Fig. 4

Parallelized unimolecular and bimolecular reactions. a Time profiles of A in the dissociation reaction \(\mathrm {A} \overset {k}{\rightarrow } \mathrm {B} + \mathrm {C}\). b The corresponding time profiles of B and C. c Effects of volume occupancy on the rate of the dissociation reaction on HCP lattice. ϕ denotes the fraction of voxels occupied by crowder molecules. In the original method, the reaction fails if there are no vacant voxels among the 12 nearest neighbors of the reactant molecule to place the second product molecule. In the vacated voxels approach, a diffusing molecule from a nearest neighbor is selected randomly and moved to one of its nearest neighbors to allocate a vacant voxel for the product. Simulation model parameters: total volume was 90 μm³ with 64³ lattice, initial number of A molecules was 50,000, crowder molecules were added to achieve ϕ as shown, the diffusion coefficient of A, B, C and crowder molecules was 10 μm³s⁻¹, and 100 runs for each ϕ. d Time profiles of reactants and products in the reversible reaction \(\mathrm {B} + \mathrm {C} \overset {k_{f}}{\underset {k_{r}}{\rightleftarrows }} \mathrm {A}\)