  A numerically cheap way to obtain structural information about clusters of
rare gas atoms at low temperatures is developed. The semiclassical frozen
Gaussian imaginary time propagator is extended such that it can account for the
mean values of all inter-atomic distances in the cluster and their variances.
To reduce the required numerical effort an approximation for the mean values is
developed which preserves the quality of the results offered by the
semiclassical ansatz. The method is applied to the $\text{Ar}_6$ cluster. It is
found that the cluster dissociates almost in one step to six free atoms when
the temperature is increased. Precursors of the dissociation are only
observable in the distances of the atoms via the appearance of a second isomer.
The process is almost classical. However, the method is able to resolve small
differences in the temperatures at which the dissociation takes place and in
the mean distances of the bound configuration.
