Molecular Simulation of Chemical Reaction Equilibrium by Computationally Efficient Free Energy Minimization

Area of Science:

• Computational Chemistry
• Chemical Engineering
• Molecular Simulation

Background:

• Simulating chemical reaction equilibrium (CRE) is crucial but computationally challenging.
• The traditional reaction ensemble Monte Carlo (REMC) method is inefficient and difficult to parallelize.
• Existing methods often require system-specific adjustments and complex sampling techniques.

Purpose of the Study:

• To introduce a novel, computationally efficient algorithm for CRE simulation.
• To leverage modern parallel computing capabilities for molecular simulations.
• To provide a generally applicable method for systems of varying complexity.

Main Methods:

• Developed a reaction ensemble molecular dynamics (ReMD) algorithm.
• Utilized parallel computing features available in molecular dynamics software (GROMACS).
• Employed a free energy minimization approach with iterative approximation using an ideal solution model.
• Introduced an *a posteriori* method for estimating low-concentration species.

Main Results:

• The ReMD algorithm demonstrates straightforward implementation and scalability.
• It effectively simulates CRE, overcoming the computational bottlenecks of REMC.
• Successfully applied to the N2-O2-NO and ammonia synthesis systems.

Conclusions:

• ReMD offers a significant advancement in simulating CRE.
• Its parallelizability and general applicability make it a valuable tool for chemistry and chemical engineering.
• The method provides an efficient alternative for complex molecular simulations.