Applicability of the Kissinger's formula and comparison with the McNabb-Foster model in simulation of thermal desorption spectrum

The Kissinger's formula has been analyzed theoretically and numerically to be applicable in simulation of not only the detrapping-controlled thermal desorption but also the diffusion-controlled thermal desorption provided that a sufficient pre-exposure before thermal desorption is carried out in the diffusion-controlled desorption. The desorption activation energy or the binding energy can be evaluated by a single thermal desorption spectrum from a single type of trap site. In the case of detrapping-controlled desorption the constant parameter A in the Kissinger's formula approaches the pre-exponential factor of detrap parameter, p(0), in the McNabb-Foster model as specimen size becomes smaller. In the case of diffusion-controlled desorption where local equilibrium may be maintained and an effective diffusivity can be expressed, the A value changes according to A = alpha(2)D(0) where D(0) is the pre-exponential factor of effective diffusivity and alpha is a geometrical parameter of specimen. (C) 2011 Elsevier B.V. All rights reserved.