The SCF-Xα-SW molecular orbital calculations were carried out on the modelcompounds of binuclear and trinuclear gold(Ⅰ)using starting potential of Au atom and the Watson sphere.The energy level order of the frontier...The SCF-Xα-SW molecular orbital calculations were carried out on the modelcompounds of binuclear and trinuclear gold(Ⅰ)using starting potential of Au atom and the Watson sphere.The energy level order of the frontier orbital of a binuclear gold model compound is in agreement with the experimental result.The calculated ionization potential of the binuclear model compound is consistent well with the photoelectron spectrum of Au (Me)(PMe_3).The metal-metal interactions are discussed.The calculated electronic absorption spectra of binuclear and trinuclear gold(Ⅰ)are basically in agreement with experimental results.展开更多
Electronic structures of REBaCuO (RE=La, Pr, Nd, Sm, Gd, Dy, Ho and Er)systems were calculated by means of SCF-Xα -SW methods. Results show that there is an inner-orbitcoupling for these oxide superconductor systems....Electronic structures of REBaCuO (RE=La, Pr, Nd, Sm, Gd, Dy, Ho and Er)systems were calculated by means of SCF-Xα -SW methods. Results show that there is an inner-orbitcoupling for these oxide superconductor systems. The inner-orbit coupling was resulted from theinteraction of two electronic orbits of RE 5p and O 2s, since they have similar energy state levelsand relatively larger orbital electronic clouds. Compared with experimental facts, it is also foundthat the overlap in space between the two orbits has a similar tendency to T_c and the number ofenrolling electrons has a close relation to J_c, therefore, the influence of inner-orbit coupling onsuperconductivity could not be overlooked.展开更多
In the ZrO_2-based ceramic systems doped with different oxides (Y_(2)O_3, MgO and Al_(2)O_3), the behaviors of electronic and ionic conductivity have been investigated by the quantum chemical SCF-X_α-SW method. The r...In the ZrO_2-based ceramic systems doped with different oxides (Y_(2)O_3, MgO and Al_(2)O_3), the behaviors of electronic and ionic conductivity have been investigated by the quantum chemical SCF-X_α-SW method. The results of the electronic energy spectra and local state density of atoms show that, for the ZrO_2 system doped with Al_2O_3, the energy gap near the Fermi energy level becomes smaller, which implies that the electronic conductivity increases. Since the binding energy between Al and O atoms is increased, the energy for oxygen vacancy migrating is enhanced and the ionic conductivity decreases. In the M_xO_y-doped ZrO_2 systems, due to the doping effect of Al_2O_3, MgO and Y_2O_3, the ionic conductivity increases successively, and the electronic conductivity decreases successively. The cal- culation results are in agreement with that of references and experience.展开更多
The electronic structure of γ′ phase containing Mg in nickel-based superalloy is inves-tigated with SCF-X_n-SW method. Based on the model cluster presented for the strengtheningmechanism of Mg in γ′ phase, the ene...The electronic structure of γ′ phase containing Mg in nickel-based superalloy is inves-tigated with SCF-X_n-SW method. Based on the model cluster presented for the strengtheningmechanism of Mg in γ′ phase, the energy levels, the density of states, the partial, wave localdensity of states and one-electron properties such as charge distribution, have been obtained.After substituting Mg for Al, the bonding states in low energy region increase, unoccupiedstates move towards more shallow potential well and energy gap becomes larger. All these canpredict that the proper Mg makes γ′ phase more stable. The charge transfer of Mg in γ′phase benefits Mg to be dissolved in γ′ phase.展开更多
The electronic structure and some one-electron properties of binary intermetallic compounds Fe3Al (the F1∶Al4 model cluster) and FeAl (the Fe7Al8 and Fe4Al4 model clusters) are investigated by the SCF-Xα-SW method. ...The electronic structure and some one-electron properties of binary intermetallic compounds Fe3Al (the F1∶Al4 model cluster) and FeAl (the Fe7Al8 and Fe4Al4 model clusters) are investigated by the SCF-Xα-SW method. The results show that the binding tendency between an Fe atom and the Fe3Al cluster is a little weaker than that between an Al atom and the Fe3Al cluster, which is in contrast to the case in FeAl. And charge is transferred from Al atoms to Fe atoms in both systems. Thus it is concluded that Al atoms contribute to the FIM image of Fe3Al whatever the imaging mechanism, selective evaporation or selective ionization is, which is in good agreement with our FIM experimental results. For FeAl, no definite experimental evidence regarding FIM imaging atom species is available so far. But our calculated result that Al atoms will be evaporated preferentially leads to the prediction that Fe atoms will be imaged in FIM micrographs.展开更多
文摘The SCF-Xα-SW molecular orbital calculations were carried out on the modelcompounds of binuclear and trinuclear gold(Ⅰ)using starting potential of Au atom and the Watson sphere.The energy level order of the frontier orbital of a binuclear gold model compound is in agreement with the experimental result.The calculated ionization potential of the binuclear model compound is consistent well with the photoelectron spectrum of Au (Me)(PMe_3).The metal-metal interactions are discussed.The calculated electronic absorption spectra of binuclear and trinuclear gold(Ⅰ)are basically in agreement with experimental results.
