Abstract

THERMAL DESORPTION SPECTROSCOPY

B. Shivaveni*, A. Ajitha and V. Uma Maheswara Rao

ABSTRACT

When molecules or atoms come in contact with a surface, they adsorb onto it, minimizing their energy by forming a bond with the surface. The binding energy varies with the combination of the adsorbate and surface. If the surface is heated, at one point, the energy transferred to the adsorbed species will cause it to desorb. The temperature at which this happens is known as the desorption temperature. Thus TDS shows information on the binding energy. In particular, the spectral peak widths and the temperature at which the maximum rate of desorption occurs may be used to describe both first-and second-order desorption kinetics. An explicit application of this method in the analysis of several important classes of desorption reactions is presented.

Keywords: Thermal desorption spectroscopy, quadrupole mass spectrometer, ultra vaccum chamber.