  We present a genetic algorithm developed (GA) to optimize molecular AF_6
cluster configurations with respect to their energy. The method is based on the
Darvin's evolutionary theory: structures with lowest energies survive in a
system of fixed number of clusters. Two existing structures from a given
population are combined in a special way to produce a new structure (child)
which is kept if its energy is lower than the highest energy in the ensemble.
To keep the population constant we reject the structure with the highest
energy. This algorithm gives a better result than the optimization techniques
used previously. Using the GA we have found a new structure corresponding to
the (seemingly) global minimum. The most important result is that the new
structure is detected only if the molecular cluster contains more than a
critical number of molecules.
