Several types of instrumentation are available to study the thermodynamics and kinetics of gas adsorption and desorption processes. A highly calibrated Thermal Desorption Spectrometer has been built and it yields quantitative information about gas dissociation and decomposition pathways on surfaces. Molecular beam dosers provide a means for accurate gas exposure directly at the sample surface. A gas chromatograph / mass spectrometer is particularly useful for analyzing the products of catalytic reactions and exhausts from gas sensor arrays.