Introduction to Surface Chemistry and Catalysis (John Wiley&Sons, Inc., New York)
- G. A. Somorjai
The ultimate goal in chemistry is to understand on a fundamental level how bonds are broken and reformed during chemical reactions. In many cases we can draw simple pictures of how electrons flow with respect to electron pair redistributions or electrostatic interactions along a reaction path. For many systems bonding can often be understood in terms of molecular orbitals and reactivity in dynamical rearrangements of different molecular states. Such knowledge provides the basis for the understanding of chemical trends and predicting chemical reactivity for many chemical compounds. Since the excitation and probe steps with conventional optical lasers involve valence electrons that are delocalized over many atomic centers it is difficult to study complex systems. It would be an important development if we can probe how molecular orbitals are transformed during a chemical reaction in an atom-specific way around the center where the interesting chemistry takes place. This can be achieved using core level excitations and decay spectroscopy . Nearly all chemical systems of importance contain C, N and O atoms. In order to access the C1s, N1s and O1s levels for ultrafast spectroscopy we need to use soft x-rays in the energy region between 280-550 eV. This would open new prospects to study time-resolved changes in the electronic structure of complex systems, such as surface reactions, catalysis, hydrogen-bonded systems, aqueous solutions, polymers and biological molecules.