ESCA Measurements

The authors are grateful to the Robert A. Welch Foundation, the National Science Foundation, the Phillips Petroleum Foundation, and Haldor Topsoe A/S (Denmark) for financial support. We express our thanks to the Exxon Research and Engineering Co. for measuring the solid state NMR spectra and the Shell Development Company for the ESCA measurements. Finally, we acknowledge the participation of Dr. Zinfer R. Ismagilov in part of the cyclohexane studies. 

ESCA measurements were performed with an AEI ES200 spectrometer equipped with an A1 anode (1486.6 gV) and operated at 12 kV and 22 mA with a base pressure of 4 x 10 torr. The Nl 2p,2> 3p ... 

Auger electron spectrometry (AES), reported by Auger in 1923 [40], is also a valuable technique for analysing surfaces. The technique is somewhat similar to ESCA, measuring electrons emitted from a surface as a result of electron bombardment. In both cases, the sampling depth is ca. 20A. Coupling this technique with scanning electron microscopy (SEM) produced a tandem (AES-SEM) technique which has proved extremely productive. 

Figure 5. ESCA measurements (A) untreated OPP film (B) OPP film after surface grafting with AM (17)...

Information about the electronic structure of the 4,5-dimethoxy-o-quinodimethane adduct 46 in the solid state, prepared from 6,7-dimethoxy-3-isochromanone 42 (Rj = R4 = H R2 = R3 = OMe), comes from ESCA measurements [43]. In accord with the crystal structure analysis [43, 58], this cycloadduct, which contains the electron-rich dimethoxyphenyl moiety, shows an intermolecular donor-acceptor interaction, in particular, of the methoxy oxygen to the unit. 

All XPS or ESCA measurements were performed using a Perkin Elmer 5300 ESCA spectrometer equipped with a dual anode (Mg, Al) X-ray source, differentially pumped Ar+ sputter gun, and the variable angle measurement set-up for angle-resolved photoelectron spectroscopic measurements. The data collection and treatment, e.g. smoothing, curve-fitting, intensity measurements, were accomplished by a Perkin Elmer 7500 dedicated computer system using PHI software package. 

Grzybowska et al. (138) performed similar ESCA measurements on the three bisiputh molybdates, bismuth oxide, and molybdenum trioxide. The... 

Fig. 2. Binding energy (BE) of the Au(4f 1) level in compounds of different oxydation numbers (ON), from ESCA measurements (55, 89). (For compounds 3 and 4, see Section IV,5).

Values are mean values with the standard deviation shown in parentheses n=7 in each case, a ESCA measurements on silicon substrates, b Sessile drop measurements on glass slides, c Ellipsometry measurements on silicon substrates, d First receding contact angle. 

Lunsford and coworkers (26) have prepared a Ru(bpy)32 complex in zeolite Y and studied the quenching of oxygen and water. The emission bands of the ion-exchanged zeolite resemble those of aqueous solutions. Diffuse reflectance spectroscopy and ESCA measurements were also made in the characterization of these samples. 

NR055X and 703 polyamic resin material were separately coated onto cleaned silicon substrates so as to produce a resin layer v2y thick. Each sample t e was subsequently heated on a hot plate for 10 minutes at 85 C to remove solvent from the films to produce the condensed phase amic acid. Specimens were sequentially step cured as follows 10 minutes at 200°C 30 minutes at 300 0 on a hot plate having a lid in a N flow and 30 minutes at 400 C in a closed tube furnace in a flowing stream of N. (in separate experiments, a flowing stream of forming gas, i.e., 80% N2-20% H2> was used for the 300°C and 400°C cures). ESCA measurements were made after each curing step in order to evaluate differences caused by increasing the temperature of cure. 

ESCA measurements were carried out on a Kratos XSAM-800 instrument with a Mg anode (200 watts) at a vacuum of 10 torr. TEM analysis was done on a Phillips IL 520T STEM at 100 kV in the TEM mode. 

From these results we can conclude that the point charge model is self-consistent with respect to the derived charges. We will see below, however, that these charges are much smaller than those obtained by other experimental techniques. In addition, there are some discrepancies between the derived values of k and those obtained from other methods. In particular, the k s derived by us and by others from ESCA measurements are consistently higher than those calculated for free atoms either using the equivalent cores approximation or by other theoretical methods. " The use of... 

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