Big Chemical Encyclopedia

Chemical substances, components, reactions, process design ...

Articles Figures Tables About

Ultra high pressure experiments

Figure 8. LogD, vs. LogDa " . Triangles are from [108] and the lines are regressions to the data from [108]. Other high pressure and ultra-high pressure experiments are labeled (solid symbols, see text). Open squares are the data of [73] that were averaged to get the value (solid square -K16-24A) reported by [73]. Although there is much scatter, there is a suggestion that the parameterizations of Dree that were useful for pyroxenes may also be useful for garnet and majorite. Figure 8. LogD, vs. LogDa " . Triangles are from [108] and the lines are regressions to the data from [108]. Other high pressure and ultra-high pressure experiments are labeled (solid symbols, see text). Open squares are the data of [73] that were averaged to get the value (solid square -K16-24A) reported by [73]. Although there is much scatter, there is a suggestion that the parameterizations of Dree that were useful for pyroxenes may also be useful for garnet and majorite.
The success of piezospectroscopy experiments in the above materials strongly suggests the application to other indirect gap binary semiconductors such as AlSb, AlAs, etc. as well as indirect alloy materials such as GaAlAs, GaAsP, etc. In addition, information about intervalley EP and HP scattering matrix elements could also be obtained from ultra high pressure experiments (such as in a diamond anvil cell) where a direct gap material, such as GaAs, can be made indirect. [Pg.490]

Extremely accurate determination of the high- and ultra-high-pressure equation of state of bulk Al, including prediction of how close the most recent diamond anvil cell experiment came to achieving the fee— hcp phase transition [23,92]... [Pg.208]

The assignment of the well depth for H20 + H2O was speculative and based on the failure to observe H20 H2O in chemical ionization experiments. This value may well be incorrect since the ion mje = 36 (assigned the structure H30 OH) has been observed both in a flowing afterglow and in an ultra-high-pressure mass spectrometer at 300°K (see Chapter 8, Section 2.4). [Pg.242]

Vibrational spectroscopic studies of heterogeneously catalyzed reactions refer to experiments with low area metals in ultra high vacuum (UHV) as well as experiments with high area, supported metal oxides over wide ranges of pressure, temperature and composition [1]. There is clearly a need for this experimental diversity. UHV studies lead to a better understanding of the fundamental structure and chemistry of the surface-adsorbate system. Supported metals and metal oxides are utilized in a variety of reactions. Their study leads to a better understanding of the chemistry, kinetics and mechanisms in the reaction. Unfortunately, the most widely used technique for determining adsorbate molecular structure in UHV,... [Pg.435]

Low pressure studies Adsorption of CO. The experiments were performed in an ultra-high vacuum system described previously (1). The data obtained on palladium particles with a size smaller than 2 nm or larger than 3 nm will be discussed in turn. [Pg.432]

The X-ray photoelectron spectroscopy (XPS) experiments were performed in an ultra-high vacuum (UHV) chamber coupled to an atmospheric pressure reaction cell. All XPS results were obtained from samples treated in situ in the reaction cell and transferred into UHV without exposure to air. Detailed sample mounting procedures and instrument details are described elsewhere.16 Ar+ bombardment was done with 3 KeV Ar+ ions at a current density of 0.8 pA/cm2 for 1 h in an attempt to remove the carbon overlayer and expose the underlying carbide phase. [Pg.548]

Of course, everything except the electronics and data system associated with the SIMS experiment must be In a vacuum system, with the experimental results desired dictating the degree of vacuum required. This can range from ultra-high vacuum to pressures achievable with a simple diffusion pump. [Pg.99]

Surface science experiments are, for the most part, conducted under ultra-high vacuum conditions (UHV), generally with base pressures in the range of 10 8—10 11 Torr. This is done in order to maintain... [Pg.111]

Nearly all the experiments described were performed in an ultra high vacuum chamber at pressures of about 10 10 torr. The specific equipment and experimental procedures used have been described elsewhere (7-9). Experimental protocol for the thermal desorption experiments and for the chemical displacement reactions is presented below. All these experiments were repeated with a control, blank experiment with a metal crystal that had the front and exposed face covered with gold the sides and back of the crystal were exposed (8,9). These blank experiments were performed to ensure that all thermal desorption and chemical displacement experiments monitored only the surface chemistry of the front exposed face of the metal crystal under study. [Pg.275]

The experiments were performed in two different ultra high vacuum (UHV) chambers using two different Pt(lll) single crystals. The X-ray photoelectron spectra were obtained in a chamber with a base pressure of lxlO" Torr. The system has been described in detail elsewhere. In brief, the UHV chamber is equipped with low energy electron diffraction (LEED), an X-ray photoelectron spectrometer (XPS), a quadrupole mass spectrometer (QMS) for temperature programmed desorption (TPD), and a Fourier transform infrared spectrometer (FTIR) for reflection absorption infrared spectroscopy (RAIRS). All RAIRS and TPD experiments were performed in a second chamber with a base pressure of 2 X 10 ° Torr. The system has been described in detail elsewhere. In brief, the UHV chamber is equipped for LEED, Auger electron spectroscopy (AES) and TPD experiments with a QMS. The chamber is coupled to a commercial FTIR spectrometer, a Bruker IFS 66v/S. To achieve maximum sensitivity, an... [Pg.117]

Experiments are performed in an ultra-high vacuum (UHV) chamber with a base pressure of better than 5 x 10 T. A pulsed molecular beam is used to dose gases on a thin film single-crystal surface of 200-nm thickness. Each pulse, which... [Pg.176]


See other pages where Ultra high pressure experiments is mentioned: [Pg.168]    [Pg.279]    [Pg.175]    [Pg.152]    [Pg.123]    [Pg.797]    [Pg.95]    [Pg.302]    [Pg.311]    [Pg.166]    [Pg.521]    [Pg.43]    [Pg.477]    [Pg.100]    [Pg.118]    [Pg.45]    [Pg.538]    [Pg.475]    [Pg.155]    [Pg.167]    [Pg.34]    [Pg.137]    [Pg.153]    [Pg.154]    [Pg.391]    [Pg.393]    [Pg.252]    [Pg.81]    [Pg.605]    [Pg.331]    [Pg.372]    [Pg.187]    [Pg.353]    [Pg.245]    [Pg.112]    [Pg.290]    [Pg.467]    [Pg.187]   
See also in sourсe #XX -- [ Pg.490 ]




SEARCH



High experiments

High pressure experiments

Pressure experiments

Ultra high-pressure

Ultra-high

© 2024 chempedia.info