  The distance-resolved effective interaction between two star polymers in a
good solvent is calculated by Molecular Dynamics computer simulations. The
results are compared with a pair potential proposed recently by Likos et al.
[Phys. Rev. Lett. 1998, 80, 4450] which is exponentially decaying for large
distances and crosses over, at the corona diameter of the star, to an ultrasoft
logarithmic repulsion for small distances. Excellent agreement is found in a
broad range of star arm numbers.
