  The surface energy is one of the fundamental properties nuclei, appearing in
the simplest form of the semi-empirical mass formula. The surface enery has an
influence on e.g. the shape of a nucleus and its ability to deform. This in
turn could be expected to have an effect in fusion reactions around the Coulomb
barrier where dynamical effects such as the formation of a neck is part of the
fusion process. Frozen Hartree-Fock and Time-Dependent Hartree-Fock
calculations are made for a series of effective interactions in which the
surface energy is systematically varied, using $^{40}$Ca + $^{48}$Ca as a test
case. The dynamical lowering of the barrier is greatest for the largest surface
energy, contrary to naive expectations, and we speculate that this may be due
to the variation in other nuclear matter properties for these effective
interactions
