Grand challenges chemical systems

The presence of an (applied) potential at the aqueous/metal interface can, in addition, result in significant differences in the reaction thermodynamics, mechanisms, and structural topologies compared with those found in the absence of a potential. Modeling the potential has been a challenge, since most of today s ab initio methods treat chemical systems in a canonical form whereby the number of electrons are held constant, rather than in the grand canonical form whereby the potential is held constant. Recent advances have been made by mimicking the electrochemical model... 

Modeling electrochemical systems from first principles presents a considerable challenge. Quantum mechanical simulations are typically carried out within the canonical ensemble formalism where the number of electrons remains constant. The free energy is calculated with a constant temperature, volume and number of electrons F(T, F, Ne). Electrochemical systems, on the other-hand, are typically performed at a constant chemical potential in the grand canonical ensemble where p(T, F, Ne) is a constant. Throughout this book we have presented examples where the number of electrons is preserved upon chemical reaction. In order to model an electrochemical system, we would have to model... 

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