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Thermal Desorption Spectroscopy Pdf Free
Thermal Desorption Spectroscopy Pdf Free

Thermal Desorption Spectroscopy Pdf Free > http://shurll.com/bjqou

Several masses may be simultaneously measured by the mass spectrometer, and the intensity of each mass as a function of temperature is obtained as a TDS spectrum. Contents 1 Desorption 2 Measurement 3 Quantitative Interpretation of TDS data 4 Theoretical Introduction 5 See also 6 References 7 External links . Thermal desorption is described with a simplified Arrhenius equation: (equation 4). This calculation can be simplified. P {displaystyle P} the pressure in the system t {displaystyle t} the time in [s] . After 1990 and with use of computer algorithms TDS spectra were analyzed using the "complete analysis method" [2] or the "leading edge method".[3] These methods assume the exponential prefactor and the desorption energy to be dependent of the surface coverage. where:. E a c t / R T m 2 = v 1 / β ∗ e − E a c t / R T m {displaystyle E{mathrm {act} }/{RT{m}}^{2}=v{1}/beta *e^{ -E{mathrm {act} }/RT{m}}} . A.

Ehasi, K. M. The desorbing NO was measured using a mass spectrometer monitoring the atomic mass of 30. where: σ 0 {displaystyle sigma {0}} is the surface area of a TDS or TPD peak. If the surface is heated, at one point, the energy transferred to the adsorbed species will cause it to desorb. Several available methods of analyzing TDS are described and compared in an article by A.M. where:. Temperature programmed desorption the Surface Science Laboratory Thermal desorption of large adsorbates . TDS spectrum 1 and 2 are typical examples of a TDS measurement. Thermal desorption is described based on the Arrhenius equation.

where:. Many researchers prefer the name TPD because it is not a spectroscopic method. where:. de JONG and J.W. See also.

"Thermal desorption of gases" Vacuum 12 (1962) p.203-211 ^ D.A. Christmann [6] have described a simple method to determine the activation energy of the second order. where:. Habenschaden and J. To measure TDS, one needs a mass spectrometer, such as a quadrupole mass spectrometer or a time-of-flight (TOF) mass spectrometer, under ultrahigh vacuum (UHV) conditions. TDS Spectrum 1 A Thermal Desorption Spectrum of NO absorbed on Platinum-Rhodium (100) single crystal. Moreover, TDS recognizes the different adsorption conditions of the same molecule from the differences between the desorption temperatures of molecules desorbing different sites at the surface, e.g. We assume that the pump rate of the system is indefinitely large, thus no gasses will absorb during the desorption. 6704223018