Capitalistic Chemistry

The concept of “bond strength” is of essence for modeling every kind of reactive chemistry. Particularly within the field of catalysis and surface science, the interaction strength of adsorbates to surfaces affects the activity, selectivity, and stability of intermediates and transition states. Here, we introduce a simple approach to chemical reactions through an analogy with business. We regard rehybridization as the investment a molecule makes to prepare its electronic and geometrical structure to form new bonds. The resulting bond strength is the total proceeds from bond formation, and the difference (exothermicity) is the profit. The predictive power lies in the fact that any change in the electronic structure to prepare for bond formation requires the involvement of specific excited states. Thus, with knowledge of the energy needed for this excitation (investment) and the strength of the resulting interaction one can predict whether a specific reaction or bonding mode will be favored. We apply this concept to rationalize observed binding modes at surfaces and the often observed large structural changes even for “weakly” chemisorbed systems and finally to justify using small metal clusters to correct chemisorption energies from periodic DFT calculations.