Reaction rate from added vibrational energy

In summary, the conversation discusses the desire to find an equation that describes how a molecule's reaction rate with another molecule may change after absorbing a photon and gaining vibrational energy. The concept of temperature and its relationship to kinetic, rotational, and vibrational energy is also mentioned, as well as the potential effects of exciting a vibrational mode on activation energy and steric parameters. The conversation ends with a request for thoughts on potential equations to describe these changes.
  • #1
sparkle_pony
24
0
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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  • #2
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.
 
  • #3
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.
 

What is "Reaction rate from added vibrational energy"?

"Reaction rate from added vibrational energy" refers to the study of how the rate of a chemical reaction is affected by the addition of vibrational energy. This energy can come from various sources such as heat, light, or other forms of energy. It is an important concept in understanding the kinetics of chemical reactions.

How does added vibrational energy affect the reaction rate?

The addition of vibrational energy can increase the reaction rate by providing the molecules with more energy to overcome the activation energy barrier. This leads to more frequent collisions and a higher chance of successful reactions.

Can different types of vibrational energy have different effects on the reaction rate?

Yes, different types of vibrational energy can have varying effects on the reaction rate. For example, heat energy can increase the average kinetic energy of molecules, while light energy can promote specific electronic transitions that may speed up or slow down the reaction rate.

How is the reaction rate affected by the concentration of the reactants?

The concentration of reactants can also affect the reaction rate from added vibrational energy. When there is a higher concentration of reactants, there are more molecules present, leading to more frequent collisions and a higher reaction rate. Conversely, a lower concentration of reactants may result in a slower reaction rate.

Are there any other factors that can influence the reaction rate from added vibrational energy?

Yes, there are several other factors that can influence the reaction rate, such as the nature of the reactants, temperature, pressure, and the presence of catalysts. These factors can all impact the energy of the molecules and their ability to overcome the activation energy barrier, ultimately affecting the reaction rate.

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