations covering the successive phase transitions down to 68 K. Two second order anomalies at around ice temperature (270 K) and at ～ 92 K are observed. The anomaly around ice temperature exhibits the features of a normal-incommensurate transition evidenced by softening of a low-lying lattice phonon whose frequency decreases as the transition temperature is approached from below whereas the latter one appears to arise from usual structural distortions.     

A1 g phonons in YBa2Cu3O7 by first-principles atomic-force calculations

We report on ab-initio frozen-phonon calculations for the five A_1g Raman-active-modes of YBa₂Cu₃O₇ atq=0. The determination of the equilibrium positions of the atoms Ba, Cu(2), O(2), O(3), O(4) as well as of phonon frequencies and respective eigenvectors is based on the calculation of atomic forces within the LAPW-method. The general agreement between our results and experimental structural data and phonon frequencies is good. Deviations are discussed in connection with the local-density approximation.     

3c-SiC中深杂质能级的A1,T2对称波函数

本文采用文献[1—4]所发展的在位缺陷势格林函数方法,计算了3c-SiC中深能级的A₁,T₂对称波函数。第一次给出了波函数随杂质态能量E的变化趋势,和电子占据距缺陷中心最近邻的几个壳层的几率。并给出数量级与实验相符的3c-SiC:B的超精细结构常数的理论值。 关键词：     

ϱ and A2 amplitudes in K±N charge exchange using fixed t analyticity

Amplitudes corresponding to ? and A₂ quantum number exchanges in K^±N charge exchange scattering are obtained from data in the few GeV region using an analysis based on fixed t analyticity in the form of fixed t dispersion relations and finite-energy sum rules. Comparisons are made with amplitude analyses at 6 GeV/c and some specific high-energy models.     

Amplitudes for ϱ and A2 Regge exchanges in δ production processes

In δ production processes like $\text{π}{}^{\mathrm{+}}\text{p}\text{→ π}{}^0\text{δ}{}^{\mathrm{++}}\text{,}\text{K}{}^{\mathrm{+}}\text{p}\text{→}\text{K}{}^0\text{δ}{}^{\mathrm{++}}\text{,}\text{K}{}^{\mathrm{?}}\text{n}\text{→}\text{K}{}^0\text{δ}{}^{\mathrm{?}}$, exchange degeneracy breaking between ? and A₂ Regge poles is shown to be present in all s-channel helicity amplitudes including the double-flip one. Once. the dominance of two among four amplitudes and SU(3) invariance are assumed, the amplitudes are obtained in a rather model-indenpendent way. The peculiar feature of these amplitudes are analyzed and in particular some evidence for universality in the impact parameter representation is pointed out. Possible explanations are proposed.     

Modulation of the A1 resonance

A model is outlined for isolating the effects of final state interactions in an amplitude leading to three final pions. The method accounts for rearrangements among ?π and ?π states, producing a factor-of-2 fluctuation in the 1⁺ intensity below the A₁ mass. It follows that this effect should cause a modulation of the A₁ resonance.     

Temperature dependence of the A2 vibration modes in α-quartz

The infrared lattice bands which correspond to the A₂ modes of α-quartz, are analyzed by means of the classical oscillator model. The observed dependence of the classical parameters on temperature allows to think that non-linear effects occur by approaching the α→β phase transition.     

A measurement of the branching ratios of the A2− meson produced in 3.9 GeV/cπ−ϱ interactions

We have measured the branching fractions of the A₂^? meson, produced in the reaction π^?p → pA₂^? at 3.9 GeV/c incident momentum. The rates for the ηπ and K$\text{K}$ modes relative to ?π are 0.211 ± 0.044 and 0.056 ± 0.014, respectively. The upper limit for the η′π mode is 0.056 at the 90% confidence level. We have also looked for an ωππ decay of the A₂^? and our data are consistent with a rate of 0.10 ± 0.05, relative to ?π.     

Measurement of the A1-modes reflectivity of BaTiO3

Previous polarized infrared reflectivity spectra of BaTiO₃ were unable to show the expected differences between the A₁ and E phonons. This can be explained by the small penetration of light polarized perpendicularly to the ferroelectric axis in the LO-TO range of the lowest E phonon, where only the crystal surface determines the reflection of light. We show that with an adequate etching of a mono-domain single-crystal it is possible to obtain good quality spectra for both polarizations.     

τ→ν3π and the A1 resonance

We consider the possibility that the family group may be a spontaneously broken continuous global symmetry. In the context of grand unification, the couplings of the associated Goldstone bosons to fermions can be sufficiently suppressed so as to satisfy the phenomenological bounds. For a maximal family symmetry this requires a large number of Higgs fields.     

High yield preparation of silver nanowires by CuCl2-mediated polyol method and application in semitransparent conduction electrode

High yield preparation of silver nanowires (AgNWs) was prepared by polyol method. In this developed polyol process, uniform AgNWs have been successfully synthesized at higher yield by introducing CuCl₂·2H2O, when ethylene glycol is used as the solvent and reductant while poly vinyl pyrrolidone (PVP) is used as the capper agent. Then Ag thin films were made by screen printing using silver nanowires and nanoparticles as semitransparent conduction electrodes. The test results indicated that the electrical resistivity could be as low as 0.091 Ω/□, when the transparence rate can reach 45–46%, which shows great promise in the improvement of conductive antireflection coating.