Reaction rate from added vibrational energy

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SUMMARY

The discussion centers on the impact of added vibrational energy on the reaction rate between molecules. The Arrhenius equation is referenced as a foundational concept, but it does not account for the specifics of vibrational, rotational, and kinetic energies. The conversation suggests that exciting a vibrational mode may lower activation energy and increase the effective relative velocity during molecular collisions. The participants propose exploring equations that adapt the Arrhenius framework to include these detailed energy considerations.

PREREQUISITES
  • Understanding of the Arrhenius equation and its limitations
  • Knowledge of molecular kinetic, vibrational, and rotational energy concepts
  • Familiarity with activation energy and its role in chemical reactions
  • Basic principles of molecular collisions and steric effects
NEXT STEPS
  • Research adaptations of the Arrhenius equation for vibrational energy effects
  • Study the equipartition theorem in the context of molecular energy distribution
  • Explore the concept of activation energy in detail, focusing on vibrational modes
  • Investigate the role of steric parameters in reaction kinetics and collision theory
USEFUL FOR

Chemists, molecular physicists, and anyone interested in the detailed mechanics of reaction kinetics and energy transfer in molecular interactions.

sparkle_pony
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I have a molecule with a certain kinetic, vibrational, and rotational energy.

It absorbs a photon which excites a vibrational mode.

I want to find an equation that describes how the molecules reaction rate with another molecule might change given the added vibrational energy.

Is there a name for this type of equation? If I wanted to pick up a textbook to learn it what would the subject of that textbook be?
 
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The only thing I can think of is the old, good Arrhenius equation - but it doesn't care about details, it just calls for the temperature (which reflects averaged energy of molecules, without differentiating between kinetic, rotational and vibrational).

Somehow I doubt you will find kind of equation you described.
 
Arrhenius equation may be adaptable...

Temperature: Temp is the average kinetic energy of all energy modes (translational, vibrational, and rotational). I probably could find an equation for calculating the new temperature, after photon absorption, assuming that the energy was equipartitioned beforehand.

Activation Energy: Exciting a vibrational mode might make that bond easier to break. This may lower the activation energy.

Steric parameter: If a collision with another reaction precursor occurs along the axis of vibration (i.e. one of the molecular atoms "swings" or "pushes" into the other precursor, thus raising the "effective relative velocity" at the moment of collision) then I can imagine a greater pre-exponential term.

Any thoughts on what terms would change, or equations to describe their change?

Assume the collision (reaction) occurs before relaxation of the excited vibrational state by another means.
 

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