XPS STUDY ON RARE-EARTH PHTHALOCYANINE COMPLEXES

The rare earth monophthalocyanine complexes, LnPcCl and LnPc(OAc)2 (Ln = Tb, Ho, Tm, Lu, Pc=Phthalocyanine, OAc = Acetate), were synthesized. The electronic structures of the complexes have been studied by means of XPS. The experimental results of binding energies for the complexes indicate that the bonds of the complexes have a certain covalent character depending on L-->Ln charge transfer. This L-->Ln charge transfer process of phythalocyanine complexes differs from that of crown ether complexes. Both coordination and substitution are included in the former case, but only coordination in the latter. Phthalocyanine ring is an electrophilic group and its electronegativity is large. So, the O1s binding energies of coordinating oxygen atoms of acetate in LnPc(OAc)2 are larger than those of Ln(OAc)3. The magnitude of valent charge delocalized from ligand onto metal atom is dependent on electronegativity, coordination number, valence state and so on. Because coordination number of Ln in LnPc(OAc)2 is larger than that in LnPcCl and electronegativity of Clin LnPcCl is larger than that of O in LnPc(OAc)2, the Ln4d5/2 binding energies of LnPc (OAc)2 are less than those of LnPcCl.

STUDY OF BIMETALLIC COMPLEXES OF RARE-EARTH LITHIUM - SYNTHESIS AND CRYSTAL-STRUCTURE OF THE (LACL)DME(MU-2-CL)5(MU-3-CL) (LA.DME)LI(THF)2

The reaction between LaCl_3 and LiCl in THF at room temperature, with hexane as precipitant and glycol dimethyl ether as complexing agent, has been studied. A complex with the composition of (LaCl)DME(μ_2-Cl)_5(μ_3-Cl)(La·DME)Li(THF)_2 has been synthesized, its structure was studied by single crystal X-ray diffraction technique. The diffraction intensities were collected at about —100℃. The complex belongs to the triclinic space group P1 with α=11.123(3), 6=16.564(5), c=8.653(3)A, α=95.16(3), β=...

SYNTHESIS AND VIBRATIONAL SPECTRUM STUDIES OF RARE EARTH COMPLEXES WITH CYCLOHEXANE CARBOXYLIC ACID

The solid state complexes of trivalent lanthanid, yttrium and scandium with cyclohexane carboxylic acid have been isolated and characterized by IR and Raman spectroscopy. It was found that there are only chelated carboxylate groups in the scandium complex and that there are the chelated, bridged and chelate-bridged carboxylate groups in other rare earth complexes. The former is a mononuclear complex and the latter is a polynuclear polymer. The RE—O coordinate bonds possess the characters of convalent ionic ...

Vertical transferring process of rare elements in coral reef lagoons of Nansha Islands, South China Sea

The vertical fluxes and vertical transferring forms of 18 rare elements were studied for the first time in the coral reef ecosystem of Nansha Islands, South China Sea, by deploying sediment traps, The results showed that the vertical transferring flux of most of the measured rare elements in Yongshu lagoon were higher than that in Zhubi lagoon. The vertical transferring forms of rare elements were mainly in the carbonate form, but Ta, As, Th mainly in the ion-exchange form, Ag in iron-manganese oxide form and Sb in the organic matter + sulphide form. None of the 18 rare elements was transferred mainly in the form of detritus silicate to sea floor. This proved that rare elements originating from the earth's crust were redistributed in sinking particulates after they were brought into ocean. The relation between the fluxes and surface seawater temperature (STT) was also studied. The sensitivity of rare elements to SST was in order: Rb>V>As>Ti>U>Zn>Sb>Hf>Ag>Cs.

