(XB2)2(X=Al, Be, Na, Mg)团簇的密度泛函研究

用密度泛函理论(DFT)的杂化密度泛函B3LYP方法在6-31G*基组水平上对(XB2)2(X=Al,Be,Na,Mg)团簇各种可能的构型进行几何结构优化,预测了各团簇的最稳定结构.并对最稳定结构的电子结构、振动特性、成键特性和电荷特性等进行了理论研究.结果表明,团簇的几何结构大多是平面结构,通常是B-B键和B-X键共存,较少出现X-X键.团簇的稳定结构中通常是几个呈负电性的B原子形成一个负电中心,而其他B原子和X原子处在端位,且显正电性.     

~(59)Co(n,p)~(59)Fe,~(59)Co(n,α)~(56)Mn,~(59)Co(n,2n)~(58)Co反应截面的测量

本实验用活化法测量了中子能量在12.8MeV到17.8MeV的~(59)Co(n,p)~(59)Fe,~(59)Co(n,α)~(56)Mn,~(59)Co(n,2n)~(58)Co三个反应道的反应截面值,实验的测量误差在3.3％—6.9％范围内. 本文还计算了反应截面测量误差的协方差矩阵,并将实验测量值与理论计算值进行了比较.另外,还对上述三个反应道的截面进行编评,给出了推荐的激发曲线.     

Electron spin resonance spectrum of radicals in γ-irradiated trimethyl phosphite: P(OMe)4, HP(OMe)3, P(OMe)2, (MeO)3P-P(OMe)3 + and H2COP(OMe)2

The infra-red spectra of 1 : 1 complexes between benzene and chlorine, bromine, and iodine chloride have been studied, with the complexes isolated in a nitrogen matrix at 20 K. The results are interpreted as evidence for an oblique complex structure, with the halogen molecule interacting mainly with one of the C=C bonds.     

Realisations of quantum GL p,q(2) and Jordanian GLh,h′(2)

The quantum group GL _p,q(2) is known to be related to the Jordanian GL_h,h(2) via a contraction procedure. It can also be realised using the generators of the Hopf algebra G _r,s. We contract the G _r,s quantum group to obtain its Jordanian analogue G _m,k, which provides a realisation of GL_h,h(2) in a manner similar to the q-deformed case.     

~(186)W(d,p)~(187)W,~(186)W(d,2n)~(186)Re,~(nat)Fe(p,x)~(56)Co和~(nat)Ti(a,x)~(51)Cr反应激发函数评价

考虑特征γ射线分支比、衰变常数和标准截面等修正,对带电粒子引起的核反应~(186)W(d,p)~(187)W,~(186)W(d,2n)~(186)Re,~(nat)Fe(p,x)~(56)Co和~(nat)Ti(a,x)~(51)Cr的激发函数进行了研究。全面收集了这些反应激发函数的实验测量数据,对这些实验数据进行了分析处理,应用数学方法对分析处理后的实验数据进行了拟合。经过评价,给出了50 Me V以下~(186)W(d,p)~(187)W,~(186)W(d,2n)~(186)Re,~(nat)Fe(p,x)~(56)Co和~(nat)Ti(a,x)~(51)Cr反应激发函数的推荐值。     

~(55)Mn(α,n)~(58m,g)Co,~(55)Mn(α,2n)~(57)Co和~(55)Mn(α,α′n)~(54)Mn反应的激发函数

用活化法和迭靶技术,在入射α粒子能量从10.4到26.5MeV范围内,测量了~(55)Mn(α,n)~(58m,g)Co、~(55)Mn(α,2n)~(57)Co和~(55)Mn(α,α′n)~(54)Mn反应的截面,并同激子模型理论计算作了比较,结果表明在上述反应中存在平衡前发射反应机制。     

~(100)Mo(n,2n)~(99)Mo,~(96)Mo(n,p)~(96)Nb和~(92)Mo(n,α)~(89m+g)Zr反应截面测量

本文报告了在E_n=13.40—14.79MeV中子能区用活化法以~(27)Al(n,α)~(24)Na截面为中子注量标准测得的~(100)Mo(n,2n)~(99)Mo,~(96)Mo(n,p)~(96)Nb和~(92)Mo(n,α)~(89m+g)Zr的反应截面,中子能量是用铌锆截面比法测定的。文中将实验测量值与理论计算值进行了比较,还对上述三个反应的截面进行了编评,给出了推荐的激发曲线。     

