Monochromator secondary

In using a similar approach, Thiine et al. [29] applied static SIMS to show that Cr/SiC>2 model catalysts which are active for ethylene polymerization contain only monochromates. Secondary ions with more than one Cr ion in the cluster, such as Cr2C>4 and Cr203, disappeared from the spectra after the catalysts had been calcined only CrSiOx ions remained. Aubriet et al. [30] studied the anchoring of chromium acetyl acetonate, Cr(acac)3 to a planar SiO2/Si(100) model support with static SIMS. Chromium polymerization catalysts are discussed further in Chapter 9. 

Figure 12.11 shows the pyrograms of vinyl paints from two monochromes by the Italian artist Piero Manzoni. The two paints are clearly different in composition acetic acid (peak 1) and benzene (peak 2) are present as common markers of the PVAc binder in both cases, but sample (a) contains dibutyl phthalate (peak 6) as external plasticizer. Peak 5 was recognized as bis(2-methylpropyl)-phthalate which is formed from dibutylphthalate isomerization, while butyl acetate (peak 3) and butyl benzoate (peak 4) are secondary products of recombination reactions occurring during the pyrolysis. Sample (b), however,... 

The line width of the X-ray source is on the order of 1 eV for A1 or Mg Ka sources but can be reduced to better than about 0.3 eV with the use of a monochromator. A monochromator contains a quartz crystal which is positioned at the correct Bragg angle for A1 Ka radiation. The monochromator narrows this line significantly and focuses it onto the sample. It also cuts out all unwanted X-ray satellites and background radiation. An important advantage of using a monochromator is that heat and secondary electrons generated by the X-ray source cannot reach the sample. 

Spectral interferences are due to substances in the flame that absorb the same wavelength as the analyte, causing the absorbance measurement to be high. The interfering substance is rarely an element, however, because it is rare for another element to have a spectral line at exactly the same wavelength, or near the same wavelength, as the primary line of the analyte. However, if such an interference is suspected, the analyst can tune the monochromator to a secondary line of the analyte to solve the problem. 

Despite the measurement of the emitted radiation by these means it is still possible for scattered or reflected incident radiation to reach the detector. To prevent this, fluorimeters require a second monochromating system between the sample and the detector. Many simple fluorimeters use filters as both primary and secondary monochromators but those instruments that use true optical monochromators for both components are known as spectrofluo-rimeters. Other instruments incorporate a simple cut-off filter system for the emitted radiation while retaining the optical monochromator for the excitation radiation. Because the wavelengths of both excitation and emission are characteristic of the molecule, it is debatable which monochromator is the most important in the design of a fluorimeter. 

P-XRD data were recorded on a Bruker AXS D8 advance diffractometer (Cu-Ka) in 0/0 geometry with a secondary monochromator. 

Phase identification was performed by X-ray diffraction in Bragg-Brentano geometry with Cu-Ka radiation and a secondary monochromator. A rotating sample holder was used in order to minimize texture effects in the x-y plane and to offset the effects of the rather large grain size. Diffractograms were taken as a function of depth after stepwise removal of layers with an abrasive diamond disk. 

For the studies presented in Sections IV and V, measurements were taken at IBM Beamline U8B (12) at the National Synchrotron Light Source. Monochromator energy resolution at the carbon K-edge was 0.2 eV. A display analyzer (13) with channel plates was used to detect secondary electrons in an 8 eV window centered at 42 eV. This energy was selected so that only the most surface-sensitive (minimum escape depth) electrons were detected. 

CA 46, 4798 (1952)(Line-reversal technique in detn of temp of gun flash is discussed. Monochromator is used to isolate Na, K, water-vapor radiation at 0.589, 0.77 0.942 microns resp. Peak temp values detd for external gaseous explns commonly known as secondary flash associated with firing a gun)... 

A fluorescence spectrometer (or spectrofluorimeter) is provided with two monochromators to study both the excitation and fluorescent spectra. The two spectra are used in the elucidation of structure and identification of the molecule, as well as in defining the optimum conditions for quantitative determination. A fluorimeter uses filters in each beam. For the observation of luminescence decay, shutters are interposed alternately in the primary and secondary beams. 

Powder X-ray diffraction (XRD) was performed with a Kristalloflex Siemens D5000 diflfiactometer using the K radiation of Cu ( =1.5418 A) and equipped with a secondary curved graphite monochromator. The analyses were done in the continuous coupled /2 reflection mode. Two- angles were scanned between 5° and 70° at a rate of 0.45° min. ... 

XRD (X-Ray powder Diffraction) analysis was performed with a Philips X PERT diffractometer equipped with a secondary monochromator data were collected in the 15<20<9O° angular region, with 0.03° 20 step and 20 s/step accumulation time the CuKa radiation (X=l.54178 A) was used. 

Figure 17.9 XPS and UPS measurements of neat and different mixed films of Cgo and CuPc (a) Cls spectra (excitation monochromated A1 K ), (b) HOMO levels (excitation He II) and (c) secondary electron...

For photoelectron spectroscopy organic layers (neat films and mixtures) with a nominal thickness of 25 nm were deposited on 100 nm thick gold films which were thermally evaporated onto oxidised Si wafers. The electronic properties of the films were characterised using X-ray and ultraviolet photoelectron spectroscopy (XPS, UPS) by employing monochromated A1 Ka radiation (hv = 1486.7 eV) for measurement of the core levels as well as ultraviolet radiation [He I (hv = 21.2 eV) and He II (hv = 40.8 eV)] for an analysis of the occupied states near the Fermi level. For a measurement of the secondary electron cut-off to determine the sample work function exactly, an additional bias (-2 V and -5 V) was applied to the sample. 

Rubrene was purchased from Aldrich (elemental purity > 98%) and additionally purified by gradient sublimation Freshly cleaved mica (001) was used as substrate. Rubrene thin films were deposited by hot wall epitaxy in a vacuum chamber with a base pressure below 10 Pa at different deposition rates and substrate temperatures (Ts). Pole figures were measured with a Philips X pert x-ray diffractometer using CrKa radiation and a secondary side graphite monochromator. Specular scans were performed on a Bruker D8-Discover diffractometer using CuKa radiation. POWDER CELL and STEREOPOLE were used for the evaluation of the specular scans and simulation of pole figures. 

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