Corresponding states principle four parameter

The question raised above was is the principle of corresponding states applied to induced dipole surfaces (perhaps approximately) valid If the dipoles were well represented by an exponential function, like Eq. 4.1, the principle would of course be valid. However, it is quite clear that the dispersion part cannot be neglected in the induced dipole models. Moreover, for the best dipole models presently available, we need nonvanishing values b, Eq. 4.30, see p. 162. In other words, the induced dipole surfaces of rare gas pairs seem to require four-parameter functions, like Eq. 4.30, and it is not at all clear how these four parameters may be reduced to but two. The principle, therefore, seems at present to be of little practical value (if it were valid at all). 

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