done using a so-called simplified method; the "Redhead" method, assuming the exponential prefactor and the desorption energy to be independent of the surface coverage. After 1990 and with use of computer algorithms TDS spectra were analyzed using the "complete analysis method" or the "leading edge method". These methods assume the exponential prefactor and the desorption energy to be dependent of the surface coverage. Several available methods of analyzing TDS are described and compared in an article by A.M. de JONG and J.W. NIEMANTSVERDRIET. During parameter optimization/estimation, using the integral has been found to create a more well behaved objective function than the differential. Theoretical Introduction Thermal desorption is described based on the Arrhenius equation. where the desorption rate [mol/(cm2 s)] as a function of , order of desorption, surface coverage, pre-exponential factor [Hz] as a function of , activation energy of desorption [kJ/mol] as a function of , gas constant [J/(K mol)], temperature [K]. This equation is difficult in practice while several variables are a function of the coverage and influence each other. The “complete analysis method” calculates the pre-exponential factor and the activation energy at several coverages. This calculation can be simplified. First we assume the pre-exponential factor and the activation energy to be independent of the coverage. We also assume a linear heating rate: (equation 1) where: the heating rate in [K/s], the start temperature in [K], the time in [s]. We assume that the pump rate of the system is indefinitely large, thus no gasses will absorb during the desorption. The change in pressure during desorption is described as: (equation 2) where: the pressure in the system, the time in [s]. , the sample surface [m2], a constant, volume of the system [m3], the desorption rate [mol/(cm2 s)], , the pump rate, volume of the system [m3], We assume that is indefinitely large so molecules do not re-adsorp during desorption process and we assume that is indefinitely small compared to and thus: (equation 3) Equation 2 and 3 lead to conclude that the desorption rate is a function of the change in pressure. One can use data in an experiment, which are a function of the pressure like the intensity of a mass spectrometer, to determine the desorption rate. Since we assumed the pre-exponential factor and the activation energy to be independent of the coverage. Thermal desorption is described with a simplified Arrhenius equation: (equation 4) where: