Figure 5.

Plot of the applied force at the unstacking transition of poly(dA) as a function of ionic strength. Error bars represent the standard error of the mean of two to three measurements at each salt concentration. Also plotted are fitted expressions f_applied = f_tot = f_el, where f_el is the electrostatic tension as predicted by Netz (10) and Manning (11). Best-fit parameters are indicated in the legend. Parameters with an asterisk (^∗) are fixed in the fit. To see this figure in color, go online.