Binding energy referencing

Binding energy referenced to Au(4f 7/2) level at 83.8 eV for thin layer of gold evaporated onto sample. 

The PHI Model 548 ESCA/ AES spectrometer (Physical Electronics Inc., Eden Prairie, MN) previously described (10,13) has been modified by the replacement of the original x-ray source with a PHI Model 1548 dual anode, 300W x-ray source. All binding energies are referenced to the Au 4f peak at 83.8 eV. 

X-ray Photoelectron Spectroscopy analysis of the samples was performed with a Surface Science Instruments spectrometer (SSI 100) with a resolution (FWHM Au 4f7/2) of 1.0 eV. The X-ray beam was a monochromatised AlKa radiation (1486.6 eV). A charge neutraliser (flood gun) was adjusted at an energy of 6 eV. As the Cls spectra of these compounds were very complex, the binding energies were referenced to the binding energy of Ols, considered experimentally to be at 531.8 eV [8). 

The XPS spectra of the freshly sulfided Co-Mo/NaY catalysts were measured on an XPS-7000 photoelectron spectrometer (Rigaku, A1 anode 1486.6 eV). The sample mounted on a holder was transferred from a glove bag into a pretreatment chamber attached to the spectrometer as possible as carefully not to be contacted with air. The binding energies (BE) were referenced to the Si2p band at 103.0 eV for the NaY zeolite, which had teen determined by the Cls reference level at 285.0 eV due to adventitious carbon. 

The 5950A ESCA spectrometer is interfaced to a desktop computer for data collection and analysis. Six hundred watt monochromatic A1 Ka X-rays are used to excite the photoelectrons and an electron gun set at 2 eV and 0.3 mAmp is used to reduce sample charging. Peak areas are numerically integrated and then divided by the theoretical photoionization cross-sections (11) to obtain relative atomic compositions. For the supported catalyst samples, all binding energies (BE) are referenced to the A1 2p peak at 75.0 eV, the Si 2p peak at 103.0 eV, or the Ti 2p3/2 peak at 458.5 eV. 

Figure 10.6 (A) Desorption temperature of a 1 ML Pd film from different metal substrates. (B) Change in Pd(3d5/2) binding energy as a function of the metal substrate. The changes are referenced to the Pd(3d5/2) binding energy of Pd(100). (Reprinted from Rodriguez, J.A. and Goodman, D.W., Science, 257, 897-903, 1992. Copyright 1992. With permission from AAAS.)...

X-Ray Photoelectron Spectroscopy. Spectra were obtained using a Leybold-Heraeus LHS-10 Spectrometer using a Mg Ka anode. All binding energies for the obtained spectra were referenced to the hydrocarbon alkane line at 285.0 eV. 

Binding energies (B.E.) in eV ( 0.1 eV) for catalysts before and after catalytic formation of carbon nanotubes charge shifts removed, then B.E. s referenced to C (Is) - 284.6 eV ... 

Figure 3. XPS spectra of a silicon sample containing ca. 30 nm thick oxide. A strip of gold metal is tied for referencing under different voltage stress. The inset displays the measured binding energy difference between the Si2p of the oxide layer (Si4+), and the Au4f of the gold metal. Zero Charge Point (ZCP) is obtained at ca. +1V stress.

However, equation (3) still contains two unknowns the work function of the metal and the work function of the gold deposit. A multilaboratory study has shown that neither carbon nor gold provide a suitable internal standard for catalyst supports (34). Alternatively, the binding energy scale has been referenced to a core level of the support metal cation, for example, the Si 2p peak of silica. This is no improvement. The work function of a high surface area, amorphous catalyst support has never been measured. 

The results of XPS studies of metal-support interactions (9.10.18.20-25) can be reexamined in light of the analysis presented above. All of the binding energy measurements made in these studies were referenced to an internal standard. For large metal particles, the core level shifts may be explained by any combination of the following ... 

Chemical analysis of the superficial regions of the samples was performed by X-ray photoelectron spectroscopy (XPS) with a Perkin-Elmer Phi 5300 ESCA, employing Mg Ka x-rays. Binding energies are referenced to the gold fy/2 transition at 83.8 eV (gold was sputtered onto a small spot of the sample prior to analysis). 

---