Finite-Temperature Dimer Method for Finding Saddle Points on Free Energy Surfaces.

Area of Science:

• Computational Chemistry
• Chemical Physics
• Materials Science

Background:

• The dimer method is effective for locating saddle points on potential energy surfaces.
• Finite-temperature effects necessitate describing dynamics in low-dimensional reaction coordinates, with transition states as saddle points on the free energy surface.
• Traditional dimer methods are unsuitable for free energy surfaces as they are not known a priori.

Purpose of the Study:

• To develop a finite-temperature dimer method for accurately and efficiently searching saddle points on free energy surfaces.
• To address the limitations of traditional dimer methods in finite-temperature, high-dimensional systems.

Main Methods:

• A constrained rotation dynamics of the dimer system is employed to sample various dimer orientations.
• An efficient averaging technique is utilized to approximate the most unstable direction.
• The approximated unstable direction guides the dimer evolution towards saddle points by reversing the force component.

Main Results:

• The developed finite-temperature dimer method demonstrates efficiency in locating saddle points on free energy surfaces.
• Numerical results validate the method's capability in complex system dynamics.

Conclusions:

• The novel finite-temperature dimer method provides an effective approach for identifying transition states on free energy surfaces.
• This advancement is significant for molecular dynamics simulations where finite-temperature effects are critical.