We demonstrate that Widom's particle insertion technique provides a
convenient and efficient method to determine the effective pair interaction
between complex, composite soft-matter particles in the zero-density limit. By
means of three different test systems, i.e. amphiphilic dendrimers,
electrostatic polymers and colloids coated with electrostatic polymers, we
demonstrate the validity and the power of the presented method.Comment: 7 pages, 4 figures, to be published in Soft Matte