Light emission/absorption revisited by chemical thermodynamics

[fred_run]

Hello,

using the words of chemical thermodynamics could we say that stimulated emission of light is "catalysed" by incident photons, as well as absorption ?

In that way, does it mean that there is a kind of "activation energy" in the emission process ?

Without incident photon, spontaneous emission needs some help to jump to a lowest level (the needed energy is coming from the vaccuum). So, an incident photon should act as a "catalysor" which is able to attenuate the barrier. The stimulated emission process is "catalysed" by the external field. This can be quickly demonstrated using thermodynamics of black body and the "cinetic" relation between the Einstein's coefficients.

Could someone help me verifying this point of view (if it is a correct one) ? What possible link with quantum electrodynamics ?

Thanks

 

[fred_run]

I have got an answer to my question (from A.KASSLER lab. in Paris) : there is no activation energy for the spontaneous emission. There is an exponential decay as usual when a level is coupled to a continuum. Vacuum fluctuations are of course involved in the process but standard radiation damping plays an important role too.

 

[Entropia]

for your question!

In the context of chemical thermodynamics, we can indeed say that the stimulated emission of light is catalyzed by incident photons, just as absorption is also catalyzed by incident photons. This is because the presence of photons provides the necessary energy for the emission or absorption process to occur. In this sense, we can think of photons as a type of catalyst for light emission and absorption.

In terms of an "activation energy" in the emission process, this is not a concept that is typically used in chemical thermodynamics. However, we can think of the energy of the incident photon as the driving force for the emission process. Without this energy, the spontaneous emission process would require some external help, such as the energy from the vacuum, to occur.

The idea of using thermodynamics of black body and the kinetic relation between Einstein's coefficients to demonstrate the catalytic effect of photons in stimulated emission is a valid approach. This is because thermodynamics and kinetics are closely related in chemical systems, and the same principles can be applied to the process of light emission and absorption.

In terms of a link with quantum electrodynamics, this is a more complex topic that delves into the fundamental nature of light and its interactions with matter. While chemical thermodynamics provides a useful framework for understanding the macroscopic behavior of light emission and absorption, quantum electrodynamics offers a deeper understanding of the underlying mechanisms at the atomic and subatomic level. Both approaches are valuable in understanding light emission and absorption, and they complement each other in providing a comprehensive understanding of this phenomenon.

I hope this helps clarify your point of view and provides some insight into the relationship between chemical thermodynamics and light emission/absorption.