  We have simulated encounters between planetary systems and single stars in
various clustered environments. This allows us to estimate the fraction of
systems liberated, the velocity distribution of the liberated planets, and the
separation and eccentricity distributions of the surviving bound systems. Our
results indicate that, for an initial distribution of orbits that is flat in
log space and extends out to 50AU, 50% of the available planets can be
liberated in a globular cluster, 25% in an open cluster, and less than 10% in a
young cluster. These fractions are reduced to 25%, 12% and 2% if the initial
population extends only to 20AU. Furthermore, these free-floating planets can
be retained for longer than a crossing time only in a massive globular cluster.
It is therefore difficult to see how planets, which by definition form in a
disc around a young star, could be subsequently liberated to form a significant
population of free floating substellar objects in a cluster.
