Effect of probe-to-probe collisions in three-dimensional space on the measured diffusion coefficient

Authors

  • Jocam Joshua H. Camara ⋅ PH National Institute of Physics, University of the Philippines Diliman
  • Adrielle Theresa DL. Cusi ⋅ IT The Abdus Salam International Centre for Theoretical Physics
  • Caesar A. Saloma ⋅ PH National Institute of Physics, University of the Philippines Diliman

Abstract

We investigate the effects of elastic probe-to-probe collisions at diluted to dense probe crowding conditions on the diffusion coefficient D of numerically-modelled 3D Brownian motion (BM) ensembles. Homogeneous ensembles of pure isolated BM (iso) and collision-laden BM (coll) probes with a specified volume fraction ϕ (measure of crowding) are generated using an algorithm consisting of a time-driven BM subroutine and an event-driven elastic collisions subroutine. We found that despite probe-to-probe collisions, the displacement distribution of the collision-laden probes reveal approximately Gaussian distributions (implying pure BM despite collisions). Diffusion coefficients Dcoll of collision-laden probes and Diso of the isolated probes were measured using the variance of the displacement distributions. Increasing ϕ leads to a nonlinear increase in the recorded collisions in an ensemble and a higher collision probability per time step. Probe-to-probe collisions significantly affect the diffusion behavior of the system. Results show that collision-laden probes exhibit slower diffusion than isolated probes (Dcoll < Diso) where increasing crowding ϕ leads to larger deviations between Dcoll and Diso and introduce anomalous diffusion. Our work provides valuable insights into the behavior of BM probes under crowded environments.

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Issue

Article ID

SPP-2023-PB-16

Section

Poster Session B (Complex Systems, Simulations, and Theoretical Physics)

Published

2023-07-11

How to Cite

[1]
JJH Camara, ATD Cusi, and CA Saloma, Effect of probe-to-probe collisions in three-dimensional space on the measured diffusion coefficient, Proceedings of the Samahang Pisika ng Pilipinas 41, SPP-2023-PB-16 (2023). URL: https://proceedings.spp-online.org/article/view/SPP-2023-PB-16.