In a real example of such kinetic problems, let's investigate the binding kinetics of a fluorescent dye molecule, oxazole yellow dimer (YOYO-1), to stretched and immobilized phage λDNA molecules (Fig. ). This is a common DNA staining and imaging protocol . YOYO-1 is positively charged, the glass substrate is positively charged, and the DNA is negatively charged. We can assume the binding has no energy barrier, i.e. any dye entering the catching volume defined by the physical size of the molecules and the Debye length of the buffer solution gets caught. Debye length describes the distribution of the electric fields near the molecules. YOYO-1 is nonfluorescent in the solution and when bound and intercalated into the DNA base pairs (with an energy barrier) it is fluorescent. We have a pretty accurate theory to predict the diffusion coefficient of YOYO-1 in the solution, namely, the Stokes-Einstein-