Uranium is a member of Actinides and plays important role in nuclear science and technology. Electronicand structural investigations of actinide compounds attract major interest in science. The electronic structure an...Uranium is a member of Actinides and plays important role in nuclear science and technology. Electronicand structural investigations of actinide compounds attract major interest in science. The electronic structure andchemical bonding of coffinite USiO_4 are investigated by X-ray Absorption Fine Structure spectroscopy (XAFS). U L_3-edge absorption spectrum in USiO_4 is compared with U L_3-edge spectra in UO_2 and UTe due to their different electronicand chemical structures. The study presents XANES (x-ray Absorption Near-Edge Structure) and Extended XAFS(EXAFS) calculations of USiO_4 thin films. The full multiple scattering approach has been applied to the calculation ofU L_3 edge XANES spectra of USiO_4, UO_2 and UTe, based on different choices of one electron potentials according toUranium coordinations by using the real space multiple scattering method FEFF 8.2 code.展开更多
The growth and ordering of {5,10,15,20-tetrakis（4-bromophenyl）porphyrinato}nickel（II） （NiTBrPP） molecules on the Au（111） surface have been investigated using scanning tunnelling microscopy, X-ray absorption, c...The growth and ordering of {5,10,15,20-tetrakis（4-bromophenyl）porphyrinato}nickel（II） （NiTBrPP） molecules on the Au（111） surface have been investigated using scanning tunnelling microscopy, X-ray absorption, core-level photoemission, and microbeam low-energy electron diffraction. When deposited onto the substrate at room temperature, the NiTBrPP forms a well-ordered close-packed molecular layer in which the molecules have a flat orientation with the porphyrin macrocycle plane lying parallel to the substrate. Annealing of the NiTBrPP layer on the Au（111） surface at 525 K leads to dissociation of bromine from the porphyrin followed by the formation of covalent bonds between the phenyl substituents of the porphyrin. This results in the formation of continuous covalently bonded porphyrin networks, which are stable up to 800 K and can be recovered after exposure to ambient conditions. By controlling the experimental conditions, a robust, extended porphyrin network can be prepared on the Au（111） surface that has many potential applications such as protective coatings, in sensing or as a host structure for molecules and clusters.展开更多
文摘Uranium is a member of Actinides and plays important role in nuclear science and technology. Electronicand structural investigations of actinide compounds attract major interest in science. The electronic structure andchemical bonding of coffinite USiO_4 are investigated by X-ray Absorption Fine Structure spectroscopy (XAFS). U L_3-edge absorption spectrum in USiO_4 is compared with U L_3-edge spectra in UO_2 and UTe due to their different electronicand chemical structures. The study presents XANES (x-ray Absorption Near-Edge Structure) and Extended XAFS(EXAFS) calculations of USiO_4 thin films. The full multiple scattering approach has been applied to the calculation ofU L_3 edge XANES spectra of USiO_4, UO_2 and UTe, based on different choices of one electron potentials according toUranium coordinations by using the real space multiple scattering method FEFF 8.2 code.
文摘The growth and ordering of {5,10,15,20-tetrakis（4-bromophenyl）porphyrinato}nickel（II） （NiTBrPP） molecules on the Au（111） surface have been investigated using scanning tunnelling microscopy, X-ray absorption, core-level photoemission, and microbeam low-energy electron diffraction. When deposited onto the substrate at room temperature, the NiTBrPP forms a well-ordered close-packed molecular layer in which the molecules have a flat orientation with the porphyrin macrocycle plane lying parallel to the substrate. Annealing of the NiTBrPP layer on the Au（111） surface at 525 K leads to dissociation of bromine from the porphyrin followed by the formation of covalent bonds between the phenyl substituents of the porphyrin. This results in the formation of continuous covalently bonded porphyrin networks, which are stable up to 800 K and can be recovered after exposure to ambient conditions. By controlling the experimental conditions, a robust, extended porphyrin network can be prepared on the Au（111） surface that has many potential applications such as protective coatings, in sensing or as a host structure for molecules and clusters.
