First Order Chemical Reactions

Based on the simulated trajectories of particles, residence times in each pore and porous material can be determined in the AddiDict post-processing. From these residence times, chemical reactions of first order can be computed as a next step.

First order chemical reactions are simple chemical reactions that describe a reduction of a reactant A (here a kind of molecules), while the catalyst is not consumed. The change in amount of [A] is determined by the rate constant :

i.e., the amount of [A] is reduced exponentially, with a half-life time of:

The remaining amount of [A] can therefore simply be computed from the residence times and the rate constant :

Short-Time Adsorption

Short-time adsorption is the effect, that particles/molecules can stick to some material for a short time interval, before continuing to move due to diffusion and/or advection.

In Track Particles & Molecules, this effect is not taken into account during the simulation of particle trajectories. However, in the post-processing, adsorption times can be defined for each solid and porous material. Each time a particle hits such a material, it is adsorbed there for the defined adsorption time. The traveled displacement of all particles is adapted according to the defined adsorption times and the number of hits with each material.