Chemical activation through super energy transfer collisions.

Area of Science:

• Chemical Physics
• Physical Chemistry
• Reaction Dynamics

Background:

• Molecular energy transfer (ET) typically follows an exponential probability decrease with energy transferred.
• The concept of

Purpose of the Study:

• Investigate the efficiency of energy transfer in atom-molecule collisions.
• Determine if molecules can be activated by large energy amounts in single collisions.
• Assess the impact of such collisions on molecular reactivity and equilibrium.

Main Methods:

• Time-resolved infrared emission spectroscopy.
• Quasi-classical trajectory calculations.
• Ab initio potential energy surface modeling.

Main Results:

• Collisions between translationally hot H atoms and molecules like acetylene (HCCH) show efficient "super energy transfer".
• Chemical complex formation facilitates the transfer of chemically significant energy amounts.
• ~10% of H + HCCH collisions (at ~60 kcal/mol) transfer up to 70% of energy to internal molecular modes.

Conclusions:

• Atom-molecule collisions can achieve surprisingly high energy transfer efficiencies.
• This efficient ET mechanism significantly influences chemical reactivity and equilibrium in relevant systems.
• Findings challenge conventional models of molecular energy transfer.