Izvorni znanstveni članak
Analysis of thermal desorption spectra. Application to Pd/O2 system
Petar Pervan
; Institute of Physics of the University, 410001 Zagreb, Yugoslavia
Milorad Milun
; Institute of Physics of the University, 410001 Zagreb, Yugoslavia
Sažetak
Methods for thermal desorption spectra analysis, developed within the Polanyi¬-Wigner model of thermal desorption kinetics, are reviewed. It is shown that Redhead's method produce substantial errors in calculated energy of desorption. Arrhenius plot method and Chan, Aris and Weinberg's (CAW) method give the energy of desorption E without the preexponential factor (v) included in the calculations. These two methods are based on the assumption that E and v are constants. Using the CAW method as an example we show that these methods can be applied in some circumstances to the systems in which E depends on coverage. This approach has been tested by the analysis of simulated and experimental (O2/polycrystalline Pd) thermal desorption spectra. The experimental spectra are characteristic of the second order kinetics with coverage dependent E. This dependence may be interpreted as due to the existence of the repulsive lateral interactions in the adsorbed oxygen layer.
Ključne riječi
Hrčak ID:
329997
URI
Datum izdavanja:
7.1.1986.
Posjeta: 379 *