Semiquantitative Analysis of Solid Surfaces by X-Ray Photoelectron Spectroscopy(Chemistry)

An application of the equation (1) to the semiquantitative analysis of solid surface by X-ray photoelectron spectroscopy were performed. chemical formula……(1) Where n is the concentration of the element in terms of atoms per unit volume, N is the intensity of ejected photoelectrons, σ is the photoionization cross section, λ is the mean free path for photoelectron in the sample, and S is the spectrometer (sensitivity) factor. The atomic ratios of oxygen to metal element in some oxides could be obtained with satisfactory results by the application of theoretical values of photoionization cross sections and mean free paths. In this case the summation of main and satellite peak intensities were employed for the calculation. Furthermore the atomic ratio of metallic state elements, oxide state ones and oxygen on copper-nickel alloy surface and surface enrichment of nitrogen and sulfur on iron surface were discussed

The Spectroscopic Observation of the Selective Volatilization of Metal Solid Samples in a Nitrogen Plasma Flame

Some metal solid samples were burned in a nitrogen plasma flame, and the spectrum intensity-time curves were spectrographically observed. The curves indicated that the fractional distillation of alloying elements was caused by the reactions of the solid alloy sample and nitrogen gas. The fractional distillation was explained in terms of the difference in the stabilities of the metal nitrides. The distribution of the emission species and the temperature of the flame suggested that there were few chemical reactions in the flame or that the chemical reactions in the flame had little effect on the spectrum intensities. In an appendix, the method of line-pair selections for obtaining the correct temperature is considered

Application Examples of Semiquantitative X-Ray Photoelectron Spectroscopic Analysis

Semiquantitative analytical applciation of X-ray photoelectron spectroscopy has been investigated. The estimation of a layer composition under surface as well as a surface layer composition is described for nickel-copper alloys. The possible utilities of the X-ray photoelectron technique to the study of precipitation phenomena are also explored, which include the coprecipitation of lead sulfate with barium sulfate and the post precipitation of zinc sulfide on the surface of copper sulfide

Photoelectron Spectral Intensities of Some First Transition Series Elements in Metal Cyanides Containing Inequivalent Atoms(Chemistry)

Photoelectron spectral intensities of some first transition series elements were studied for metal cyanides containing inequivalent atoms. The spectra of low-spin ions coordinated via carbon to the cyanide ion, and of high-spin ions coordinated through nitrogen were separately obtained from manganese, iron, and cobalt cyanides. Metal 2p spectra obtained as sums of the appropriate spectra of low- and high-spin ions were nearly coincident with the spectra of the compounds containing inequivalent atoms. These results show that the intensity of the 2p electron for each atom must include the main peak and perhaps multiplet splitting effects, shake-up effects, and the inelastic scattering tail, and verify the non-interaction nature of the inequivalent atoms in these compounds

On the Surface Chemical Reactions of Metal and Oxide XPS Samples at 300-400°at a High Vacuum Produced by Oil Diffusion Pumps(Chemistry)

Metal and oxide surface reactions formed by heating in the spectrometer at 300-400° at a vacuum of ca. 10^ Torr (oil diffusion pumps) were studied. As a result of spectral observations before and after heating, the metals studied were classified into five groups. In the first group, oxide films on the metal surface are easily evaporated because of the high vapour pressure of oxide ; in the second, the oxide films are easily reduced in the spectrometer ; in the thrid, the oxide film formed on the metal is reduced but the bulk oxide is not easily reduced ; in the fourth, very stable oxide films are formed and the bulk oxide is also stable ; and finally in the fifth, the oxide film formed on the metal is apparently reduced, yet the bulk oxide is very stable

X-Ray Photoelectron Spectroscopy of Manganese-Oxygen Systems(Chemistry)

