We have studied random sequential adsorption (RSA) of three classes of polygons with rounded corners: rectangles, isosceles triangles and orthogonal triangles. Using the algorithm that allows generating strictly saturated random packing, we have systematically determined the mean saturated packing fraction for RSA configurations built by these shapes. The main aim was to find out the figure that forms the densest random configuration. Although for rounded rectangles the packing fractions were lower than for discorectangles, the densities reached for some rounded isosceles and right triangles exceed the highest known two-dimensional packing fraction for configurations built of unoriented monodispersive objects. The microstructural properties of several packings were discussed in terms of the two-point density autocorrelation function.

Saturated random sequential adsorption packings built of two-dimensional ellipses, spherocylinders, rectangles, and dimers placed on a one-dimensional line are studied to check analytical prediction concerning packing growth kinetics [A. Baule, Phys. Rev. Let. 119, 028003 (2017)]. The results show that the kinetics is governed by the power-law with the exponent d = 1.5 and 2.0 for packings built of ellipses and rectangles, respectively, which is consistent with analytical predictions. However, for spherocylinders and dimers of moderate width-to-height ratio, a transition between these two values is observed. We argue that this transition is a finite size effect that arises for spherocylinders due to the properties of the contact function. In general, it appears that the kinetics of packing growth can depend on packing size even for very large packings.

No abstract