Total Routhian Surface Calculations on Hf Isotopes

The two-dimensional total routhian surface calculations have been carried out to stud）, the triaxial superdeformed structure of a neutron-rich nucleus ^173 Hf firstly. In particular the effects of the rotational frequency ω and pairing-energy gap parameter A are discussed in detail in the course of shaping its triaxial superdeformation; additionally the neutron-shell correction energy is analyzed with emphasis in the confirmed triaxial superdeformed nucleus ^173Hf. Finally, more systematical results have been investigated for some confirmed superdeformed nuclei experimentally and a few predicted triaxial superdeformed nuclei theoretically with quadropole deformation ε2 ≈0.4 and triaxial deformation γ≈20° or 30° in the Z = 72 region.     

Description of Rotation Bands in^157,158Er at Ultrahigh Spin

Properties of the four rotation bands, ^157Er（1,2） and ^15SEr（1,2）, at ultrahigh spin are investigated within the supersymmetry scheme including many-body interactions and possessing the SO（5） （or SU（5）） symmetry on the rotational symmetry. Quantitatively good results of the 7-ray energies and the dynamical moments of inertia in the rotation bands in ^157 Er and ^158 Er at ultrahigh spin are obtained. We theoretically predict that the competition between the anti-pairing and pairing effects may exist in ^157 Er（1,2） and ^158Et（2） bands states. In ^158Er（1） band state, the favourepairing effects may exist and the SO（5） （or SU（5）） symmetry play a dominant role. There may be sphere coexisting with headecupole deformed in ^158Et（1） rotation band state.     

Doublet bands at borders of A ≈ 130 island of chiral candidates: Case study of ~(120)I

Positive-parity doublet bands were reported in ~(120)I. Based on these, we discuss the corresponding experimental characteristics, including rotational alignment, and re-examine the corresponding configuration assignment.The self-consistent tilted axis cranking relativistic mean-field calculations indicate that the doublet bands are built on the configuration πh_(11/2)■νh_(11/2)~(-1). By adopting the two quasiparticles coupled with a triaxial rotor model, the excitation energies, energy staggering parameter S(I), B(M1)/B(E2), effective angles, and K plots are discussed and compared with available data. The obtained results support the interpretation of chiral doublet bands for the positive-parity doublet bands in ~(120)I, and hence identify this nucleus as the border of the A ≈ 130 island of chiral candidates.     

Vibronic instabilities in a system with nonrigid electron bands

The vibronic dynamical lattice destabilization of a gapped two-band system with moving upper band bottom is investigated in one, two and three dimensions. The second order electron energy renormalization leading to possible destabilization has been calculated for various characteristic physical dispositions. The position of the chemical potential in the upper band near the gap edge promotes the destabilization. The dimensionality of the system does not change the general trends in the behavior of the destabilization. However, in low dimensional cases the chemical potential entering the singularity in the density of states enhances the speed of destabilization rapidly.     

β-Tetra-brominated meso-tetraphenylporphyrin: A conformational study and application to the Mn-porphyrin catalyzed epoxidation of olefins with tetrabutylammonium oxone

X-ray crystallographic studies have shown that the free base β-tetra-brominated meso-tetraphenylporphyrin (H₂TPPBr₄) has a slightly ruffled structure with the dihedral angles of 70.1–79.2° between the phenyl groups and the porphyrin mean plane. The N(pyrrole)–N(pyrrolenine) distance is very similar to that of the standard planar porphyrins. The decreased N–H bond length of H₂TPPBr₄ with respect to that of meso-tetraphenylporphyrin (H₂TPP) seems to be due to the weaker intramolecular hydrogen bond of the former relative to the latter caused by the electron-withdrawing effects of the β-bromine substituents. The large red shifts of the Soret and Q(0,0) bands of H₂TPPBr₄ in comparison with those of H₂TPP, in spite of the nearly planar porphyrin core of the compound, also may be explained on the basis of the electron-withdrawing effects of the bromine atoms. Oxidation of styrene, the para-substituted derivatives and cyclooctene with tetrabutylammonium oxone in the presence of catalytic amounts of β-tetra-brominated meso-tetraphenylporphyrinatomanganese(III) acetate immediately gives the epoxide as the sole product. Terminal double bonds and unconjugated ones are less reactive than the conjugated double bonds and show lower selectivities. Catalytic activity of the electron-deficient Mn(H₂TPPBr₄)OAc dramatically depends on the Co-catalytic activity of the nitrogen donors as the axial base. The best axial bases are the nitrogenous donors with mixed σ- and π-donor ability to the metal centre.     

