In the Hamaker model, the velocity of the particle is compared to the adhesive forces. The particle is caught by the solid if the velocity of the particle, when touching the structure, is sufficiently small. The condition on the velocity is:
(84)
where is the adhesion (Hamaker constant), is the particle density, is the adhesion distance (AddiDict uses a value of 4⋅10-10m), and is the particle radius.
Adhesion (Hamaker constant) and Restitution, another parameter, are to be fitted in AddiDict. The restitution parameter determines the amount of energy not absorbed by the collision. The restitution value ranges from 0 to 1. If the restitution parameter is set to 1, no energy is lost, and the particle is reflected with the same speed it had before the collision.
For restitution values smaller than one, energy is absorbed by the collision and the particle slows down. For example, a 0.7 restitution value means that a particle loses part of its velocity in the collision and gets 30% slower.
Since the Hamaker model needs the particle diameter as an input, it is only available for finite particle size and not in the molecular limit.
In the Sieving model, the particles never stick to the solid, but a particle is caught by the solid if it does not move anymore and simply lies on the solid at two different points. The restitution parameter is used in the same way as in the Hamaker model.