Rare-earth-doped silica microchip laser fabricated by sintering nanoporous glass

We report a new method for fabricating rare-earth-doped silica glasses for laser materials obtained by sintering nanoporous silica glasses impregnated with rare-earth-doped ions. The fabricated materials have no residual pores and show good optical and mechanical properties. Good performance from a Nd3+-doped silica microchip laser operating at 1.064 mum is successfully demonstrated, suggesting that the fabricated silica glasses have potential for use as active materials for high-power solid-state lasers. (C) 2005 Optical Society of America.

Proposal for the direct optical detection of pure spin currents in semiconductors

We suggest a different practical scheme for the direct detection of pure spin current by using the two-color Faraday rotation of optical quantum interference process (QUIP) in a semiconductor system. We demonstrate theoretically that the Faraday rotation of QUIP depends sensitively on the spin orientation and wave vector of the carriers, and can be tuned by the relative phase and the polarization direction of the omega and 2 omega laser beams. By adjusting these parameters, the magnitude and direction of the spin current can be detected.

Orbital magnetization in semiconductors

National Natural Science Foundation of China 60821061 60776061 10604010 60776063

Compatibility relationship among reaction equilibria, equivalence principle of reaction approaches, and silicon contamination in semiconductors

This paper discovers some shortcomings in the algorithm for the incorporation of Si into GaAs in the GaAs VPE process. These faults arise from neglecting a link, the compatibility relationship, in chemical thermodynamics. The meaning of said relationship is as follows: In an equilibrium complex system, each species can only contribute one and the same quantity (its equilibrium quantity) to the different equilibria of the various reactions involving it; yet even under this restriction, every equilibrium constant is satisfied, and all the reaction equilibria coexist compatibly in the system. Only by adding the relationship can the equilibrium theory for the complex system be complete. This paper also tells its position in chemical thermodynamics. Such a compatibility concept directly leads to an equivalence principle: In a complex system, a certain species can usually be simultaneously formed by many chemical reactions; when the system has reached equilibrium under fixed environmental conditions, the equilibrium quantity of said species calculated according to each chemical equation of these reactions will be equal and the various reaction approaches will be equivalent, provided that for all the reactants and all the other products of these reactions their equilibrium quantities in the system are respectively taken as corresponding knowns for the calculations, which is extremely useful for seeking a functional relation among the species' equilibrium quantities in a system (Si contamination is one of the examples). Under the guidance of those arguments, the various schools' algorithms for the Si contamination can be uniformized and simplified, and the contamination quantity relation between Si and O, two very important impurities, is found.

Magnetoexcitonic optical absorption in semiconductors under strong magnetic fields and intense terahertz radiation in the Voigt configuration

The magnetoexcitonic optical absorption of a GaAs bulk semiconductor driven by a terahertz (THz) field is investigated numerically. The method of the solution of the initial-value problem, in combination with the perfect matched layer technique, is used to calculate the optical susceptibility, with Coulomb interaction, Landau quantization, and THz fields involved nonperturbatively. It shows that there appear replicas and sidebands of magnetoexciton of different Landau levels, which greatly enrich the magneto-optical spectrum in the presence of a driving THz field. Copyright (C) EPLA, 2008.

Excitonic optical absorption in semiconductors under intense terahertz radiation

The excitonic optical absorption of GaAs bulk semiconductors under intense terahertz (THz) radiation is investigated numerically. The method of solving initial-value problems, combined with the perfect matched layer technique, is used to calculate the optical susceptibility. In the presence of a driving THz field, in addition to the usual exciton peaks, 2p replica of the dark 2p exciton and even-THz-photon-sidebands of the main exciton resonance emerge in the continuum above the band edge and below the main exciton resonance. Moreover, to understand the shift of the position of the main exciton peak under intense THz radiation, it is necessary to take into consideration both the dynamical Franz-Keldysh effect and ac Stark effect simultaneously. For moderate frequency fields, the main exciton peak decreases and broadens due to the field-induced ionization of the excitons with THz field increasing. However, for high frequency THz fields, the characteristics of the exciton recur even under very strong THz fields, which accords with the recent experimental results qualitatively.