  An explicit expression is given for the correlation function of blinking
systems, i.e. systems exhibiting light and dark periods in their fluorescence.
We show through the example of terrylene in a crystalline host that it is
possible to determine by means of this explicit expression photo-physical
parameters, like Einstein coefficients and the mean light and dark periods by a
simple fit. In addition we obtain further parameters like the frequency of the
various intensity periods and the probability density of photons scattered off
the host crystal. It turns out that this approach is simpler and allows greater
accuracy than previous procedures.
