Exploring mechanochemical reactions at the nanoscale: theory versus experiment

Area of Science:

• Physical Chemistry
• Materials Science
• Chemical Engineering

Background:

• Mechanochemical reaction pathways are typically found using force-displaced stationary points.
• Investigating these pathways is crucial for understanding and designing chemical reactions driven by mechanical force.

Purpose of the Study:

• To test the validity of using the steepest-descent pathway (SDP) from the transition state to reactants as a simpler alternative for studying mechanochemical reaction kinetics.
• To compare theoretical predictions using SDP with experimental results for a specific system.

Main Methods:

• Calculated mechanochemical reaction rates by compressing initial and transition-state structures.
• Measured reaction rates experimentally using an atomic-force-microscopy (AFM) nanomechanochemical reactor under compression.
• Determined reaction rate as a function of contact stress.

Main Results:

• The steepest-descent pathway (SDP) method provided accurate mechanochemical reaction kinetics.
• Experimental results for methyl thiolate decomposition on Cu(100) agreed well with theoretical predictions.
• The study confirmed the postulate that SDP is a reliable method for mechanochemical kinetics.

Conclusions:

• The steepest-descent pathway (SDP) is a viable and simpler approach for calculating mechanochemical reaction rates.
• This method facilitates the study of more complex mechanochemical reactions and aids in designing new syntheses.
• The findings provide insights into factors controlling mechanochemical reactivity.