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, p0, 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 = α2D0 where D0 is the pre-exponential factor of effective diffusivity and α is a geometrical parameter of specimen.

► Derivation of the Kissinger formula in the case of diffusion-controlled desorption. ► Good fitting to spectra generated by the McNabb–Foster model. ► Applicability in both detrapping- and diffusion-controlled desorption. ► A simple and effective technique to deduce hydrogen trapping parameters.