摘要:

Calcite is a common component of soil and a natural mineral sometimes found in the form of large high quality single crystals. The interactions of calcite with ions in groundwater affect their transport in the environment. Consequently, understanding the surface chemistry of calcite is important for environmental remediation research. The measurements reported here were conducted to provide high quality valence band and core level spectra of the clean calcite surface and for comparison with data collected on an older instrument with lower spatial and energy resolution. A single crystal was broken in vacuum to expose the (101¯4) plane of rhombohedral calcite (CaCO3) for XPS analysis. Survey and multiplex spectra were collected under standard operating conditions with a Perkin Elmer Physical-Electronics 5600 spectrometer using monochromatic AlKαx rays. An electron flood gun was used to control surface charging during the measurements.

ISSN:1055-5269    

DOI:10.1116/1.1247719

出版商:American Vacuum Society    

年代:1993

数据来源: AIP

摘要:

Polytetrafluorethylene (PTFE) is a technologically important material employed for broad applications due to its exceptional properties for lubrication, insulation, and chemical inertness. With regard to surface analysis, PTFE has been found to provide a ready standard source for the x-ray photoelectron F 1sline in a polymeric matrix. A previous submission [M. Ackeret, Surf. Sci. Spectra1, 100 (1992)] examined the uniformity of the atomic composition over the surface layers by angle dependent XPS analysis of the C 1sand F 1slines. In this submission we wish to present a compilation of the photoelectron, Auger, and valence band transitions excited by monochromatic Al x-ray radiation.

ISSN:1055-5269    

DOI:10.1116/1.1247715

出版商:American Vacuum Society    

年代:1993

数据来源: AIP

摘要:

XPS measurements of the core levels, including energy losses, and the valence band of a MgO(100) crystal are presented.

ISSN:1055-5269    

DOI:10.1116/1.1247718

出版商:American Vacuum Society    

年代:1993

数据来源: AIP

摘要:

High quality sodium chlorite has been analyzed as part of a series of chlorine oxyacid salts, chlorite to perchlorate. The spectra include survey and high resolution scans over the major photopeaks, the sodium Auger transitions and the valence band of the compound. Spectra for this compound were collected with the magnesium x-ray source. Several literature references are provided as additional sources of XPS data and description of the chemistry of chlorine oxyacid anions.

ISSN:1055-5269    

DOI:10.1116/1.1247720

出版商:American Vacuum Society    

年代:1993

数据来源: AIP

摘要:

High quality sodium chlorate has been analyzed as part of a series of chlorine oxyacid salts, chlorite to perchlorate. The spectra include survey and high resolution scans over the major photopeaks, the sodium Auger transitions and the valence band of the compound. Spectra for this compound were collected with the magnesium x-ray source. Several literature references are provided as additional sources of XPS data and description of the chemistry of chlorine oxyacid anions.

ISSN:1055-5269    

DOI:10.1116/1.1247721

出版商:American Vacuum Society    

年代:1993

数据来源: AIP

摘要:

X-ray photoemission spectra of the core and valence band levels for an amorphous Al90Fe7Ce3ribbon are presented. Survey scan and high resolution multiplexes of the C 1s, O 1s, F 1s, Al 2p, Al 2s, Fe 2p, and Ce 3dphotoelectron lines and the valence band region were collected on a Perkin-Elmer/Physical Electronics model # 5400 photoelectron spectrometer using monochromatized Al x rays. Angle resolved spectra of the O 1s, Al 2p, and Al 2sphotoelectron lines for emission angles of 5°, 15°, 25°, 35°, 45°, 55°, 60°, 65°, 70°, 75°, 78°, and 80° relative to sample normal were also collected to aid in identifying the chemistry of the native oxide. The material, 25μm thick amorphous ribbon, was prepared by rapid solidification of the metallic components from the liquid phase using the melt-spinning method. The material is of technological importance due to its extremely high strength, low density, and anticipated high corrosion resistance. Analysis of XPS data reveals the following conclusions: (i) the chemistry of the native oxide is similar to that of an aluminum oxyhydroxide chemistry namely, AlOx(OH)y, (ii) the oxygen 2sline consists of low (~531.2 eV) and high (~532.4 eV) binding energy peaks corresponding to ionic O and OH chemistries in AlOx(OH)y, respectively, with the ratio of the mole fraction of OH to that of O decreasing with decrease in electron emission angle, (iii) both the aluminum 2pand 2slines consist of low and high binding energy peaks corresponding to Al in AlOx(OH)yand Al in Al90Fe7Ce3, respectively, (iv) both Fe and Ce are present in metallic forms as in Al90Fe7Ce3with no indication of any segregation of oxidized species into the native oxide region, (v) F is present in small quantities as a surface impurity, and (vi) the presence of a native oxide coating of AlOx(OH)ymay enhance the corrosion resistance of such a class of amorphous alloys.

