OPTimized exchange density

Xu X, Goddard III WA (2004a) Assessment of Handy-Cohen optimized exchange density functional (OPTX), J Phys Chem A, 108 8495-8506... 

Grabo T, Gross EKU (1995) Density-functional-theory using an optimized exchange-correlation potential, Chem Phys Lett, 240 141-150... 

It has been shown that the current exchange density increases up to 70°C, but there is no data for this above 100°C, again there is a critical need to measure this under real fuel cell conditions. Much work is being undertaken in precious metal alloy catalysts where Pt is combined with one or more other metals and in nonprecious metal catalysts [77]. These new catalytic materials are being studied in aqueous acid or in ME As at 100% RH, very little data exists on how these materials will behave under hot and dry conditions. In fact the development of new catalyst for fuel cells run under hot and dry conditions may require there optimization outside of aqueous or water-saturated systems. 

For (AGh 0), these two regimes are approximately balanced, and a maximum in the exchange current density is predicted. This is the optimal value of the descriptor, and it immediately suggests that a reasonable goal for a computational, combinatorial electrocatalyst search is to find alloys with AGh values close to zero. 

Becke, A. D., 1997, Density-Functional Thermochemistry. V. Systematic Optimization of Exchange-Correlation Functionals , J. Chem. Phys., 107, 8554. 

Density functional theory has also been applied successfully to describe the solvent exchange mechanism for aquated Pd(II), Pt(II), and Zn(II) cations (1849 ). Our own work on aquated Zn(II) (19) was stimulated by our interest in the catalytic activity of such metal ions and by the absence of any solvent (water) exchange data for this cation. The optimized transition state structure clearly demonstrated the dissociative nature of the process in no way could a seventh water molecule be forced to enter the coordination sphere without the simultaneous dissociation of one of the six coordinated water molecules. More... 

The primary optimization target of CLs is the effectiveness factor of Pt utilization, Tcl- It includes a factor, that accounts for statistical limitations of catalyst utilization that arise on a hierarchy of scales, as specified in the following equafion. defermines the exchange current density ... 

---