Diffusion-influenced reactions involving a reactant with two active sites.

Area of Science:

• Chemical kinetics
• Physical chemistry
• Computational chemistry

Background:

• Diffusion-influenced reactions are crucial in chemical processes.
• Modeling reactants as spheres with multiple reactive sites presents challenges in predicting reaction rates.
• Understanding the interplay between diffusion and reaction kinetics is essential for molecular interactions.

Purpose of the Study:

• To develop an approximate analytic expression for the rate coefficient of diffusion-influenced reactions involving a sphere with two reactive patches.
• To evaluate the accuracy of the derived expression using computer simulations and exact analytic solutions.
• To present an efficient Brownian dynamics method for calculating time-dependent rate coefficients for reactants with multiple active sites.

Main Methods:

• Utilized the Wilemski-Fixman-Weiss decoupling approximation.
• Employed a multivariable Padé approximation for deriving the analytic rate coefficient.
• Validated the theoretical model against computer simulations and exact analytic expressions for a specific case.
• Developed an efficient Brownian dynamics method for time-dependent calculations.

Main Results:

• An accurate approximate analytic expression for the rate coefficient was derived.
• The method effectively estimates the magnitude of diffusive interference effects between two reactive patches on a sphere.
• The Brownian dynamics method provides an efficient approach for time-dependent rate coefficient calculations.
• The developed theory shows good agreement with simulation data and exact solutions.

Conclusions:

• The proposed analytic theory accurately predicts reaction rates influenced by diffusion for systems with two reactive sites.
• The Wilemski-Fixman-Weiss and Padé approximations offer a robust framework for such calculations.
• The efficient Brownian dynamics method extends applicability to complex systems with multiple active sites.
• This work enhances the understanding of molecular interactions and reaction dynamics in solution.