Steeply repulsive particles

The systems considered included a steeply repulsive potential, SRP, between the particles with n arbitrary ... 

For noncohesive or weakly cohesive particulate films the contact cross-sectional area, A, [42] can be related to the characteristic length of repulsion or the p-p distances at the secondary energy minimum [27, 36]. To determine ylk, a line was fitted to the most steeply rising part of the H-A isotherms (see the leftmost isotherm in Fig. 4) at the surface pressure of 2 mN/m < IT < ric-2mN/m (lie is the collapse pressure) and the intersection of the fitted line and the horizontal axis (A) gives the parameter, Tk. Dividing A by Z, the total number of particles in the boundary layer, one gets this parameter for an individual sphere, Ai. 

It follows that the short-range repulsive force F(K) between real molecules is not infinitely hard, i.e., the potential V(R) is not a vertical wall at some critical value of the center-to-center separation Ji of the colUding particles (e.g., R = d). Rather, there is a steeply increasing repulsion that is often approximated by an exponential form with a range parameter p and strength A ... 

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