(p,n)和(p,2n)反应激发函数的系统学研究

从普朗克(Planck)黑体辐射公式和实验测量数据出发,采用唯象的方法提出了包含两个可调参量,入射质子能量从阈能到150MeV,靶核质量数在44相似文献   

(XB2)2(X=Al, Be, Na, Mg)团簇结构与性质的密度泛函研究

用密度泛函理论(DFT)的杂化密度泛函B3LYP方法在6-31G·基组水平上对(XB2)2(X=Al,Be,Na, Mg)团簇各种可能的构型进行几何结构优化,预测了各团簇的最稳定结构.并对最稳定结构的电子结构、振动特性、成键特性和电荷特性等进行了理论研究.结果表明,团簇的几何结构大多是平面结构,通常是B-B键和B-X键共存,较少出现X-X键.团簇的稳定结构中通常是几个呈负电性的B原子形成一个负电中心,而其他B原子和X原子处在端位,且显正电性.     

Tensor Force Manifestations in ab Initio Study of the 2H(d, γ)4He, 2H(d, p)3H, and 2H(d, n)3He Reactions

The ²H(d, γ)⁴He capture reaction and the ²H(d, p)³H and ²H(d, n)³He transfer reactions at very low energies are studied in an extended microscopic cluster model with a realistic nucleon–nucleon force. Our results show that the tensor force in realistic interactions plays an essential and indispensable role to reproduce the very low-energy astrophysical S factor of these reactions.     

Tensor force manifestations in ab initio study of the 2H(d,γ)4He, 2H(d,p)3H, and 2H(d,n)3He reactions

The (2)H(d,p)(3)H, (2)H(d,n)(3)He, and (2)H(d,γ)(4)He reactions are studied at low energies in a multichannel ab initio model that takes into account the distortions of the nuclei. The internal wave functions of these nuclei are given by the stochastic variational method with the AV8' realistic interaction and a phenomenological three-body force included to reproduce the two-body thresholds. The obtained astrophysical S factors are all in very good agreement with the experiment. The most important channels for both transfer and radiative capture are identified by comparing to calculations with an effective central force. They are all found to dominate thanks to the tensor force.     

Structural, thermal, and electrical properties of (100?x) ZrO2 (x) Bi2O3 compound

Composition (100?x) ZrO₂ (x) Bi₂O₃ (x?=?15, 20, 25) is synthesized by solid-state reaction method to study the effect of Bi₂O₃ doping on ZrO₂. The as-prepared samples are characterized by various methods. The X-ray diffraction pattern of all these samples exhibits three phases, namely, m-ZrO₂, ??_III-Bi₂O₃, and ??-Bi₂O₃. The differential thermal analysis curves do not show any phase transition/decomposition, which clearly indicated the stabilization of ??-Bi₂O₃ phase. The conductivity changes in all the samples are discussed in terms of different phase formations and their volume fractions. The microstructural and energy dispersive analyses indicate the presence of different phases. A maximum conductivity at high temperature (800?°C) was observed for the x?=?25 composition, i.e., ???=?4.21?×?10^?2 S/cm.     

Spectroscopic Properties and Electronic Structure of (L-Glutamato)(2, 2′-Bipyridine) copper(II)

Cu(L-glu)(bpy)(L-glu = L-glutamato; bpy = 2, 2′-bipyridine) was prepared. Its electronic absorption spectrum and photoacoustic spectrum were recorded at room temperature. They were compared with each other and compared quantitatively with ligand field theory(LFT) and the radical wave function of non-free ions^[1–3]. Therefore, the electronic structure was also investigated with its spectrum behaviors and PLFT^[1–3].     

