Second ion mass spectroscopy

Chemical bond information for materials can be determined with inferred and/or Raman spectroscopy, SIMS (second ion mass spectroscopy) and TOF-SIMS (time-of-flight secondary ion mass spectroscopy). Chemical bond information, especially on the materials surfaces, can be obtained with TOF-SIMS. Micro-IR and micro-Raman spectroscopes have been developed to map the chemical compositions of samples on a micrometer scale. The chemical species presented in MEAs after different lifetime tests were studied by a Raman spectrometer [36]. Cheng and co-workers observed a significant shift in the Raman bands of ruthenium oxide (RUO2) from 528, 646, and 716 cm in a single crystal to 506, 616, and 675-680 cm of amorphous ruthenium oxide at the anode side of MEAs. Although the RUO2 was initially present in the powder sample of the anode... 

During a considerable long period, the gaseous chemisorption method is the sole one to probe the surface species of solid catalysts. Some of the modern techniques for surface measuring are Measurements of effusion works, Auger electron spectroscopy (AES), Electron spectroscopy of chemical analysis (ESC A), X-ray photoelectron spectroscopy (XPS), Electron probe microanalysis (EPMA), Ion probe microanalysis (IPM), Ion scattering spectroscopy (ISS), Second ion mass spectroscopy (SIMS), Low energy electron diffraction (LEED), Vibration spectrum and Mossbauer spectroscopy etc. All these techniques provide favorable conditions for the surface research indepth. 

Electrochemical impedance spectroscopy (EIS) and second ion mass spectroscopy (SIMS) were used to investigate the mechanisms of oxygen reduction on LSM surfaces. EIS with microelectrodes was employed at the Max Plant Institute to investigate the rate-limiting process with LSM on YSZ. They found the corresponding electrode resistance was approximately proportional to the inverse... 

One type of method is an energy analysis of electrons emitted from the surface with Auger-electron-spectroscopy (AES), X-ray photoelectron spectroscopy (XPS), and ultraviolet photoelectron spectroscopy (UPS). A second way is to sputter the surface and analyze the emitted particles by mass spectroscopy. This method is called secondary ion mass spectroscopy (SIMS). A third method is based on the scattering of He ions from the surface and the analysis of the scattering parameters (Rutherford backscattering). 

The diffusion of Mg was studied in GaN layers grown onto sapphire substrates by atmospheric-pressure metalorganic vapor-phase-epitaxy in a so-called home-made reactor. Secondary ion mass spectroscopy was used to visualize the Mg profiles in 2 types of multi sub-layer GaN structures. One structure was grown with a variable flow of Ga precursor, and the other with a variable growth temperature. In both cases, the Mg dopant precursor (Cp2Mg) flow was constant. Using Pick s second law to fit... 

Surface-extended X-ray absorption fine structure (analysis) spectroscopy Sum frequency generation Second harmonic generation Surface ionization Secondary ion mass spectroscopy Subtractively normalized interfacial Fourier transform infrared spectroscopy Single potential alteration infrared (spectroscopy)... 

Chemists use an instrument called a mass spectrometer to measure the relative abundance of isotopes. There are different kinds of mass spectrometers, but the basic idea is to measure the mass of a substance by applying a force. The response to this force depends on the object s mass—think of Newton s second law, where acceleration equals force divided by mass. In the case of mass spectroscopy, the substances to be measured are first ionized—they are made into charged particles called ions by stripping electrons. A magnetic field deflects the motion of an ion, and the deflection depends on the ion s mass, most of which is due to the protons and neutrons in the nucleus. The technique separates different isotopes and measures their abundance in a given sample. 

Figure 12-1. Schematic diagram to illustrate double resonance techniques, (a) REMPI 2 photon ionization. The REMPI wavelength is scanned, while a specific ion mass is monitored to obtain a mass dependent SI <- SO excitation spectrum, (b) UV-UV double resonance. One UV laser is scanned and serves as a burn laser, while a second REMPI pulse is fired with a delay of about 100 ns and serves as a probe . The probe wavelength is fixed at the resonance of specific isomer. When the burn laser is tuned to a resonance of the same isomer it depletes the ground state which is recorded as a decrease (or ion dip) in the ion signal from the probe laser, (c) IR-UV double resonance spectroscopy, in which the burn laser is an IR laser. The ion-dip spectrum reflects the ground state IR transitions of the specific isomer that is probed by the REMPI laser, (d) Double resonance spectroscopy can also use laser induced fluorescence as the probe, however that arrangement lacks the mass selection afforded by the REMPI probe...

Drug A formulation lots were then examined for evidence of iron as well as other transition metal ions. Inductively coupled plasma-mass spectroscopy (ICP-MS) was used initially in a semiquantitative scanning mode. This mode of detection allows for determination of the elements sodium through mercury with detection limits of about Ippb with absolute errors typically about 30%. The three manufactured batches shown in Table 3 were examined. With the exception of iron, no first-, second-or third-row transition metal ion was found in any lot at greater than 2 ppb. Most transition metals were undetectable. Iron, in contrast, was detected at between 10 and 30 ppb. Iron levels were quantitated more accurately by using the method of standard... 

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