Mössbauer study of the vibrational anisotropy and of the light-induced population of metastable states in single-crystalline guanidinium nitroprusside

M?ssbauer studies were performed on single crystals of guanidinium nitroprusside with different orientations of their principal crystallographic axes (a, b, c) with respect to the incident radiation. The markedly anisotropic Lamb-M?ssbauer factor f _LM , i.e. f _LM ^(a) = 0.118(8), f _LM ^(b) = 0.174(8), f _LM ^(c) = 0.202(8) is in contrast to that of nitroprussides with inorganic anions. The observed anisotropy is ascribed to the anisotropic vibrational mean-square displacement of the nitroprusside anions as a whole which is due to the specific packing of both, anions and cations, as well as the very weak chemical bonding between the ions, typical only for guanidinium nitroprusside. The vibrational anisotropy of iron atoms in barium nitroprusside that has been observed by X-ray structural investigations has a different origin and therefore does not result in an anisotropic Lamb-M?ssbauer factor. We have also investigated metastable states in guanidinium nitroprusside that have been populated by means of incoherent irradiation from light-emitting diodes. With a specific orientation of the guanidinium nitroprusside single crystal a population of the metastable states up to 26% could be achieved. Populations of comparable size on lithium, sodium and potassium nitroprussides have only been reached using coherent laser irradiation. Received 15 December 1998 and Received in final form 3 March 1999     

含螯合型双膦配体羰基Fe（Ⅱ）化合物紫外—可见光谱性能的研究

地双膦配体羰基铁化合物的紫外－可有收峰作发属,讨论了确定金属有机化合物ＵＶ－ＶＩＳ、Ｍ－ＬＣＴ带的方法,研究了卤素对Ｍ－ＬＣＴ带,ｄ－ｄ跃迁吸收的影响以及ＣＴ带的浓度效应。     

Problems of the electronic structure of nonmetals in a wide energy region of fundamental absorption (review)

The article surveys the main unsolved problems of the electronic structure of nonmetals in a wide energy region of fundamental absorption. Udmurtia State University, 71, Krasnogeroiskaya Str., Izhevsk, 426034, Russia. Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 66, No. 3, pp. 299–315, May–June, 1999.     

Electronic structure of C60 films

A complete set of fundamental optical functions of fullerite (C₆₀) films in energy ranges of 2.5–5.0 and 4.0–9.0 eV is calculated using the known spectra of the imaginary and real parts of the dielectric constant. An integrated spectrum of the dielectric constant is decomposed into elementary components. Three basic parameters of each component (the maximum and halfwidth energies and oscillator strength) are determined. Based on the known theoretical calculations of fullerite zones, a scheme of the nature of these components of the dielectric constant is suggested. Udmurt State University, 71, Krasnogeroiskaya Str., Izhevsk, 426034, Russia. Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 66, No. 2, pp. 227–232, March–April, 1999.     

超形变原子核全同带的判断与角动量增量顺排量子化

给出了一个新的从能量角度判断超形变带全同带的方法,并运用这种方法分析了100多条超形变带.给出了全同带数目随判断参数的变化关系.还引进了量子化区间的概念,从统计角度分析角动量增量顺排的量子化问题,得出了全同带增量顺排随判据加严而趋向于量子化的性质,而正常形变全同带则不具有这一性质.讨论了新方法与粒子转子模型之间的关系.