Path optimization by a variational reaction coordinate method. I. Development of formalism and algorithms.

Area of Science:

• Computational Chemistry
• Chemical Physics
• Reaction Dynamics

Background:

• Optimizing reaction pathways is crucial for understanding chemical reactions.
• Current methods often use discrete steps, posing challenges for continuous path representation.

Purpose of the Study:

• Introduce and demonstrate the Variational Reaction Coordinate (VRC) method.
• Provide a continuous approach to optimize reaction pathways by minimizing variational reaction energy (VRE).

Main Methods:

• Representing reaction paths using a linear expansion of continuous basis functions.
• Minimizing VRE with respect to expansion coefficients.
• Applying constraints and coupling minimization to intermediates/transition states for improved convergence.

Main Results:

• The VRC method successfully optimizes reaction paths.
• Demonstrated on the Müller-Brown surface and a 10-atom Lennard-Jones cluster with multiple transition states and intermediates.

Conclusions:

• The VRC method offers an effective continuous alternative for reaction pathway optimization.
• This approach improves convergence and handles complex reaction landscapes.