INDEX future perspectives

Although only a1 and e are used as additional descriptors so far, some others might be useful in the future. One of the most apparent is the local electronic polarizability of the molecule in the vicinity of a surface segment i, which we may represent by a local refractive index n,. Such local polarizability or local refractive index would allow for a refinement of the electrostatic misfit term, which presently only takes into account an average electronic polarizability of organic molecules. It is also likely that the local electronic polarizability is of importance to the strength of hydrogen bonds, which so far in COSMO-RS are only a function of polarity. Finally, from a physical perspective, the vdW interactions should be a function of the local polarizability as well. 

The equations for money yield and real yield can be interpreted as indicating what redemption yield to employ as the discount rate in calculating the present value of an index bond s future cash flows. From this perspective, equation (12.9) shows that the money yield is the appropriate rate for discounting money, or nominal, cash flows. Equation (12.12) shows that the real yield is the appropriate rate for discounting real cash flows. 

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