Move
the mouse over different DS_{f} / k ratios to see a
schematic representation of this effect

The probability of an interfacial molecule being melted off, i.e. the fraction of this
type of molecule which will be detached, is given by a Boltzmann expression . Comparison of
these probabilities gives a picture of the smoothness of the interface. For example, a
smooth interface will be one for which there are few remaining molecules with n=1
and many with n=5, i.e. for which this ratio is large

Using the expression DS_{f}
= DH_{f}
/ T_{f}, and assuming that the temperature
is close to T_{f},
this ratio can be written as .

A high value (³10)
for this ratio, obtained when DS_{f}
/ k is greater than about 5-6, will give a smooth interface.