ISSN:1055-5269    

DOI:10.1116/1.1247722

出版商:American Vacuum Society    

年代:1993

数据来源: AIP

摘要:

Tin and various tin compounds have wide utility in coatings, electronics, and catalysts, as well as having numerous biological applications. Distinguishing between different tin compounds on surfaces is an important aspect of research in many of these disciplines. In this work, x-ray photoelectron spectroscopy has been used to obtain comparison spectra of a SnO powder. The SnO powder was generated by grinding ~150μm granules of SnO in a mortar and pestle. Grinding is necessary because surface oxidation of the SnO granules occurs producing a SnO2shell. It has been shown that differences in the valence band spectra provide the most direct method of distinguishing between SnO2and SnO [see J-M. Themlin, M. Chtaib, L. Henrard, P. Lambin, J. Darville, and J-M. Gilles, Phys. Rev. B46, 2460 (1992); P. M. A. Sherwood,ibid.41, 10151 (1990); and C. L. Lau and G. K. Wertheim, J. Vac. Sci. Technol.15, 622 (1978)]. The separation between the Sn 4dcore level line and the most intense Sn valence peak is also characteristic of Sn oxides [see J-M. Themlin, M. Chtaib, L. Henrard, P. Lambin, J. Darville, and J-M. Gilles, Phys. Rev. B46, 2460 (1992) and P. M. A. Sherwood,ibid.41, 10151 (1990)]. In the present study, identification of the powder as SnO after grinding was verified by comparison of the measured XPS valence band spectrum with published spectra [J-M. Themlin, M. Chtaib, L. Henrard, P. Lambin, J. Darville, and J-M. Gilles, Phys. Rev. B46, 2460 (1992) and C. L. Lau and G. K. Wertheim, J. Vac. Sci. Technol.15, 622 (1978)] and by the XPS Sn:O atomic ratio. The valence band–Sn 4dseparation is also consistent with that determined for SnO [see J-M. Themlin, M. Chtaib, L. Henrard, P. Lambin, J. Darville, and J-M. Gilles, Phys. Rev. B46, 2460 (1992)]. Core level, valence band and x-ray excited Auger spectra for the SnO powder are presented. Data were obtained with a Perkin-Elmer Physical Electronics model 5600 photoelectron spectrometer using monochromatic radiation.

ISSN:1055-5269    

DOI:10.1116/1.1247723

出版商:American Vacuum Society    

年代:1993

数据来源: AIP

摘要:

Tin and various tin compounds have wide utility in coatings, electronics, and catalysts, as well as having numerous biological applications. Distinguishing between different tin compounds on surfaces is an important aspect of research in many of these disciplines. In this work, x-ray photoelectron spectroscopy has been used to obtain comparison spectra of a high purity SnO2powder. Due to rather small core level chemical shifts, it has been shown that differences in the valence band spectra provide the most direct method of distinguishing between SnO2and SnO using XPS [see J-M. Themlin, M. Chtaib, L. Henrard, P. Lambin, J. Darville, and J-M. Gilles, Phys. Rev. B46, 2460 (1992); P. M. A. Sherwood,ibid.41, 10151 (1990); and C. L. Lau and G. K. Wertheim, J. Vac. Sci. Technol.15, 622 (1978)]. The separation between the Sn 4dcore level line and the most intense Sn valence band peak is also characteristic of Sn oxides [see J-M. Themlin, M. Chtaib, L. Henrard, P. Lambin, J. Darville, and J-M. Gilles, Phys. Rev. B46, 2460 (1992) and P. M. A. Sherwood,ibid.41, 10151 (1990)]. The valence band spectrum and the valence band–Sn 4dseparation reported in this work are consistent with literature data [see J-M. Themlin, M. Chtaib, L. Henrard, P. Lambin, J. Darville, and J-M. Gilles, Phys., Rev. B46, 2460 (1992); P. M. Sherwood,ibid.41, 10151 (1990); and C. L. Lau and G. K. Wertheim, J. Vac. Sci. Technol.15, 622 (1978)]. Auger parameter data may also prove useful for distinguishing between various tin compounds on surfaces. Thus, in addition to core level spectra, valence band and x-ray excited Auger spectra for SnO2are presented. Data were obtained with a Perkin-Elmer Physical Electronics model 5600 photoelectron spectrometer using monochromatic radiation.

ISSN:1055-5269    

DOI:10.1116/1.1247724

出版商:American Vacuum Society    

年代:1993

数据来源: AIP

摘要:

High energy resolution spectra of high purity Cu foil that was scraped in situ are presented. The experimental width (16%–84% measurement) of the Fermi level of nickel obtained under identical experimental conditions was 0.32 ± 0.02 eV. The binding energy scale calibration is based on the position of the Au 4f7/2line which is taken to be 83.98 eV [see M. T. Anthony and M. P. Seah, Surf. Interface Anal.6, 95 (1984)]. The Auger spectra are presented primarily to provide information on the detailed structure of the line at high energy resolution and accurate measurements of the relative separations between the transitions contained within the line. Since the kinetic energy of a photoelectron depends upon the photon energy and the kinetic energy of an Auger electron does not, the position of the Auger electron on the binding energy scale is a function of the photon energy. For nonmonochromatic x-ray excitation, the positions of the photoelectron lines and Auger lines are fixed relative to one another because the natural x-ray line has a defined centroid. However, for monochromatic AlKαradiation, the exact photon energy can deviate from the centroid energy by as much as 0.3 eV. Thus, there can be systematic deviations in the binding energies of the Auger lines as recorded with instruments using monochromatic radiation as compared to those using nonmonochromatic x-ray sources. Comparison of theL3M4,5M4,5line position with other published work [see M. P. Seah, G. C. Smith, and M. T. Anthony, Surf. Interface. Anal.15, 293 (1990)] suggests that our photon energy is 1486.73 eV, and that all of the Auger line positions recorded in the table are systematically displaced by 0.15 eV.

ISSN:1055-5269    

DOI:10.1116/1.1247725

出版商:American Vacuum Society    

年代:1993

数据来源: AIP

摘要:

X-ray photoemission spectra from Si which has been chemically etched in HF (hydrofluoric acid) are presented. The data include measurements of the valence band region, Si 2pregion, Si 2sregion, and O 1sregion. These data are useful for comparison to the oxidized Si.

ISSN:1055-5269    

DOI:10.1116/1.1247726

出版商:American Vacuum Society    

年代:1993

数据来源: AIP