低速Xe~(q+)(4≤q≤20)离子与Ni表面碰撞中的光辐射

实验中测量了0.38V_(Bohr)(460 keV)高电荷态Xe~(q+)(4≤q≤20)离子轰击高纯Ni表面发射的400-510 nm光谱.实验结果包括NiⅠ原子谱线,NiⅡ离子谱线,以及入射离子中性化发射的XeⅠ,XeⅡ和XeⅢ谱线.研究了谱线XeⅡ410.419,XeⅢ430.444,XeⅡ434.200,XeⅡ486.254,NiⅠ498.245,NiⅠ501.697,NiⅠ503.502,NiⅠ505.061和NiⅠ508.293 nm的光子产额随着入射离子电荷态的变化.结果表明,入射离子中性化和溅射Ni原子发射谱线的光子产额随着入射离子电荷态的增加而增加,其趋势与入射离子势能一致.     

Ln(Ⅲ)-Ni(Ⅱ)与双水杨醛缩乙二胺席夫碱异核配合物的合成与波谱

合成了双水杨醛缩乙二胺席夫碱(SALEN)与镍的配合物Ni₃(SALEN)₂(NO₃)₆·H₂O及镧系镍的异核配合物Ln₂Ni₃(SALEN)₆(NO₃)₁₂·H₂O(Ln=La,Nd,Sm,Gd,Yb,Y).以紫外、红外光谱、磁化率,特别是¹H NMR及EPR波谱等方法研究了它们在组成、结构和配位等方面的异同.Gd-Ni-SALEN配合物的EPR谱表明其在低温THF中呈"单峰效应".文中讨论了配合物在不同溶剂中峰宽的相对关系、配合物晶体场强度及Gd³⁺周围局部对称性问题.     

BeAl6O10晶体中的Cr^3＋发光中心

铬激活的BeA1_6O_(10)(BHA)晶体中Cr~(3+)离子形成多种发光中心,给出复杂的发光.发光谱中包含着荧光寿命为几十微秒至几毫秒不同的光谱成分,本文用Chrono光谱法分离子这些重迭的成分,辩认出三种铬中心——两种强场中心,Cr(Ⅰ)和Cr(Ⅱ),一种低场中心,Cr(Ⅲ).并且给出了它们占据的格位.一个单胞里可能的铬格位共有40个.其中,24个畸变了的八面体格位属于Cr(I)型中心;8个畸变较小近乎正八面体的格位属于Cr(Ⅱ)型中心;另外8个格位具有次近邻微扰结构,属于Cr(Ⅲ)型中心.Cr(Ⅲ)给出宽带发射.     

DYNKIN'S EMBEDDING METHOD AND SUBALGEBRA CHAINS OF U(6)⊃SU(3)*

Use Dynkin's embedding method to find out the generators of two subalgebra chains of U(6)⊃SU(3).     

THE DYNAMICAL U(15/30)SUPERSYMMETRIES IN NUCLEI AND ITS SU(3)LIMIT

In this paper, g-boson is introduced into the interacting boson-fermion model (IBFM) of nuclei,and the single fermion is supposed to occupy 5 single-particle orbits with the angular j=1/2.3/2.5/2,7/2,9/2 individually.we find that there exist dynamical U(15/30) supersymmetries in nerclei. First the supersymmetry U(15/30) and its group chains obtained by its reduction to Spin (3) are studied and then two SU(3) limits are discussed in detail. Finally the two SU(3) limits are applied to nuclei ²³⁵₉₂U₁₄₃ and ¹⁸⁵₇₄W₁₁₁ respectively, the results are quite good.     

The Unitarity of the W(3) Algebra from SU(3) Parafermion

We express the vacuum expectation value of the SU(3)k parafermion fields by that of two bosons and SU(3)_k current algebra. When k = 1,2,3, the SU(3)_k current algebra becomes an inner product of a unitary representation, and T(z), W⁽³⁾(z) are equivalent to "quasiself-adjoint" operators in this represen tation.     

HYPERON DECAYS IN THE CNIRAL BAG MODEL

In terms of the chiral bag model and SD(3) Skyrme wave-functions of baruons, we investigate Δ⁺ →Pγ (SU(2)) and Σp⁺ → Pπ⁰ (SU(3) case) hyperon decays. We have found that for Δ⁺ →Pγ the Skyrme contribution is more important whereas in Σp⁺ → Pπ⁰ the quark content transition dominates.     

QQqq Four-Quark Bound States in Chiral SU(3) Quark Model

The possibility of QQqq heavy-light four-quark bound states has been analyzed by means of the chiral SU(3) quark model, where Q is the heavy quark (c or b) and q is the light quark (u, d, or s). We obtain a bound state for the bbnn configuration with quantum number J^P=1⁺,I=0 and for the ccnn (J^P=1⁺,I=0) configuration, which is not bound but slightly above the D^*D^* threshold (n is u or d quark). Meanwhile, we also conclude that a weakly bound state in bbnn system can also be found without considering the chiral quark interactions between the two light quarks, yet its binding energy is weaker than that with the chiral quark interactions.     

A new solution of d = 11 supergravity with internal isometry group SU(3) × SU(2) × U(1)

A new solution of the bosonic sector of D = 11 supergravity is presented in which the internal space has the topology CP² × S² × S¹ and the internal isometry group is SU(3) × SU(2) × U(1).     