粉末晶体(ZrO2)x(Bi2O3)1-x(x=1.0, 0.97) 晶体结构分析

为了确定ZrO2和(ZrO2)0.97(Bi2O3)0.03的晶体结构和原子热振动各向同性温度因子B，对该粉末晶体进行X射线衍射实验，建立了晶体结构模型，进行晶体结构分析。首先，采用共沉淀法和高温固相烧结法制备了纳米氧化锆ZrO2和(ZrO2)0.97(Bi2O3)0.03粉末晶体，接着，使用X射线测试仪对两种样品进行了衍射实验（XRD），利用Rietveld 精修方法的 RIETAN-2000程序对所得实验结果进行了晶体结构分析，获得了晶体结构参量和原子热振动各向同性温度因子B。通过Maximum Entropy Method（MEM）解析得到了粉末晶体(ZrO2)x(Bi2O3)1-x(x=1.0，0.97)的等高电子密度分布可视化图谱。结果表明，(ZrO2)0.97(Bi2O3)0.03的晶胞体积比ZrO2的晶胞体积大分别为140.6850 Å3和140.5637Å3；ZrO2晶体的原子热振动各向同性温度因子B(Zr)、BO(1)、BO(2)和 B（Bi）分别为0.690、0.269、 0.178 和 0 Å2，(ZrO2)0.97(Bi2O3)0.03晶体的分别为0.460 、0.583 、0.121 和0.581 Å2。 确定了(ZrO2)0.97(Bi2O3)0.03的晶体结构属于单斜晶系，实现了等高电子密度分布三维（3D）和二维（2D）的可视化，进一步确定了晶体结构和原子位置。     

(n,n)-(2n, 0)碳纳米管异质结的扭转力学特性

相近直径的锯齿型和扶手椅型碳纳米管可以共轴组合形成5-7碳环交替出现的柱形对称异质结. 本文利用分子动力学方法研究了直径相近且等长锯齿型和扶手椅型碳纳米管形成的(n, n)-(2n, 0)结在扭转过程中的扭矩和轴向应力随扭转角度的变化规律以及应力传递过程. 研究发现, (n, n)-(2n, 0)结扭转应变在达弹性限度内不会产生轴向应力, 该效应对基于碳纳米管扭转特性的纳米振荡器件的设计具有重要意义.     

关于介分子离子(αp,μ~-)和(αp,2μ~-)

应用ACQM理论和方法研究介分子离子(αp,μ~-)和(αp,2μ~-).发现(αp,μ~-)的基态(X~2Σ~+)为排斥态;(αp,2μ~-)为束缚态,平衡核间距R_e=0.0078bohr,能量极小值E=-551.78a.u.     

RECENT PROGRESS OF(e,2e) SPECTROSCOPY

Recent progress of(e,2e)spectroscopy,or Electron Momentum Spectros-copy(EMS),on laser excited oriented atoms,large bio-organic moleculesand thin films is reviewed.     

Spectroscopic Properties of Cu(L-met)2, Cu(DL-met)2, Cu(L-ala)2 and Cu(DL-ala)2˙H2O and Qualitative Explanations to the Magnetism and Relative Ordering of the One-Electron Energy Levels.

Electronic absorption spectra and photoacoustic spectra of four copper(II)-amino acid complexes of formulas Cu(L-met)˙(1). Cu(DL-met)˙(2). Cu(L-ala)x(3) and Cu(DL-ala)˙-H₂O(4)(L-met=L-methioninato;DL-met=DL-methioninato;L-ala=L-alaninato DL-ala=DL-alaninato) were recorded and the results are discussed quantitatively with respect to llgand field theory and the radical wave function of a non-free copper(II) ion. The relationship between the maximum absorption peak in PAS and magnetic properties is also discussed. Lastly, a qualitative explanation on the senquence of splitting energy in going from regular octahedral to strongly elongately and slightly tetragonally distorted octahedral around each copper(II) center is proposed.     

Magnetic and transport properties of single crystal LnRu(2)Al(10) (Ln?=?Pr, Gd, Yb)

Single crystals of LnRu(2)Al(10) (Ln?=?Pr, Gd, Yb) have been grown using the self-flux method, their structure has been determined by single crystal x-ray diffraction, and their magnetic and electronic transport properties have been studied. LnRu(2)Al(10) are members of the Y bFe(2)Al(10) structure type with space group Cmcm. PrRu(2)Al(10) displays paramagnetic behaviour down to 13.2?K, at which temperature it enters a non-magnetic singlet ground state, with a large paramagnetic Curie-Weiss temperature of -?49.8(14)?K. GdRu(2)Al(10) orders antiferromagnetically at 15.5?K. Y bRu(2)Al(10) is a Pauli paramagnet indicating that the Yb is divalent. The properties of these three analogues are compared with LnM(2)Al(10) (M=Fe, Ru, Os).