Analyzers, electron energy differentiation

In 1979, the construction of an XPS system for the investigation of solids in gas atmospheres at pressures of up to 1 mbar was reported by Joyner and Roberts (1979a) this was later commercialized. One differential pumping stage around the high-pressure sample cell was used in combination with the commercial hemispherical electron energy analyzer ESCALAB of V.G. Scientific Ltd. Two "high-pressure" spectrometers of this type were supplied to the University of Wales (Cardiff, UK) and the Boreskov Institute of Catalysis (Novosibirsk, Russia). 

CMA cylindrical mirror analyzer DTA differential thermoanalysis EELS electron energy loss spectroscopy EDTA ethylenediaminetetraacetic acid... 

AES measurements were carried out in a differentiated mode with a 2 eV modulation amplitude, at either 3 or 0.5 keV of primary electron energy, and 0.5 pA sample current, using a Perkin Elmer (PHI) 10-155 cylindrical mirror analyzer (CMA). The analysis was conducted at a low beam current to minimize electron beam damage. Spectra were acquired using a digital data acquisition system, and smoothed one time using a 11 point averaging technique.. 

The XPS data were acquired on a Physical Electronics model 5400 XPS system using a Mg anode. For survey spectra, the pass energy was 44.75 eV with a step size of 0.5 eV. The time per step was 50 msec. High resolution spectra were acquired with a pass energy of 35.75 eV and step size of 0.1 eV, The time per step was 50 msec. Thermogravimetric data were obtained on a Perkin-Elmer, Diamond Thermogravimetric/ Differential Thermal Analyzer (TG/DTA) with Pyris software, version 7.0-0.0110. 

Sander applied DFT (B3LYP) theory to carbenic philicity, computing the electron affinities (EA) and ionization potentials (IP) of the carbenes." " The EA tracks the carbene s electrophilicity (its ability to accept electron density), whereas the IP represents the carbene s nucleophilicity (its ability to donate electron density). This approach parallels the differential orbital energy treatment. Both EA and IP can be calculated for any carbene, so Sander was able to analyze the reactivity of super electrophilic carbenes such as difluorovinylidene (9)" which is sufficiently electrophilic to insert into the C—H bond of methane. It even reacts with the H—H bond of dihydrogen at temperamres as low as 40 K, Scheme 7.2) ... 

Electron ionization sources produce constant ion beams of about 10 8 A with low initial energy spread. The ion current measured depends strongly on the ionization degree of the gas analyzed (type of atoms and molecules). Positive ions and electrons are formed by the interaction of electrons of sufficient energy with gas atoms or molecules. The ion current /+ is proportional to the pressure (p) of the gaseous sample, to the electron current /e, the length (/) of the collision chamber and the differential ionization (s) of elements as a function of the ionization energy ... 

One of the main goals of the crossed-beam experiment is to measure the internal energy AEvlh rol transferred to the molecule. In principle, this is possible in either of two ways. First, the scattered molecules could be detected and their product-state population analyzed. Infrared emission or absorption techniques may be considered, similar to those used in cell experiments.13 21 Although such studies would lead to the most detailed results (at least for polar molecules), under crossed-beam conditions they are impossible for intensity reasons, even if the possibility of measuring differential cross sections is renounced and the molecules in the scattering volume itself are detected. Detection via electronic molecular transitions may be invisaged. Unfortunately, the availability of tunable lasers limits this possibility to some exotic molecules such as alkali dimers. The future development of UV lasers could improve the situation. Hyper-Raman... 

The products obtained are determined by the energy spectrum for the compositions, mainly for the Ca/P mole ratio, and characterized by infrared spectroscopy with the Fourier transformation intra-red spectrophotometer (FTIR) of Type Nicolet 51 OP made by Nicolet Co., thermal analysis on a thermo- gravimetric/differential thermal analyzer (TG/DTA) of Type ZRY-2P, X-ray diffraction (XRD) analysis with the X-ray diffractometer of Type XD-5 made by Shimadzu Co., scanning electron microscopy (SEM), and transmission electron microscopy (TEM) with the transmission electron mirror microscope of Type JEM-100SX type made by JEOL Co. 

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