Particle-hole excitations in the interacting boson model (III): The O(6)-SU(3) coupling

We apply the group theoretical concepts of the EIBM, an extension of the interacting boson model where a distinction is made between particle and hole bosons, to the particular situation of two coexisting systems in the same nucleus exhibiting the O(6) (regular states) and SU(3) (intruder states) symmetries. Besides giving evidence that such a coexisting set of states could well be applicable to the Pb region, we discuss the “global” symmetry properties of the above model. We also concentrate on mixing between the otherwise coexisting symmetries and point out how to make more realistic calculations. We discuss, at large, the experimental evidence in the Pb region for intruder analog multiplets.     

SU(6)对称性理论中的弱相互作用

本文提出了SU(6)对称性理论中的一个弱相互作用中间玻色子方案。基本假定是:(1)中间玻色子归为SU(6)群的不可约表示21;(2)弱流归为正规表示35;从而(3)s波及p波半弱相互作用分别归为表示21中的(3^*,1)部分及表示15中的(3^*,3)部分。则除了△I=1/2规则以外,由此得出的有效超子非轻子作用在s波(宇称破坏)振幅都分给出三个求和规则,在p波(宇称守恒)振幅部分给出一个求和规则,这些关系看来和实验符合得较好。     

The Branching Rules for SU(2N)⊃(SU(N)⊃O(N)⊃O(3))⊗SU(2) and the Highest Weight States for SU(N) and O(N)

Simple analytical recurrent formulae of the branching rules for group chain SU(2N)⊃(SU(N)⊃O(N)⊃O(3))⊗SU(2) are obtained. The highest weight states for the irreducible representations [2^al^b] or {nS} of group SU(N) and for the irreducible representations (2^α1^β) or (υS) of group O(N) are constructed respectively     

Li+离子掺杂对红色发光材料Y2(W,Mo)O6:Eu3+发光性能的影响

采用高温固相法制备了荧光粉Y2-x(W,Mo)O6:Eu3+,xLi+,利用X射线衍射仪和电子扫描显微镜对样品的结构和形貌进行了表征,并利用荧光光谱法分析了样品的光谱特性.首先在Y2WO6中掺入少量的Mo6+离子,掺入Mo6+后增加了原Y2WO6:Eu3+的激发光谱在近紫外光区的吸收,扩展了激发光谱的谱宽,但却使Y2W...     

Adjustable half-skyrmion chains induced by SU(3) spin-orbit coupling in rotating Bose-Einstein condensates

The ground state properties of the rotating Bose-Einstein condensates (BECs) with SU(3) spin-orbit coupling (SOC) in a two-dimensional harmonic trap are studied. The results show that the ferromagnetic and antiferromagnetic systems present three half-skyrmion chains at an angle of 120° to each other along the coupling directions. With the enhancement of isotropic SU(3) SOC strength, the position of the three chains remains unchanged, in which the number of half-skyrmions increases gradually. With the increase of rotation frequency and atomic density-density interaction, the number of half-skyrmions on the three chains and in the regions between two chains increases gradually. The relationships of the total number of half-skyrmions on the three chains with the increase of SU(3) SOC strength, rotation frequency and atomic density-density interaction are also given. In addition, changing the anisotropic SU(3) SOC strength can regulate the number and morphology of the half-skyrmion chains.     

Theoretical Studies of g Factors and Defect Structures for Cubic, Tetragonal, and Orthorhombic Fe^＋ Centers in Alkali Halides MX （M=Li, Na; X = F, C1）

The EPR 9 factors for cubic, tetragonal and orthorhombic Fe^＋ centers in alkali halides MX （M= Li, Na; X = F, CI） are calculated from second-order perturbation formulas of g factors based on cluster approach for 3d^7 ions in three symmetries. From calculations, the g factors of these Fe^＋ centers in MX crystals are reasonably explained and the defect structural data for the tetragonal and orthorhombic Fe^＋ centers are estimated. The results are discussed.     

Sum rules for the baryon20, baryon20′ and meson 16-plet coupling constants in broken SU (4) and SU (3) symmetry

Sum rules for the coupling constants for D (20), B (20′) and P (16) are given taking into account first order breaking of SU (4) and SU (3) symmetries. The D (20) and B (20′) contain the usual 3/2⁺ baryon decuplet and 1/2⁺ baryon octet of SU (3), while the P (16) contains the usual pseudoscalar octet of pions, etc. These sum rules generalize the decuplet → octet + octet sum rules of broken SU (3 to a broken SU (4) symmetry scheme, in particular the charm SU (4) for hadrons. It is pointed out that, of the many sum rules, it may be possible to check some of them experimentally (see Section 5) and thus provide a test for an underlying SU (4 symmetry for strong interactions.     

Na2Ca6La2(PO4)6F2:Eu3+的荧光和结构的局部对称性

稀土Eu3+离子的荧光谱线的数目、位置和强度与其所处的周围环境对称性有明确的联系。为了测定La3+离子在Na2Ca6La2(PO4)6F2相中所处格位的对称性,合成样品时,适量掺杂Eu3+离子,得到Na2Ca6La2-x(PO4)6F2:Eux红色荧光体。研究此种发光体的荧光光谱性质,能够证实La3+在Na2Ca6La2(PO4)6F2中处于两种不同的对称格位(D3h和C6)。     

SU(6) model for odd-odd nuclei (OTQM/IBOM) and boson-aligned phase diagram inO(6) limit

We introduce the SU(6) model IBOM/OTQM for odd-odd nuclei and discuss the bands in O(6) limit. Bands are characterized by a particular type of phase correlations in the wave functions and exhibit splitting of the SU(3) analogs of Gallagher-Moszkowski bands.