文摘Electronic structures of REBaCuO (RE=La, Pr, Nd, Sm, Gd, Dy, Ho and Er)systems were calculated by means of SCF-Xα -SW methods. Results show that there is an inner-orbitcoupling for these oxide superconductor systems. The inner-orbit coupling was resulted from theinteraction of two electronic orbits of RE 5p and O 2s, since they have similar energy state levelsand relatively larger orbital electronic clouds. Compared with experimental facts, it is also foundthat the overlap in space between the two orbits has a similar tendency to T_c and the number ofenrolling electrons has a close relation to J_c, therefore, the influence of inner-orbit coupling onsuperconductivity could not be overlooked.
文摘In the ZrO_2-based ceramic systems doped with different oxides (Y_(2)O_3, MgO and Al_(2)O_3), the behaviors of electronic and ionic conductivity have been investigated by the quantum chemical SCF-X_α-SW method. The results of the electronic energy spectra and local state density of atoms show that, for the ZrO_2 system doped with Al_2O_3, the energy gap near the Fermi energy level becomes smaller, which implies that the electronic conductivity increases. Since the binding energy between Al and O atoms is increased, the energy for oxygen vacancy migrating is enhanced and the ionic conductivity decreases. In the M_xO_y-doped ZrO_2 systems, due to the doping effect of Al_2O_3, MgO and Y_2O_3, the ionic conductivity increases successively, and the electronic conductivity decreases successively. The cal- culation results are in agreement with that of references and experience.
基金Project supported by the National Natural Science Foundation of China.
文摘The electronic structure of γ′ phase containing Mg in nickel-based superalloy is inves-tigated with SCF-X_n-SW method. Based on the model cluster presented for the strengtheningmechanism of Mg in γ′ phase, the energy levels, the density of states, the partial, wave localdensity of states and one-electron properties such as charge distribution, have been obtained.After substituting Mg for Al, the bonding states in low energy region increase, unoccupiedstates move towards more shallow potential well and energy gap becomes larger. All these canpredict that the proper Mg makes γ′ phase more stable. The charge transfer of Mg in γ′phase benefits Mg to be dissolved in γ′ phase.
基金Project supported by the National Natu ral Science Foundation of Chm(Grant No.59771018).
文摘The electronic structure and some one-electron properties of binary intermetallic compounds Fe3Al (the F1∶Al4 model cluster) and FeAl (the Fe7Al8 and Fe4Al4 model clusters) are investigated by the SCF-Xα-SW method. The results show that the binding tendency between an Fe atom and the Fe3Al cluster is a little weaker than that between an Al atom and the Fe3Al cluster, which is in contrast to the case in FeAl. And charge is transferred from Al atoms to Fe atoms in both systems. Thus it is concluded that Al atoms contribute to the FIM image of Fe3Al whatever the imaging mechanism, selective evaporation or selective ionization is, which is in good agreement with our FIM experimental results. For FeAl, no definite experimental evidence regarding FIM imaging atom species is available so far. But our calculated result that Al atoms will be evaporated preferentially leads to the prediction that Fe atoms will be imaged in FIM micrographs.
