Mobility and bonding of C-60 on a Pd(110) surface were characterized by var
iable temperature scanning tunneling microscopy. Following adsorption at in
termediate temperatures (435-485 K) the motion of single molecules could be
directly monitored, and the corresponding tracer diffusion barrier was det
ermined to be (1.4 +/-0.2) eV, Upon annealing to approximate to 700 K the m
olecules undergo an irreversible bonding transition resulting in a second,
more strongly bound C-60 Species With different imaging characteristics. Th
is is attributed to a local surface reconstruction where C-60 sinks into th
e formed microscopic pits. The findings demonstrate that substrate restruct
uring may account for the coexistence of distinct C-60 species at surfaces.