Torres

A schematic diagram of the apparatus is shown in Figure 3.2. The molecules are introduced under a partial vacuum of 10 torr into a buffer chamber that communicates via molecular slipstream with the source itself at 10 to 10 torr in order to ensure a constant concentration in the source at all times during the analysis. 

The variation of Bq causes all ions to pass sequentially in front of the exit slit behind which is positioned the photomultiplier detector. The pressure in the apparatus is held at 10 torr in order to achieve mean free paths of ions sufficiently high that all ions emitted from the source are collected. 

Fig. XVI-5. Resonance Raman spectra of MDMA adsorbed on ZnO (a) in the presence of 100 torr of NH3 (b) after evacuation of the NH3 from the cell. [Reprinted with permission from J. F. Brazdil and E. B, Yeager, J. Phys. Chem., 85, 1005 (1981) (Ref. 79). Copyright 1981, American Chemical Society.]...

MBE is accomplished under UHV conditions with pressures of the order of Torr. By using such low... 

Torr, with the (100) face of MgO parallel to the Mo(lOO) surface. Figure A3.10.13 shows a ball model... 

Figure A3.10.20 Arrhenius plot of ethane hydrogenolysis aetivity for Ni(lOO) and Ni(l 11) at 100 Torr and H2/C2Hg = 100. Also ineluded is the hydrogenolysis aetivity on supported Ni eatalysts at 175 Torr and H2/C2H6 = 6.6 [43].

Torr) over tliree single-erystal Ni surfaees at 450 K. The rate of methane deeomposition is obviously dependent upon tire surfaee stnieture with tlie deeomposition rate inereasmg in the order (111) < (100) < (110). It ean be seen that, initially, the rates of methane deeomposition are... 

Figure A3.10.21 Methane deeomposition kineties on low-index Ni single erystals at 450 K and 1.00 Torr methane [43],...

The molecule decomposes by elimination of CF, which should occur with equal probabilities from each ring when energy is randomized. However, at pressures in excess of 100 Torr there is a measurable increase in the fraction of decomposition in the ring that was initially excited. From an analysis of the relative product yield versus pressure, it was deduced that energy flows between the two cyclopropyl rings with a rate of only 3x10 s In a related set of experiments Rabinovitch et al [116] studied the series of chemically activated fliioroalkyl cyclopropanes ... 

A sehematie diagram of a SIFT apparatus is shown in figure Bl.7.12. The instrument eonsists of five basie regions, the ion soiiree, initial quadnipole mass filter, flow tube, seeond mass filter and finally the deteetor. The heart of the instrument is the flow tube, whieh is a steel tube approximately 1 m long and 10 em in diameter. The pressure in the flow tube is kept of the order of 0.5 Torr, resulting in earrier gas flow rates of... 

Figure Bl.22.1. Reflection-absorption IR spectra (RAIRS) from palladium flat surfaces in the presence of a 1 X 10 Torr 1 1 NO CO mixture at 200 K. Data are shown here for tluee different surfaces, namely, for Pd (100) (bottom) and Pd(l 11) (middle) single crystals and for palladium particles (about 500 A m diameter) deposited on a 100 A diick Si02 film grown on top of a Mo(l 10) single crystal. These experiments illustrate how RAIRS titration experiments can be used for the identification of specific surface sites in supported catalysts. On Pd(lOO) CO and NO each adsorbs on twofold sites, as indicated by their stretching bands at about 1970 and 1670 cm, respectively. On Pd(l 11), on the other hand, the main IR peaks are seen around 1745 for NO (on-top adsorption) and about 1915 for CO (tlueefold coordination). Using those two spectra as references, the data from the supported Pd system can be analysed to obtain estimates of the relative fractions of (100) and (111) planes exposed in the metal particles [26].

Zaera F, Fischer D A, Shen S and Gland J L 1998 Fluorescence yield near-edge X-ray absorption spectroscopy under atmospheric conditions CO and FI2 coadsorption on Ni(IOO) at pressures between 10 and 0.1 Torr Surf. Sc/. 194 205-16... 

In practical applications, gas-surface etching reactions are carried out in plasma reactors over the approximate pressure range 10 -1 Torr, and deposition reactions are carried out by molecular beam epitaxy (MBE) in ultrahigh vacuum (UHV below 10 Torr) or by chemical vapour deposition (CVD) in the approximate range 10 -10 Torr. These applied processes can be quite complex, and key individual reaction rate constants are needed as input for modelling and simulation studies—and ultimately for optimization—of the overall processes. 

Figure C2.18.5. Si(2p) spectmm of Si(l 11) reacted with 5 x 10 Torr of XeF2, using photon energy of 130 eV. The top panel shows the raw data and the fitted background. The bottom panel shows the spectmm after background has been subtracted and fitted into five components bulk Si and the four fluorosilyl peaks. The solid curve is the sum of the individual dashed component curves. Reproduced from [40].

Figure C2.18.7. The integrated absorbance of tire Si-Cl stretching vibration at 625 cm and tire SiO-H stretching vibration at 3740 cm as a function of time during tire (A) SiCl and (B) H2O half-reactions at 600 K and 10 Torr. Reproduced from [95].

Torr (mm of mercury) Torr Volume flow rate ... 

The work function (p is the energy necessary to just remove an electron from the metal surface in thermoelectric or photoelectric emission. Values are dependent upon the experimental technique (vacua of 10 or torr, clean surfaces, and surface conditions including the crystal face identification). 

The working temperature, 77 K, is well below the triple point of krypton, 116 K, but if the solid is taken as the reference state the isotherm shows an unusually sharp upward turn at the high-pressure end. The usual practice, following Beebe, is therefore to take p° as the saturation vapour pressure of the supereooled liquid (p° = 2-49 Torr at 77-35 K and 27-5 Torr at 90-2 K). 

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