Aspects of electronically stimulated processes of chemisorbed molecules

We discuss recent insights into the dynamical nature of electron- and photon-stimulated surface processes for chemisorbed molecules. Much of what we have learned stems from the correlation of quantum-resolved data on the products with the nature of the excited state(s), the excitation lifetimes, and the multidimensional potential energy surfaces. The latter are particularly important when two or more degrees of freedom in the adsorbates determine the dynamics and yields. Rapid advances in local-density functional approximation calculations now allow us to characterize the multidimensional aspects of ground slate potential energy surfaces for chemisorbed molecules.