The Mn 2p, Mn 3s, Mn 3p, and O 1s spectra of various manganese oxides were studied at room temperature, 200℃ and 400℃. The binding energies of manganese core electrons for MnO did not change after the sample had been exposed to air. The spectra of α-Mn_2O_3 and β-MnO_2 heated to 400℃ were identical to that of Mn_3O_4, which is the most thermodynamically stable species. Neither the two oxidation states of Mn in Mn_3O_4 nor the Mn site differences in γ-Mn_2O_3 were distinguishable by XPS. Satellite peaks were observed for manganese core electron peaks, which were sensitive to the surface conditions. The shake-up energy in the manganese oxides decreased markedly between the d^4 and d^5 materials

Coupling of codoped In and N impurities in ZnS:Ag: Experiment and theory

A vapor-phase-grown epitaxial ZnS:Ag layer simultaneously codoped with In and N on GaAs substrate exhibited a 436-nm light emission and p-type conduction with a low resistivity. X-ray photoemission spectroscopy revealed that the In 3d5/2 electron binding energy of the codoped ZnS:In,N layer was smaller by 0.5 eV than that of the ZnS:In independently doped layer, although the 2p3/2 electron binding energies of Zn and S of the codoped layer agreed well with those of the independently doped layer, respectively. The reduction of binding energy was ascribed to an increase in the electronic relaxation energy for core-hole states in photoemission and reflects a large charge transfer between the In and N atoms at the first neighbor sites through covalent sp3 bonding orbitals. An increase of the spectral intensity at around 4 eV relative to the valence band maximum observed for the codoped layer corresponds to a new state at –3.67 eV from the valence band maximum due to a strong coupling between the In 5s and N 2p orbitals at the first neighbor sites, derived from a first-principle band structure calculation for ZnS:(In,2N)

Photoelectron energy-loss functions of SrTiO3, BaTiO3, and TiO2: Theory and experiment

We compare experimental O 1s electron energy-loss structures below 30 eV of single crystalline SrTiO3 ,BaTiO3, and TiO2 with their theoretical electron energy-loss functions. The photoelectron energy-loss structuresof in situ fractured surface in ultrahigh vacuum can be approximated by a sum of four components forSrTiO3 and BaTiO3, and of three components for TiO2. Electronic structures were calculated from first principlesusing the full-potential linearized augmented plane-wave method in the local-density approximation. Themomentum matrix elements between Bloch functions were evaluated to determine the electron energy-lossfunctions. The theoretical electron energy-loss functions agree well with experimental spectra except a structureat around 20 eV of SrTiO3 and that at around 18 eV of BaTiO3. The difference of high binding energypeaks is explained from the positions of semicore states

Electronic structure and electrical properties of amorphous OsO2

The valence-band spectrum of an amorphous OsO2 film deposited by glow discharge of OsO4 vapor can be predicted well with calculated electronic band structure of crystalline OsO2 from first principles using the liner-muffin-tin-orbital method with the local-density approximation. Resistivity of the amorphous OsO2 was less than 631023 V cm at 80 K, and it was almost temperature independent, but the temperature coefficient of resistivity was negative. The Hall coefficient of the amorphous OsO2 increased with temperature, and was saturated at around 220 K. Temperature dependence of the Hall mobility was proportional to T3/2, and it implies that the scattering of charged carriers by ionized atoms is dominant below 220 K

Large frequency dependence of lowered maximum dielectric constant temperature of LiTaO3 nanocrystals dispersed in mesoporous silicate

A large frequency dependence of the maximum dielectric constant temperature was observed for LiTaO3 nanocrystals (the diameter 20 Å) dispersed in mesoporous silicate. At the applied field frequency of 100 kHz, the maximum temperatures in the real and imaginary parts were 365 and 345 °C, respectively. The maximum temperature in the real part is apparently lower than the paraelectric–ferroelectric transition temperature (645 °C) of bulk LiTaO3. The maximum temperature in the imaginary part rose from 285 to 420 °C with increasing frequency from 10 to 1000 kHz. Since the bulk LiTaO3 shows no relaxor behavior, such superparaelectric behavior is obviously a consequence of nanominiaturization of LiTaO3 crystal and insignificant cooperative interactions between the nanoparticles